382 FXPQ50 PGUM 181901 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 501 AM ChST Tue May 19 2026 .Marianas Update... The Marianas forecast remains in good shape with no updates needed, A few showers will continue to cross the area this morning, diminishing by sunrise. A high risk of rip currents for the east facing reefs through this afternoon. && .Eastern Micronesia Update... The main forecast changes were to decrease rainfall potential downward to 40 percent for today and tonight, as the better surface convergence slides west with not much activity noted upstream on satellite analysis. At majuro, we also dropped shower coverage to isolated (20 percent) probabilities for today only, as the better surface convergence and shower coverage will be delayed until this evening or later tonight for the onset. otherwise, no additional updates were needed. && .Western Micronesia Update... The main changes were to lower rainfall potential at Palau to 30 percent based on a lack of upstream activity. At Yap, we ramped POPs (Probability of Precipitation) to near 100 percent for today as convection will be prevalent this morning, becoming numerous showers and isolated thunderstorms by the afternoon. Given cloud tops surpassing -80 C, locally heavy rainfall wording was added as well. We then went with 50 percent probabilities for tonight.The Chuuk forecast remains in good shape with no updates needed. && .Prev discussion... /issued 615 PM ChST Mon May 18 2026/ Marianas Synopsis... Mostly cloudy skies and scattered showers are forecasted for the Marianas tonight. A return to isolated showers and partly cloudy skies may continue until the weekend. Combined seas are between 6 to 8 feet, and a high risk of rip currents remains along east-facing reefs at least through Tuesday afternoon. Discussion... Satellite and model trends show low-end scattered showers as the trade-wind surge and surface troughs continue to produce showers moving downstream towards the Marianas, so Probability of Precipitation (PoPs) values will remain at 30 percent for the entire region tonight. Isolated showers are expected to remain through the rest of the week, but moisture trends will continue to be monitored as the troughs south of Wake Island progress downstream over the next several days. Scatterometry shows some pockets of elevated trade winds over open waters to the far east, but models (validated by today's observations) indicate winds remaining 15 to 20 miles per hour with gusts up to 25 miles per hour for the region until the latter half of the week when the trades potentially downtrend through the weekend. A slight chance of thunderstorms is introduced in the last few periods of the forecast, but confidence is low as models struggle to agree on the source, whether it be a weak trough or a potential disturbance passing south of Guam. Regardless, this will continue to be monitored and communicated as the week progresses. Marine... Buoy and altimetry data indicated combined seas of 6 to 8 feet across the region and is expected to continue until midweek when sea heights may drop a foot or two through the rest of the week. The easterly trade winds are expected to remain moderate to fresh through the rest of the week before potentially dropping to just moderate over the weekend. Surf will remain at 9 feet tonight along east-facing reefs, so a high risk of rip currents remains at least through Tuesday afternoon. Surf conditions will continue to be monitored as the rip current risk will need to be re-evaluated tomorrow afternoon. Tropical Systems... A weak subtropical disturbance on the northwestern edge of Guam's Area of Responsibility (AOR), centered near 22N131E, has been dubbed Invest 98W by the Joint Typhoon Warning Center. 98W exists on the southwestern edge of a decaying stationary frontal boundary to the east of Taiwan, which extends east-northeast to a low-pressure system well beyond 25N137E. Numerous showers and scattered thunderstorms are seen within the moist convergent flow wrapping into 98W along its eastern flank, just south of the nearly-dissipated baroclinic zone extending from it. Invest 98W looks to remain within the region only briefly, with model guidance depicting a north to north-northwest movement along 130E, exiting north and west of the AOR by late Tuesday morning. 98W then looks to merge with an eastward-propagating mid-latitude system around midweek. Eastern Micronesia... A disorganized, unsettled pattern continues across the region. Pohnpei saw numerous showers and isolated thunderstorms throughout the morning hours, due to strong convergence along a nearby trade- wind trough. This was supported by an area of divergence aloft, associated with a broad upper-level low centered well northeast of Pohnpei, to the south of Wake Island. Himawari visible satellite this afternoon shows lingering widespread cloud cover across Pohnpei State, with patchy stratiform showers nearby. Much drier conditions prevail over Kosrae and Majuro, with most of the showers focused well to the north of Kosrae, and over the northeastern Marshall Islands. Numerous showers are also seen to the southwest of Kosrae, near and south of the Equator, associated with an Intertropical Convergence Zone (ITCZ) fragment over far southern Pohnpei State. The upper-level low to the south of Wake Island looks to shift slightly westward over the next day or so as it extends toward the west-southwest. The change in orientation of the low, in addition to the development of an upper-level high to its west near the Marianas, looks to focus strong upper-level divergence over Chuuk and Pohnpei States over the next few days. This looks to interact with a trough and convergence boundary at the surface, to support numerous showers and isolated thunderstorms for Pohnpei around Tuesday and Tuesday night. The upper-level low looks to gradually open into a trough, which will linger and weaken throughout the rest of the week. Model guidance indicates an unsettled pattern will continue through the week, with numerous to widespread showers focusing farther to the west, mainly over central Micronesia. Meanwhile, an ITCZ looks to develop near the Marshalls by the end of the week, with a series of weak troughs propagating westward along it. These features will maintain a wet pattern across the region, with at least scattered showers expected into the end of the week for all three forecast points. Benign marine conditions are expected through the week. Latest altimetry data indicates combined seas between 5 and 7 feet across much of the region. Models depict a gradual relaxation of the east to northeast trade swell throughout the week, allowing seas to diminish by a foot or two over the next several days. Western Micronesia... The main weather makers for the region are a band of convergence between Chuuk and Pohnpei, a second band of convergence near Yap Proper, and a trough over southern Palau. Over southern Palau, an east-to-west oriented trough has set up and is producing scattered showers. Model guidance suggests this trough will move through the region over the next day or so. Looking further out, a trade-wind regime is expected to return through next week. Near Yap, the convergence band is interacting with a subtle trough and is producing scattered showers that is expected to build into widespread showers with isolated thunderstorms over the evening and early morning hours. This interaction is anticipated to remain in the Yap Proper area for a day or two. Then, a series of troughs is expected to pass through the beginning of next week, anticipated tobring scattered showers to Yap. Meanwhile in Chuuk, satellite imagery shows trade-wind convergence showers to the south of Weno. Showers are expected to build into Chuuk's coastal waters overnight. Then over the week, the showers and troughs that are affecting Pohnpei now are expected to move into Weno making for a fairly wet week. Benign marine conditions are expected to continue through much of the upcoming week. Altimetry shows 2 to 4 foot seas at Palau and Yap, and 4 to 6 feet at Chuuk. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...High Rip Current Risk until 4 PM ChST this afternoon for GUZ001. MP...High Rip Current Risk until 4 PM ChST this afternoon for MPZ001>003. Marianas Waters...None. && $$ Marianas/East and West Micronesia/Tropical Update: Doll Marianas: Mesa East Micronesia: DeCou West Micronesia: Bowsher  220 FXUS61 KPHI 181900 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 300 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... Heat Advisory expanded to most of eastern Pennsylvania and northern to southern New Jersey. Small Craft Advisory issued for the New Jersey Atlantic coastal waters. && .KEY MESSAGES... 1. Hot and more humid conditions continue, with record setting early season heat probable, through Wednesday. 2. A cold front will bring some showers and thunderstorms to the region Wednesday through Thursday, then much cooler temperatures by the end of this week. && .DISCUSSION... KEY MESSAGE 1...Hot and more humid conditions continue, with record setting early season heat probable, through Wednesday. A strong upper-level ridge centered off the Southeast U.S. coast will remain in place through late Tuesday before it starts to flatten on its northwest side during Wednesday. This along with surface high pressure anchored in the western Atlantic will drive a south to southwest flow of early season (anomalous) heat across our area into Wednesday. Temperatures are forecast to peak into the 90s for many areas again Tuesday and Wednesday, except cooler along the coasts and the higher terrain. While the surface dew points will likely mix out some during peak heating due to the drier ground and boundary layer (low evapotranspiration), this stretch of early season heat, with record breaking high temperatures probable, will have potentially greater impacts. For this reason, opted to expand the Heat Advisory to the areas where the heat index criteria starts at 100F (the urban I-95 corridor criteria starts at 96F through June). While it will probably fall a little short for some areas, the potential greater impacts (lack of acclimation) is driving our decision. Where the wind turns more from the south and especially southeast will result in quite a bit of cooling due to the chilly ocean and therefore did not include the immediate coastal zones in the Heat Advisory. Peak heat indices will be 95 to nearing 100 degrees, with the core of the heat shifting a bit more south and east during Wednesday as a strong cold front starts to arrive. Based on this, portions of the Heat Advisory for areas farther north and west of I-95 only goes through Tuesday. High temperatures on Wednesday will depend on how quickly cloud cover arrives along with showers and some thunderstorms. Either way, we will have a high launching pad for temperatures to start Wednesday and it will still be rather hot. Temperatures at night will be quite warm by mid May standards. Lows will only be in the mid 60s to low 70s, which will challenge daily warmest low temperature records for May 19th. As a side note, isolated convection has developed over the central Applachians this afternoon and this activity will move to the north and northeast into this evening. Given the presence of the ridge farther east, the chance for any of this to make it to parts of our far western zones this evening is very low at the current time and therefore went with a dry forecast. KEY MESSAGE 2...A cold front will bring some showers and thunderstorms to the region Wednesday through Thursday, then much cooler temperatures by the end of this week. As mentioned above, a cold front will approach the area Wednesday and bring an end to the stretch of above normal temperatures by Thursday. Showers and thunderstorms will accompany this front as it passes through the region. Recent guidance trends continue to show the front moving through during the second half of Wednesday into Wednesday night. Given this timing, there is the threat for strong to severe thunderstorms. There remains uncertainty in the more specific details and some timing variations remain. Regarding thethreat for strong to severe thunderstorms, the cold front will be moving into an air mass that will feature plenty of instability. The better shear and forcing look to be to our north, but bulk shear values will be supportive of some storm organization along with some supportive lapse rates. All of this said, the potential is there for isolated strong to severe thunderstorms. The primary concerns with any strong to severe thunderstorm would be damaging wind gusts and large hail. General rainfall accumulation from this frontal passage looks around 0.25" or less. However, given this convection and PWAT values reaching to 1.5-2.0", localized higher amounts are certainly possible with any heavier pockets of rain. As the front sinks south into Thursday morning, it then looks to linger near or just south of the area through the remainder of the day Thursday. This will lead to the potential for more rain showers, particularly for our southeastern zones. An unsettled pattern looks to continue to take shape for Friday and into the weekend. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Rest of this afternoon...VFR. South to southwest winds around 10 knots with some local gusts 15-20 knots at times (southeast winds especially at KILG, KMIV and KACY. Moderate confidence. Tonight...VFR. South to southwest winds 5-10 knots, becoming locally light and variable. High confidence. Tuesday...VFR. Southwesterly winds 5-8 knots increasing to 10-15 knots, with some afternoon gusts up to 20 knots. Moderate confidence. Outlook... Wednesday through Thursday...Sub-VFR with rain showers and thunderstorms Wednesday afternoon and evening. Rain showers may continue into Thursday. Friday through Saturday...Sub-VFR with rain showers moving through. && .MARINE... Small Craft Advisory issued for the New Jersey Atlantic coastal waters Tuesday afternoon and Tuesday evening. Southerly flow will increase tonight and especially during Tuesday. A hot air mass will be moving over the chilly water and this vertical mixing will be reduced, however given the strength of the flow there should be a period of wind gusts to around 25 knots and seas building to about 5 feet. It looks to be more marginal for the Delaware Atlantic coastal waters and therefore held off on issuing an advisory. For Delaware Bay, the conditions should continue to remain below Small Craft Advisory criteria through Tuesday night. Outlook... Wednesday...Small Craft Advisory conditions possible. Seas lessen by Wednesday morning but elevated winds out of the southwest remain through the day Wednesday with gusts near 20-25 kt. Rain showers move in Wednesday afternoon into Wednesday night. There is also the potential for isolated thunderstorms Wednesday afternoon into early Wednesday night. Thursday...Conditions expected to be below Small Craft Advisory criteria but showers may linger. Friday through Saturday...Small Craft Advisory conditions expected as seas reach 4-6 feet. There is the chance for some rain showers. Rip Currents... This afternoon, south-southeast winds will be 10 to 15 mph with breaking waves of 1 to 2 feet. There will be a southeasterly swell with a period of around 8 seconds. As a result, there is a MODERATE risk for the development of dangerous rip currents at the Jersey Shore and a LOW risk at Delaware Beaches where winds will be more shore parallel. Tuesday, south-southwesterly winds of 10-20 mph with breaking waves of 2 to 3 feet. A southeasterly swell will remain, though the period may be slightly shorter. For now, have opted for a MODERATE risk for the development of dangerous rip currents for all NJ and DE beaches. Important to note that while surface temperatures inland will be in the upper 80s to low 90s on Monday, and low to mid 90s Tuesday, temperatures along the coasts will mainly be in the 70s to near 80 due to ocean temperatures in the 50s. These cold water temperatures can quickly cause hypothermia and physical incapacitation to anyone suddenly immersed in the water. For specific beach forecasts, visit weather.gov/beach/phi && .CLIMATE... Near record breaking temperatures are forecast from today through Wednesday. High temperatures Tuesday and low temperatures Wednesday morning could challenge monthly all time records for May. Records for our climate sites are listed below: Monthly Record High Temperatures for May Site Record/Date Allentown (ABE) 97/May 19, 1962 AC Airport (ACY) 99/May 29, 1969 AC Marina (55N) 95/May 31, 1895 & May 23, 1925 Georgetown (GED) 98/May 28, 1991 Mount Pocono (MPO) 94/May 22, 1911 Philadelphia (PHL) 97/May 30 & 31, 1991 Reading (RDG) 97/May 20, 1996 Trenton (TTN) 99/May 23, 1911 & May 31, 1986 Wilmington (ILG) 98/May 10, 1895 & May 30, 1895 Monthly Record Warmest Low Temperatures for May Site Record/Date Allentown (ABE) 71/May 31, 1975, May 28 & 31, 1991 AC Airport (ACY) 73/May 24, 2004 & May 19, 2017 AC Marina (55N) 73/May 30 & 31, 1987, & May 31, 1991 Georgetown (GED) 74/May 23, 1953 & May 20, 2019 Mount Pocono (MPO) 68/May 21, 1996 Philadelphia (PHL) 78/May 31, 1895 Reading (RDG) 72/May 28 & 31, 1939, & May 31, 1991 Trenton (TTN) 75/May 31, 1895 Wilmington (ILG) 75/May 30, 1895 Record High Temperatures May 18 Site Record/Year Allentown (ABE) 96/1962 AC Airport (ACY) 93/1987 AC Marina (55N) 90/1987 Georgetown (GED) 91/1974 Mount Pocono (MPO) 87/1962 Philadelphia (PHL) 94/1962 Reading (RDG) 96/1962 Trenton (TTN) 96/1986 Wilmington (ILG) 94/1962 Record Warmest Low Temperatures May 18 Site Record/Year Allentown (ABE) 65/2017 AC Airport (ACY) 70/2017 AC Marina (55N) 66/2017 Georgetown (GED) 72/2017 Mount Pocono (MPO) 61/2017 Philadelphia (PHL) 72/2017 Reading (RDG) 67/1900, 1943, & 2017 Trenton (TTN) 71/2017 Wilmington (ILG) 72/2017 Record High Temperatures May 19 Site Record/Year Allentown (ABE) 97/1962 AC Airport (ACY) 96/1962 AC Marina (55N) 92/1998 Georgetown (GED) 96/1962 Mount Pocono (MPO) 89/1962 Philadelphia (PHL) 96/1962 Reading (RDG) 96/1962 Trenton (TTN) 96/1962 Wilmington (ILG) 95/1962 Record Warmest Low Temperatures May 19 Site Record/Year Allentown (ABE) 65/2017 AC Airport (ACY) 73/2017 AC Marina (55N) 68/1998 Georgetown (GED) 73/2017 Mount Pocono (MPO) 60/1943 Philadelphia (PHL) 74/1877 Reading (RDG) 68/1962 Trenton (TTN) 70/2017 Wilmington (ILG) 70/2017 Record High Temperatures May 20 Site Record/Year Allentown (ABE) 92/1962 & 1996 AC Airport (ACY) 96/1996 AC Marina (55N) 93/1996 Georgetown (GED) 95/1962 Mount Pocono (MPO) 89/1996 Philadelphia (PHL) 94/1962 & 1996 Reading (RDG) 97/1996 Trenton (TTN) 94/1996 Wilmington (ILG) 96/1996 Record Warmest LowTemperatures May 20 Site Record/Year Allentown (ABE) 66/2019 AC Airport (ACY) 68/1996 AC Marina (55N) 69/1996 Georgetown (GED) 74/2019 Mount Pocono (MPO) 61/1959 Philadelphia (PHL) 71/2019 Reading (RDG) 69/1959 & 1996 Trenton (TTN) 68/1903, 1959, & 1962 Wilmington (ILG) 70/2019 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Heat Advisory until 8 PM EDT Wednesday for PAZ070-071-102-104- 106. Heat Advisory until 8 PM EDT Tuesday for PAZ060>062-101-103- 105. Air Quality Alert until midnight EDT tonight for PAZ060>062- 070-071-101>106. NJ...Heat Advisory until 8 PM EDT Wednesday for NJZ015-017>019. Air Quality Alert until 11 PM EDT this evening for NJZ001- 007>010-012-015-017>019. Heat Advisory until 8 PM EDT Tuesday for NJZ007>010. Air Quality Alert from 11 AM to 11 PM EDT Tuesday for NJZ012>021-026-027. Heat Advisory until 8 PM EDT Wednesday for NJZ012-013-020-027. DE...Heat Advisory until 8 PM EDT Wednesday for DEZ001. MD...None. MARINE...Small Craft Advisory from noon Tuesday to midnight EDT Tuesday night for ANZ450>453. && $$ DISCUSSION...Gorse/Guzzo AVIATION...Gorse/Guzzo MARINE...Gorse/Guzzo  315 FXUS62 KMHX 181901 AFDMHX Area Forecast Discussion National Weather Service Newport/Morehead City NC 301 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... No significant changes to the forecast this package. && .KEY MESSAGES... 1) Above normal to near-record high temperatures and rain-free conditions to continue through mid-week. 2) A frontal system approaches the area late week, bringing the next appreciable chance of showers and thunderstorms && .DISCUSSION... KEY MESSAGE 1...Notably warm low-level thicknesses beneath an anomalous mid-upper level ridging will continue to support above to well above normal temperatures across the Carolinas through Wednesday. Guidance shows similar low-level thicknesses each afternoon yielding highs generally in the lower 90s across the coastal plain but some warmer spots may reach mid 90s, remaining just shy of records. It will be closest across the coastal plain, however. Additionally, despite increasing low-level moisture, ridging aloft should provide sufficient subsidence to suppress convective activity outside of perhaps a rogue shower or thunderstorm where convergence is maximized along the seabreeze. Still, probs of this occuring are low enough to keep out of the forecast with this update. KEY MESSAGE 2...The mid-upper level ridge is forecast to break down some late-week and into the weekend. This should allow a front to drop south into the Thursday into Friday. There continues to be some uncertainty regarding whether or not the front fully makes it through ENC, whether it stalls, or whether it lifts quickly back north as a warm front. Given the strength of the ridge, it stands to reason that the front will struggle to get fully through ENC, and the forecast continues to reflect this scenario. Then, ridging may try to build back late in the weekend, which would favor the front lifting back north as a warm front by early next week. Based on the above, increasing moisture and instability along the frontal zone should support an increased risk of showers and thunderstorms. Probabilistic guidance shows a solid chance of 0.25"- 0.75" each day from Thursday into the weekend. However, it should be noted that those amounts will be highly dependent on the evolution of the frontal zone. Initially when the front drops into the area, there may be just enough flow aloft to support some thunderstorm organization and perhaps a marginal risk of strong to severe thunderstorms. Machine learning and analog guidance support this potential as well. However, no one day stands out as having a higher risk of severe thunderstorms. Notably high PWATs along the frontal zone should support higher rainfall rates in convection. However, notable hydro impacts are not expected due to the recent dry stretch and ongoing drought conditions. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... Pred VFR through this evening with subsidence beneith an upper ridge limiting cloud development to few-sct diurnal cu. S-SW winds generally less than 10 kt ahead of the sea breeze, then could see gusts around 15-20kt behind it this afternoon into the early evening hours. Winds become light late tonight with clear skies bringing good radiational cooling conditions and could see fog and low stratus redevelop inland late tonight. HREF probs for sub-VFR conditions currently around 40-60%. Outlook: A dry seabreeze pattern looks to continue through Wednesday. Beyond then, a frontal boundary sagging south into ENC is expected to bring an increasing risk of SHRA, TSRA, and sub-VFR conditions. && .MARINE... A summer-like pattern continues through the middle of the week, with a daily building of winds to 10-20kt each afternoon and evening as the thermal gradient tightens. This will especially be the case for the inland riversand sounds and the nearby coastal waters within 20nm of the coast. Seas will continue around 2-3ft, potentially up to 4 ft during the afternoon and evening. Outlook: A frontal boundary is forecast to sag south into the area late-week, then meander around the area through the upcoming weekend. This leads to lower confidence regarding winds and seas, but especially wind direction. In general, the risk of 25kt+ winds appears low during this time ahead of the front, with slightly higher chances of seeing 25+kt gusts behind the front. There will be an increased risk of thunderstorms along the front as well. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ DISCUSSION...SK/RJ AVIATION...SK/RJ MARINE...SK/RJ  208 FXUS63 KDVN 181900 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 200 PM CDT Mon May 18 2026 .KEY MESSAGES... - Thunderstorms are expected to hold off until mid to late evening tonight as the main severe weather threat remains tied to the cold front position well to our west this afternoon. - A mature to dissipating squall line of storms is expected to move towards our western counties later this evening, and begin to dissipate/break up as it moves eastward. - Cooler weather is expected for the mid to late week, with increasing rain chances Thursday night through Friday. && .SHORT TERM /THROUGH TUESDAY NIGHT/... Issued at 200 PM CDT Mon May 18 2026 Two areas of scattered storms and rain moved through the area early this morning, resulting in some beneficial rainfall, and extensive cloud cover over the area through this morning. The cloud cover has resulted in far less instability available for any storms over eastern Iowa this afternoon, while Illinois and Missouri continues to see over-running rains just south of our counties from the expansion of the early morning storm cluster that impacted our CWA today. This vast area of stable air should keep any prefrontal storms from forming in our CWA this afternoon and early evening. Farther west, a different story exists. Strong heat and convergence is over eastern KS, feeding into a triple point just north of Salina KS. This rather obvious spot with strongly backed winds, ample CAPE, and focusing mechanism supports supercell growth in eastern KS, southeast NE, northwest MO, and far southwest Iowa this afternoon through mid evening, as is outlined by SPC for a Moderate and Enhanced Risk. That Enh risk previously included eastern Iowa, but has been shifted west due to the late arrival time, and expectation of instability waning overnight. Various CAMs agree nearly all agree on supercells spreading east and northeast into southwest Iowa this evening, merging into a line, with bowing segments and damaging winds as is moves towards south southwest Iowa and MO. From this point going forward, convection appears to show the highest potential to split north and south, with the northern side moving towards Wisconsin and MN following the best shear and forcing, while the most significant severe weather will drop southeast from its initiation point in eastern KS to central and possibly northern MO with a significant wind threat, as well as heavy rain in MO. For our CWA, that could leave us out of the threat for severe weather, however given some threat for an organized line of storms on the northern flank of the Missouri activity, we could see a gusty squall line move from west to east over the area, as shear values will be sufficient for this to happen. In fact, if it does happen, 0-1km shear vectors could allow for some QLCS tornado potential as damaging meso vorts along the line. (if we get a coherent line overnight). Activity will be decaying regarding QPF overnight, with most rainfall expected in our southern counties once again. By early Tuesday morning, any rain will be quickly exiting our southeast CWA with a cloudy cool morning in place. Northwest winds will bring in plenty CAA Tuesday and Tuesday evening, as temperatures fall from highs in the low 60s west to mid 70s east to the 40s by mid evening Tuesday. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Issued at 200 PM CDT Mon May 18 2026 Cool high pressure looks to move in for Tuesday night through Wednesday night, resulting in lows in the 40s, but highs in the mid to upper 60s. This rather nice weather will give way to potential rain and clouds for Thursday afternoon through Friday as there is a growing signal for an upper low/deep trof passing through the Midwest inthat time frame. Pops are now increased to likely (55- 70%) for Thursday night and Friday, with some thunder possible. The clouds and showers will hold temperatures down into the 60s both days, before a warm up into the 70s and 80s spreads in for the weekend. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1228 PM CDT Mon May 18 2026 Some MVFR to VFR conditions lingering today behind earlier convection, with an expectation MVFR to low VFR deck to develop ahead of the next round of precipitation to move into late this evening/tonight. Winds have been some variable with weak influences lingering from last night's storms, but a boundary in place from southwest to northeast across Iowa to the northwest of the area that should allow for southerly flow to southwesterly flow to setup by this evening with that boundary to move through behind the storm's late tonight with winds to shift around to the west to northwest for Tuesday. Expect a band of showers/storms to spread across the area from the west/southwest late this evening into the overnight hours, with low IFR to MVFR CIGS developing behind the precipitation and boundary moving through the region into Tuesday morning. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Ervin LONG TERM...Ervin AVIATION...MJB  352 FXUS63 KMKX 181901 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 201 PM CDT Mon May 18 2026 .KEY MESSAGES... - Another round of showers and storms late tonight into Tuesday with a potential for strong to severe storms. - Cool and drier weather then returns for midweek. - Rain chances return Friday (45-55%), followed by a gradual warming trend Saturday into early next week. && .SHORT TERM... Issued 200 PM CDT Mon May 18 2026 Late this afternoon through Tuesday night: Quiet weather largely expected the rest of the afternoon into the evening with remnant convection moving off to the east with quite a bit of clearing ongoing right now ahead of developing storms to the southwest this afternoon and evening. This is what we will be monitoring tonight as it pushes into the CWA. Based on the development of this convection will in part determine how things play out tonight. Several models favor development and progression into a QLCS with a eastward progression. Most models have this potentially becoming elevated in addition to limited instability. As this pushes east toward southeast WI CAMs largely have this falling apart with very limited instability and very likely an elevated system at that point, which would reduce severe risk to essentially zero. However, it is worth mentioning that clearing this afternoon has definitely increased our severe risk as we will likely be able to hang on to a bit more instability and may avoid storms immediately becoming elevated as they reach the CWA. The best severe risk for tonight will be in southwest WI, likely southwest of Madison, with decreasing risk further east. We will need to monitor storms to the southwest tonight as the development and progression will play a role in determining the potential for severe storms later tonight. The remnant storms and precip will push out by mid morning with our attention turning to the cold front that will closely following the exiting precip. There is a mild concern for developing storms along the front but with departing storms in the morning it does not appear there will any recovery time ahead of the front with models suggesting very limited instability and frankly not a great shear environment either. This suggests that event should week storms develop they would not likely be of concern. The front should push in by the late morning and push through all of southern WI by early to mid afternoon. The best chance for weak storm development with the front is likely in southeast WI where the best chance for recovery would be. Otherwise, expect quiet conditions into the late afternoon and overnight as winds turn northwest behind the front with higher pressure gradually pushing behind it. Kuroski && .LONG TERM... Issued 200 PM CDT Mon May 18 2026 Wednesday through Monday: Cool and dry weather expected Wednesday and Thursday, with strong high pressure passing overhead and northeast to east winds off of Lake Michigan (around 10 to 15 MPH at times). Much of eastern WI should see highs in the 50s, with low to mid 60s further west. Some much needed calm and quiet weather. Our next noteworthy chance for precipitation arrives Friday, with roughly half of the available model guidance resolving a low pressure system tracking northeastward from the Great Plains and approaching our region. The favored track of this system would stall it either to our south or our west, with the continued onshore flow from Lake Michigan helping to reduce instability and prevent substantial moisture return over southern WI. Hence, we only forecast slight chances for thunderstorms Friday, with rain chances increasing from 15-55% in a southwest to northeast manner as the day goes by. As with any low pressure system this time of year, we will have to keep an eye on it's track and evolution, but ensemble consensus strongly suggests insufficient moisture return / instability for much in the way of thunder. Predictability drops substantially for Saturday and onwards, but the general consensus is a warming trend that continues into early next week. Sheppard && .AVIATION... Issued 200 PM CDT Mon May 18 2026 Conditions have quieted today with some clearing overhead right now that will gradually be impinged on today by clouds to the west. However, our attention is currently on developing convection to the southwest that will eventually track into southwest WI later tonight along with MVFR CIGS and maybe some temporarily lowered VSBYS with rain. At this time storms are not expected to be strong but there is a chances for stronger winds to linger into southwestern WI but likely weakening by the time it reaches southeast WI but some thunder could be expected all through southern WI overnight. Just after daybreak most of the rain and storms should have pushed out to the east with clouds remaining in place ahead of the front expected to come through from the late morning through early to mid afternoon. Some showers and perhaps a weak storms possible along the front but currently limited precip along the front is expected. As the front pushes through expect MVFR CIGS to clear out and likely only higher CIGS remaining behind the front. Clearing skies expected overnight. Kuroski && .MARINE... Issued 200 PM CDT Mon May 18 2026 Storms and showers are pushing out as winds behind this remain breezy from the south. These winds will increase slightly across the lake late tonight and remain breezy ahead of the cold frontal passage expected Tuesday afternoon as the low pressure system around 29.6 inches swings northeast of the Lake into Ontario. A few storms chances across primarily the south part of the lake late tonight into Tuesday morning ahead of the front. High pressure around 30.4 inches will push in behind the front with light and variable winds taking hold from late Wednesday into Thursday. Currently the northern nearshore zone is in a Small Craft for primarily wave heights to 5 feet. Winds will become breezier tonight across much of the nearshore and thus we will have an expanded Small Craft through much of Tuesday before the front Tuesday turns winds northwest and calm to a degree Kuroski && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...Small Craft Advisory...LMZ643 until 7 PM Tuesday. Small Craft Advisory...LMZ644-LMZ645-LMZ646...4 AM Tuesday to 4 PM Tuesday. && $$ Visit us at weather.gov/milwaukee Follow us on Facebook, X, and YouTube at: www.facebook.com/NWSMilwaukee www.x.com/NWSMilwaukee www.youtube.com/NWSMilwaukee  306 FXUS63 KTOP 181901 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 201 PM CDT Mon May 18 2026 .KEY MESSAGES... - Severe thunderstorms becoming numerous early to mid afternoon today and spreading east to southeast this evening. Very large hail, damaging winds, and tornadoes all quite possible. - Flash flooding remains a concern through tonight especially where heavy rain fall Sunday night. - Gusty south winds on track for the next several hours in southwestern areas. && .DISCUSSION... Issued at 200 PM CDT Mon May 18 2026 Warm, humid airmass was surging north into central Kansas ahead of a cold front toward a nearly-stationary front just northeast of northeast Kansas with a modest upper wave just upstream. Instability of 3000 J/kg already commonplace in central Kansas at 17Z with 40-50 knots of deep-layer shear. Vectors for this layer remain close to parallel to the front so there is some uncertainty in how long storms can remain discrete, but some backing of low-level flow and otherwise good setup brings all severe hazards in play. Main area of concern over the next few hours is north-central Kansas with storms spreading east and southeast and becoming more widespread with time. Threats should turn more to wind versus strong tornado in eastern areas as mode shifts to more linear. Overall a more progressive system should keep storm residence somewhat limited, but areas that saw heavy rain Sunday night will not take much more rain to experience flash flooding and intense updrafts with PW values around 1.5 inches will bring quick rainfall. Storms push southeast before dawn with flash flooding threat falling off, though rivers and creeks may be high for a few more days. Surface winds Next few days continue to look benign with modified Canadian high pressure in place with cooler temperatures. Moisture return in the mid-levels supports at least moderate precipitation chances Thursday into Thursday night but instability remains modest. A more unstable airmass should return around the holiday weekend though forcing for ascent is not readily apparent. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1223 PM CDT Mon May 18 2026 Confidence is increasing in thunderstorm potential in the 23Z-04Z window and went ahead with TEMPO inclusion. MVFR cloud should diminish soon but be more consistent after FROPA around 06Z with some chance for improvement late in the forecast. && .TOP WATCHES/WARNINGS/ADVISORIES... Flood Watch through Tuesday morning for KSZ008-KSZ009-KSZ010-KSZ011- KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026-KSZ034-KSZ035- KSZ036-KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056-KSZ058- KSZ059. Wind Advisory until 9 PM CDT this evening for KSZ035-KSZ036-KSZ037- KSZ038-KSZ054. && $$ DISCUSSION...Poage AVIATION...Poage  558 FXUS64 KLIX 181905 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 205 PM CDT Mon May 18 2026 ...New SHORT TERM, LONG TERM, MARINE... .KEY MESSAGES... Updated at 132 PM CDT Mon May 18 2026 - Showers and thunderstorms will become more numerous and widespread Wednesday through the weekend. 7 day rainfall totals will range from 4 to 7 inches in the northwest to less than an inch of much of coastal MS and extreme SELA. - Minor coastal flooding may slightly impact typically known problem areas like Waveland, MS tomorrow and Wednesday around midday. - Temperatures are forecast to be generally near to warmer than normal through the next 7 days. && .SHORT TERM... (Now through Tuesday night) Issued at 132 PM CDT Mon May 18 2026 We are seeing isolated to widely scattered showers over the area, mainly along and north of the 10/12 corridor. this activity should quickly come to an end as the sun begins to set. As for tomorrow, rain chances may be a tad higher but overall Tuesday will be fairly similar to today. We will likely still have enough ridging in place to keep convection down to isolated to widely scattered but as the week continues convection will increase in coverage. Biggest positive from a rain chance stand point will be the moisture increase. Moisture is already slowly increasing but we will see Pws surge tomorrow. If rain remains on the lower end tomorrow and clouds aren't too thick, it will be a warm day. h925 temps of 23-24 C suggest highs around 90 to lower 90s. But given the likelihood of broken skies we probably wont fully realize those temps but upper 80s to maybe a few locations touching 90 will be possible. One more possible impact tomorrow could be minor coastal flooding in some of the common problem areas. We are right at Spring tide for the month and given the persistent light to moderate onshore flow we are running around 0.6 to just under 1' above astronomical and that will be the case for atleast one more day tomorrow. /CAB/ && .LONG TERM... (Wednesday through Sunday night) Issued at 132 PM CDT Mon May 18 2026 Medium range models are in rather good agreement with southwest flow remaining over the area through the forecast. Obviously specific timing of impulses and rainfall amounts differ but the overall setup is no different. NBM is advertising numerous to categorical PoPs starting Wednesday and each day through the weekend and without being able to get very specific with timing see no reason to deviate from it. Southwest flow finally gets strong enough to push the ridging aloft to the east and the first in a series of impulses is expected to push through the region. Timing of it specifically is still too difficult to pin point at this time. Moisture already having increased with PWs at or just below 2" will be in place. We will likely see quite a bit more activity Wednesday afternoon and into the evening than we have the previous 5 days, mainly across the northwest. The southeastern half of the CWA could remain mostly dry as the ridge could still have enough of an impact over these locations. Heading into Thursday and through the weekend things only improve for rain potential over the northwestern 2/3rds of the CWA. Southwest flow will remain in place through this time. There will be no front plowing through or trough axis sliding completely across the region thus leaving a moisture abundant atmosphere in place. In addition there will be persistent diffluence aloft as the ridging to our east will try to induce split flow in the upper levels right over the region. That, unstable conditions, and the abundant moisture in place will aid the efficiency of storms and rainfall could begin to quickly add up over some of the northwest. Locations along extreme SELA and much of coastal MS on the other hand may struggle to get more than an inch of rain over the next 7 days. /CAB/ && .AVIATION... (18Z TAFS) Issued at 1228 PM CDT Mon May 18 2026 A lot of cu out there leading to multiple terminals in MVFR status with cigs ranging from 1100 to just over 2k ft. Vsbys are good and should remain fine through the forecast. There are a few -SHRA out there mainly in some confluent zones but overall the activity is fairly isolated. Those will quickly weaken around sunset and winds will weaken inland overnight as well. Biggest impact through the remainder of today and overnight will be in the form of low cigs leading to many terminals dropping to/maintaining MVFR status likely seeing some improvements just after sunrise. /CAB/ && .MARINE... Issued at 132 PM CDT Mon May 18 2026 A large area of high pressure will remain situated over the western Atlantic through the week and into the weekend. This will maintain light to moderate onshore flow through the time. Winds will bounce around headline criteria over the next 24 to 36 hours with sustained winds right around 15 kts, especially closer to the coast. Exercise Caution headlines will be in effect again overnight for the waters west of the mouth of the river along with Breton and Chandeluer Sound. As for showers and thunderstorms daily isolated to scattered light showers will be possible each day however the bull of the coverage will remain inland. With any thunderstorm locally hazardous winds and waves can be expected. One last hiccup is maybe some very minor coastal flooding impacts, mainly around the Waveland area given the high astronomical tides and persistent southerly winds. Tuesday midday may be the peak of any tidal impact's. /CAB/ && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...CAB LONG TERM....CAB AVIATION...CAB MARINE...CAB  644 FXUS63 KDLH 181906 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 206 PM CDT Mon May 18 2026 .KEY MESSAGES... - Another night with showers and storms possible. Severe risk has decreased and is now isolated to southeast portions of our CWA. Primary threats would be damaging winds and large hail. - Freeze Warning likely needed across most the region for Tuesday night. - Cool temps through midweek with a warming trend into the weekend. && .DISCUSSION... Issued at 155 PM CDT Mon May 18 2026 Current Conditions/Today: Widespread stratus has engulfed most the region in the wake of last nights showers and isolated storms. We are also seeing some areas of fog from the Brainerd Lakes Region and extending northeast through the Twin Ports and up the shore. This layer of stable air will keep temperatures cool with highs staying in the 50s under this cloud deck. Satellite is showing a few pockets of clearing over SE MN and western WI where temperatures will rebound back into the 70s helping to reload instability for this evenings convective potential. However, up in our portion of NW WI there are few breaks in the clouds with low clouds still filtering in from the west, so recovery seems limited. A baroclinic zone will still be draped across the Upper Midwest this afternoon with a surface low pressure centered over SE MN. Through the evening and overnight hours several low pressure systems will ride along this boundary boosting lift and helping to fuel shower and storm development. However, satellite trends through the morning hours have not been favorable for instability recovery and our temperatures across the region remain quite cool when compared to our neighbors to the south. The main threat for severe weather will be well off to our south. As such the SPC has pulled the severe risk down to just our SE corner with a marginal risk. Some strong storms can't be ruled out at this time with some damaging winds and hail at times, but the tornado chances are no longer a concern. Showers are expected to become more widespread later this evening. The two focal points for this activity is the low pressure moving along the stalled boundary and an upper level trough pivoting across the Upper Midwest. Targeted timing for rain entering from the southwest is after 9PM with activity departing to the northeast after 8AM. With the reduced risk for thunderstorms our overall rain totals have come down a bit with most the region seeing between 0.10-0.25" Areas that do see thunderstorms will have locally higher amounts, but the overall risk for flooding has diminished. Tuesday/Wednesday/Thursday: Northwest flow and surface high pressure builds in from the west on Tuesday. Cyclonic flow aloft paired with remnant moisture will lead to diurnally driven cumulus and isolated sprinkles across northern MN. Temperatures will be on the cool side for Tuesday with highs in the 40s and 50s. Overnight, the high pressure moves over MN with clear skies leading to rapid radiational cooling. Widespread Freeze Warnings will likely be needed across the region. Conditions dry out a bit more on Wednesday with high temps rebounding back into the 50s and 60s. Winds will be light so fire weather concerns are low at this time. By Thursday high pressure departs to the east and we will get southerly return flow streaming back into the region. High temps will continue to climb back into the upper 60s with cooler conditions expected by Lake Superior. Friday-Weekend: An upper level trough is still expected to move across the Northern Plains to end the work week bringing rain chances back to the Northland. Timing of this has been slowed down when compared to previous model runs with 20-30% PoPs now entering Friday afternoon.This will also prompt the return of southwest flow aloft leading to a warming trend. Weekend temperatures in the 70s and some 80s possible with cooler by the Lake still in play. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1223 PM CDT Mon May 18 2026 Widespread IFR/LIFR stratus clouds engulf most of the region this afternoon with a surface low over SE MN. Ceilings are not expected to improve through the day as a baroclinic zone is laid across the Upper Midwest. Later this evening showers and some storms are expected to develop and move northeast through the region. This activity will move off to the northeast tomorrow morning with gusty northwest winds filtering in behind. Ceilings may be slow to improve tomorrow. && .MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 155 PM CDT Mon May 18 2026 Light winds currently across the Lake. These winds will increase out of the northeast this evening with Small Craft Advisories in effect. Winds will turn to out of the northwest Tuesday afternoon and weaken. Additionally, a few showers and storms are possible tonight through tomorrow morning. For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt. && .FIRE WEATHER... Issued at 155 PM CDT Mon May 18 2026 Cloudy today with high Min RHs. Another batch of showers and a few storms are expected to roll over the region the region tonight and exit tomorrow morning. Rain totals have trended down with most areas expected to see between 0.10-0.25" Areas that do get thunderstorm development can expect locally higher amounts. Gusty northwest wind for Tuesday paired with virga and sprinkles in the afternoon. Next dry day will likely be Wednesday, winds will be light though as high pressure moves over the region. See the Fire Weather Forecast product for a more thorough breakdown of fire weather conditions. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. MARINE...Small Craft Advisory from 9 PM this evening to 1 PM CDT Tuesday for LSZ140>143. Small Craft Advisory from 11 PM this evening to 9 AM CDT Tuesday for LSZ144-145. Small Craft Advisory from 11 PM this evening to 11 AM CDT Tuesday for LSZ146-147. Small Craft Advisory from 9 PM this evening to 3 PM CDT Tuesday for LSZ148-150. && $$ DISCUSSION...Britt AVIATION...Britt MARINE...Britt FIRE WEATHER...Britt  752 FXUS62 KKEY 181908 AFDKEY Area Forecast Discussion National Weather Service Key West FL 308 PM EDT Mon May 18 2026 ...New AVIATION... .KEY MESSAGES... - Very warm and humid conditions over the next few days will lead to a generally moderate risk of heat illness with periods of high risk conditions. - Rain and thunder chances will remain on a plateau through tomorrow, and gradually decline thereafter. - A period of on and off breezy conditions over the next few days will help to mitigate some of the discomfort from warm overnight temperatures. && .AVIATION... (18Z TAFS) Issued at 302 PM EDT Mon May 18 2026 VFR conditions will prevail at both island terminals, but occasional observations of MVFR CIGs are possible as pockets of showers continue to move through the area. Due to low confidence related to location and timing of impactful showers, opting to carry VCSH in the TAF package. Amendments will be made if necessary. East surface winds near 15 knots will prevail. && .PREV DISCUSSION... Issued at 440 AM EDT Mon May 18 2026 Additional moisture to our east should pivot in throughout the rest of today. This combined with an already accelerated flow, should help to smash any mesoscale boundaries out there, allowing for showers to increase in coverage again. This enhanced moisture pool will linger through tonight and gradually begin scouring out starting Tuesday. This will not be a fast process and rain chances will be slow to diminish through the week. Meanwhile, a high pressure near Bermuda will flatten over the next several days, weakening the pressure gradient through the end of the week. This will lead to generally a slackening of winds, though there will still be some peaks in the evenings at times. By the end of the week we may have an easterly undulation move through the Bahamas and along the east coast of Florida, injecting more moisture back across the area, and subsequently rain chances. It's too far out to get our hopes up at this time. && .MARINE... Issued at 1130 AM EDT Mon May 18 2026 Surface high pressure centered near Bermuda will continue to promote moderate to fresh east to southeast breezes through the next couple of days. Highest breezes will prevail through Tuesday evening. Breezes then undergo a very slow slackening process with peaks expected during the evenings and lulls during the day. Rain and thunder chances will remain above normal through much of the week. && .PRELIMINARY POINT TEMPS/POPS... Key West 80 91 80 90 / 40 40 30 20 Marathon 79 86 80 86 / 40 40 30 20 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...DP Aviation/Nowcasts....DP Data Acquisition.....DP Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest  168 FXUS63 KDDC 181912 AFDDDC Area Forecast Discussion National Weather Service Dodge City KS 212 PM CDT Mon May 18 2026 .KEY MESSAGES... - Strong to severe thunderstorm chances (50-70%) pick up across south central Kansas late afternoon through early evening. - Unseasonably cool temperatures arrive tonight and stick around through at least Wednesday. && .UPDATE... Issued at 212 PM CDT Mon May 18 2026 ***MESOSCALE DISCUSSION*** Current satellite depicts cumulus development ahead of a boundary stretching from Meade northeastward into Pawnee and Stafford Counties. A few convective attempts have already started, with the primary deep convection more northeast of the area in central Kansas. A brief landspout could occur on any initial development given the strong surface vorticity, steep low-level lapse rates, and stationary nature of the boundary. After around 3-4 PM, convective evolution should transition to more robust storms down and along this boundary. Per mesoanalysis, effective bulk shear of 45-55 knots and MLCAPE of 3000-4000 J/kg suggests supercells. Damaging winds, very large hail, and a tornado risk is expected to materialize, especially as low-level shear increasing into the evening. The ultimate extent of significant severe weather will be contingent on if activity can stay more discrete. The ceiling is high for significant impacts, but trends will be monitored in the coming hours. && .DISCUSSION... Issued at 134 PM CDT Mon May 18 2026 WV imagery indicates a closed upper low pushing east through eastern Utah into western Colorado. Near the surface, a quasi-stationary frontal boundary extends from the eastern Texas Panhandle northeastward through northwest Oklahoma into south central Kansas. Another round of thunderstorms (50-70% chance) are expected to develop across central/south central Kansas late today as the SREF indicates an embedded upper level shortwave within a larger scale trough quickly cycling northeast through the Colorado Rockies this afternoon, and farther up into the Upper Midwest this evening. In response, a quasi-stationary frontal boundary is forecast to move very little through early evening before being dislodged southward by a secondary frontal boundary surging in from the north. Ample moisture pooling south of the boundary with surface dewpoints well up into the mid/upper 60s(F) to near 70F will provide significant instability with MUCAPE values in excess of 4000 J/kg. Despite a less than robust southwest flow aloft (<50kt), thunderstorm development is likely late this afternoon as the core of the upper level shortwave passes just to our northwest in conjunction with a weakening cap as low/mid-level lapse rates steepen from peak daytime heating. The HREF supports this showing a 20-40% probability of 6-hr QPF exceeding 0.25 of an inch across south central Kansas, generally southeast of a Larned to Minneola line by late this evening. Strong instability and favorable deep layer shear will increase severe potential, including large hail and possibly a tornado or two. Drier conditions will then take hold through at least early Wednesday with drier air spreading southward into western Kansas while surface high pressure shifts eastward across the Dakotas into the Upper Midwest. Unseasonably cool temperatures are forecast tonight as much cooler air surges southward into western Kansas behind a cold front pushing through western Kansas into northern Oklahoma early/mid-evening, dropping the H85 5C isotherm well down into extreme southwest Kansas. With the HREF painting a 70-90% probability of temperatures dipping below 45F across the region in question to a 30-50% probability of temperatures falling below 50F in south central Kansas, expect lows generally down into the 40s(F) with the upper 30s(F) possible out near the Colorado line. Temperatures remain below normal Tuesday as surface high pressure in the Upper Midwest helps reinforce a the cooler air mass across western Kansas within an easterly upslope flow with H85 temperatures ranging from around 10C in central Kansas to near 15C in extreme southwest Kansas. Considering the HREF shows a 70-90% probability of temperatures topping 65F in west central/central Kansas to a better than 90% probability of exceeding 65F farther south near the Oklahoma line, look for afternoon highs mainly in the 60s(F). Similar temperatures are likely Wednesday under the influence of a prevailing easterly upslope flow. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1100 AM CDT Mon May 18 2026 IFR cigs are expected to linger in vicinity of KHYS through mid- afternoon as prevailing low level stratus continues to erode slowly northward, then return to VFR the remainder of the afternoon as the stratus scatters out. Otherwise, primarily VFR conditions will persist in vicinity of KLBL, KDDC, and KGCK through early Tuesday. Thunderstorm development is likely along and ahead of a warm front projected to advance northward across south central Kansas late this afternoon through early evening. However, storms are expected to remain east of a KHYS to KDDC line. Light north-northeast winds will persist across west central and portions of southwest Kansas north of a quasi-stationary frontal boundary extending from the eastern Texas Panhandle northeast into south central Kansas. Meanwhile, southerly winds around 15 to 25kt with gusts up to 35kt will continue across south central Kansas into eastern portions of southwest Kansas south of the boundary through early evening. North winds around 15 to 25kt with gusts up to 30kt are forecast to develop generally after 23-01Z behind a cold front pushing southward through western Kansas this evening. && .DDC WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 9 PM CDT this evening for KSZ074>078- 084>088. && $$ UPDATE...Bennett DISCUSSION...JJohnson AVIATION...JJohnson  386 FXUS61 KAKQ 181916 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 316 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... No significant changes to the forecast. SPC continues to outlook northern portions of the area in a Marginal Risk (level 1 of 5) for severe storms Wednesday afternoon and evening. && .KEY MESSAGES... 1) Remaining hot and dry, with well above normal temperatures continuing through Wednesday. Rain chances increase Wednesday night ahead of an approaching cold front. Best rain chances late Wednesday remains over northern portions of the area. 2) An increasingly unsettled and cooler pattern looks to evolve for the late week period with more uncertainty in temperatures over the Memorial Day Weekend. && .DISCUSSION... As of 315 PM EDT Monday... KEY MESSAGE 1...Remaining hot and dry, with well above normal temperatures continuing through Wednesday. Rain chances increase Wednesday night ahead of an approaching cold front. Best rain chances late Wednesday remains over northern portions of the area. Building ridging and minimal low-level moisture should lock in a summer-like heat and continued dry conditions for the first half of the week. Temperatures are currently in the lower 90s across the area with some upper 80s along the coast. Widespread lower to mid 90s are expected through Wednesday. Temperatures will be similar each day, perhaps increasing a degree or so each day, culminating with the warmest day of the week on Wednesday. The strong mixing and dry antecedent conditions will continue to allow early morning dewpoints to mix out by afternoon, and fall back into the upper 50s to low 60s each day. This will keep heat indices close to actual air temps, as well as dry conditions into Wednesday afternoon. Then Wednesday afternoon, a cold front will approach the area and showers and storms could develop from the pre-frontal trough. The latest models continue to show any convection only reaching north and west portions of the area, likely staying out of the RIC metro. SPC has included northern portions of the area, including RIC metro, in a Marginal Risk (level 1 of 5) with the potential of damaging winds and large hail. The risk of severe storms looks to be marginal with the concern of storms dissipating before reaching the area, but nonetheless, still possible. KEY MESSAGE 2...An increasingly unsettled and cooler pattern looks to evolve for the late week period with more uncertainty in temperatures over the Memorial Day Weekend. A shortwave trough is progged to lift across the upper Midwest into eastern Canada Wednesday into Thursday. This will serve to dampen to SE ridge, while also allowing cool high pressure to settle over the Great Lakes and SE Canada. The cold front will push south of the area Thursday and Friday, leaving a CAD wedge setup with highs in the 60s to 70s with cloudy, drizzly conditions. Then on Saturday, the wedge airmass will erode, pushing a warm front back through the area with temperatures return back to near normal. Some additional isolated to scattered showers and a few storms are possible Sat/Sun, but by no means does the holiday weekend look to be a washout. Rainfall totals for the week do not look like the drought buster we need, with ensemble guidance showing a mean of only 0.50-1.00" for the week. Will note that with recent systems, the ensembles were quite bullish with precip totals and widely over-estimated multiple days out. Gradual warming is expected as we head into early next week, as mid-level ridging rebuilds east of the Rockies early next week. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... As of 150 PM EDT Monday... VFR conditions prevail through the 18z/18 TAF period as high pressure remains dominant offshore. SCT-BKN cumulus clouds have developed over the southeast, but otherwise SKC skies across the area. SW winds are currently ~10 kt, with gusts up to 20 kt at RIC and SBY this afternoon. Winds will become more southerly overnight, remaining ~10 kt. Outlook: VFR conditions expected through midweek, as high pressure remains in control. South/southwest winds each afternoon may gust to 15-20 kt each day through Wednesday. The next chance of rain and possible degraded flight conditions isn't expected until late Wednesday or Thursday. && .MARINE... As of 240 AM EDT Monday... Key Messages: - Mainly Sub-SCA conditions are expected across the local waters through at least mid-week with primarily southerly winds. - A front moves through late week, bringing the next chance at SCA conditions. Expansive high pressure remains parked across the western Atlantic and extends across the Southeast. Winds remain out of the SW at generally 10 to 15 kt across the local waters. Seas are 2-3 ft across the coastal waters and 1 ft or less in the Bay and rivers (1- 2 ft at the mouth of the Bay). Through mid-week, high pressure will remain parked across the western Atlantic in a typical summertime Bermuda High configuration. Winds remain primarily SSW around 10 to 15 kt outside of the daily mid to late-afternoon nearshore seabreeze. The afternoon breeze will likely bring additional localized gusts of 15-20 kt to the lower Chesapeake Bay and nearshore ocean waters each afternoon before winds veer back offshore and diminish through the overnight. These surges will be relatively brief and likely will not require any SCAs. Expect generally benign marine conditions to prevail through at least midweek. The next cold front looks to cross the waters some time early Thursday morning with increasing NE winds late week. At this time, in-house wind probs suggest that even behind the front, only brief marginal SCA conditions are possible and conditions may stay under SCA criteria through next weekend. Whether or not the aforementioned front actually moves through or stalls across the area will play an important role in the wind regime late week into the weekend. && .CLIMATE... As of 145 AM Monday... Record High Temps for 5/18 - 5/20 Record Record Record High/Year High/Year High/Year Location 5/18 5/19 5/20 -------- ---- ----- ------ Richmond 95 (1962) 97 (1962) 97 (2022) Norfolk 95 (1877) 96 (1880) 98 (1996) Salisbury 96 (1911) 97 (2011) 98 (1911) Eliz. City 93 (1987) 95 (1996) 98 (1996) Record High Min Temps for 5/18- 5/20 Record Record Record High High High Min T/Year Min T/Year Min T/Year Location 5/18 5/19 5/20 -------- ---- ----- ------ Richmond 72 (2015) 71 (1997) 71 (2018) Norfolk 75 (1995) 72 (2017) 73 (1996) Salisbury 71 (1953) 70 (1929) 70 (2018) Eliz. City 73 (1995) 72 (2018) 73 (2018) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ DISCUSSION...KMC/MAM AVIATION...KMC/MAM MARINE...AJB/NB CLIMATE...MAM  494 FXUS61 KCLE 181919 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 319 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... The Slight Risk for Tuesday has been expanded to include nearly the entire forecast area. Otherwise, no significant changes were made with this forecast package. && .KEY MESSAGES... 1) The hottest temperatures of the year thus far will continue through Tuesday. The heat will break behind a cold front on Wednesday with below normal temperatures continuing into Thursday. 2) A few strong to severe thunderstorms are possible in Northwest Ohio and possibly close to the lakeshore this afternoon into early this evening. Another round of strong to severe storms is possible on Tuesday afternoon and evening. 3) Unsettled weather with periods of rain expected and thunderstorms possible over the holiday weekend. && .DISCUSSION... KEY MESSAGE 1... Deep warm air advection will remain in place across the area over the next couple of days, resulting in above normal to near record temperatures across the area through Tuesday. Temperatures will remain in the 80s to around 90 degrees through the remainder of this afternoon with temps into the upper 60s and lower 70s tonight. Temperatures will decrease a bit faster in locations that receive rain (most likely NW OH) this afternoon. Temperatures will once again rise into the 80s and possibly touch 90 degrees Tuesday afternoon, although confidence in temps reaching the upper 80s and lower 90s (and possibly touching record values) is slightly lower than today due to low- end chances of morning showers, afternoon convection, and increased cloud cover. Dew points will likely be a bit higher on Tuesday afternoon so it will definitely feel muggy. Those spending time outside this afternoon and during the day Tuesday should wear light/loose-fitting clothing and hydrate and sensitive groups should consider limiting time outdoors during peak heating. Temperatures will cool down for mid to late week with highs in the 60s expected Wednesday and Thursday. KEY MESSAGE 2... As of 230 PM EDT, a line of severe thunderstorms was moving east across Indiana. There is a very tight instability gradient that ends just within the western fringe of the local area so anticipate storms to quickly weaken as they encounter less instability later this afternoon and early this evening. Nonetheless, isolated to scattered strong to severe storms are possible, especially in the Slight Risk (level 2 of 5) area that's in place across the Toledo area as the storms move in over the next couple of hours. Isolated stronger storms are possible in the northern portion of the area where there is a Marginal Risk (level 1 of 5) of severe weather. Damaging wind gusts will be the main threat, however large hail is possible and a quick spin-up can't be ruled out in the Slight Risk area. Once convection weakens this evening, scattered showers may persist across NW OH through the overnight hours with low-end PoPs expanding east across the local area Tuesday morning. The moist, unstable air mass will remain in place over the area on Tuesday, especially if the forecast trends drier and sunnier than currently forecast. MLCAPE values will likely exceed 2000 J/kg by peak heating Tuesday with effective bulk shear values likely increasing to 30+ knots as a cold front advances east towards the area Tuesday afternoon. Scattered showers and thunderstorms are likely Tuesday afternoon into Tuesday evening, although there's some uncertainty in the placement of convective initiation and exact timing of thunderstorms. Thunderstorm development will likely rely on early day cloud cover and any showers that develop Tuesday morning. Given the instability and shear profile, storms may be strong to severe and there is a Slight Risk (level 2 of 5) of severe weather across nearly the entire area. Damaging wind gusts will be the primary concern, but some storms may produce large hail. A few tornadoes cannot be ruled out. KEY MESSAGE 3... A period of dry weather is expected Wednesday through Thursday before precipitation chances increase Friday through the holiday weekend as weak low pressure and a frontal boundary slowly drift north across the Ohio Valley. There's still quite a bit of uncertainty in the timing and coverage of showers (and possibly a few thunderstorms) over Memorial Day Weekend, but at the moment it looks like the best chances of precipitation will occur Friday night and Sunday into Monday. Confidence in the likelihood of hazardous weather is low this far out, but will continue to monitor trends in guidance and adjust the forecast/key messages as necessary. && .AVIATION /18Z Monday THROUGH Saturday/... All eyes will be on the line of convection currently marching through Indiana as of 1730Z. Expect this to move into northwest OH over the next few hours with strong storms expected and gusts at the TOL/FDY terminals, but then should weaken fairly rapidly as it continues eastward. Will include TSRA at CLE and MFD as this line of convection deteriorates, but not any further eastward. Winds southwesterly will gust to 30kts. May ease a bit overnight, and at TOL/FDY where the low level jet is more pronounced, LLWS possible tonight. Southwesterly winds gusting to 30kts continues again Tuesday, and expect another round of convection to develop, but affects for our area will lie just beyond the forecast period/18Z Tuesday. Outlook...Non-VFR likely at times in showers/thunderstorms Tuesday into Wednesday. Non-VFR possible in showers on Friday. && .MARINE... Southwest/offshore winds 15-25kts through Tuesday and wave heights increasing rapidly away from shore with 1-3ft in the nearshore zones and 2-4ft in the open water zones. A cold front comes through Tuesday night with northerly winds 10-15kts through Wednesday, increasing to 15-20kts out of the northeast Thursday and 2-4ft waves for the central and western basins. Winds become light and variable into the weekend. && .CLIMATE... High temperatures today and Tuesday will approach record values. The following are the records for May 18 and 19 at local climate sites. Date Toledo Mansfield Cleveland Akron Youngstown Erie 05-18 95(1962) 92(1962) 91(1962) 92(1962) 92(1962) 89(1889) 05-19 92(1996) 88(1964) 88(1998) 91(1911) 89(1934) 90(1996) && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ DISCUSSION...15 AVIATION...26 MARINE...Sullivan  510 FXUS64 KJAN 181919 AFDJAN Area Forecast Discussion National Weather Service Jackson MS 219 PM CDT Mon May 18 2026 ...New DISCUSSION... .KEY MESSAGES... - Isolated severe storms are possible in the northwest Tuesday evening. - Heat and humidity more typical of early summer can be expected along with increasing thunderstorm chances this week into the weekend. && .MESOSCALE UPDATE... Issued at 1218 PM CDT Mon May 18 2026 Rest of today and tonight... The region remains on the western periphery of subtropical ridge parked just east of the Atlantic seaboard and amplified mean troughing, with the center over the Rockies. The cold core and attendant surface low/frontal system will eject into the northern Plains to Great Lakes region tonight. With warm/moist advection (thermal profiles at 850mb in the mid to upper teens and PWs of 1.5 to 1.75 inches along and west of Interstate 55), increased cloud coverage and isolated to scattered rain and storm chances will be possible across southern to southwest MS and northeast LA this afternoon into early evening. GOES East and observed soundings to the east indicate drier thermal profiles (1.0 to 1.2 inch PWs), so rain chances should remain low to non-existent. Seasonable warmth is expected today, some 4F to 8F above (highs: 86F to 91F). Thermodynamic parameters remain sufficient (7.0 deg C mid level lapse rates;25C to 28C vertical totals; MLCAPE (800-1200J/kg) and SBCAPE (1200-2000J/kg). Deep shear (20 to 25kts) that could support some strong storms in the west this afternoon to evening but confidence in severe storms remains low. This has a feel of a typical diurnal summertime storm afternoon, but a rogue multicell storm or microburst cannot be ruled out. Return flow of low level moisture will bring some low clouds and visibility reductions. Probabilities remain low for dense fog and some light wind will be present. Thus, no mention is needed in HWO just patchy visibility reductions in the Pine Belt by daybreak. Forecast was shipped out earlier. Lows will be seasonably warm, some 10F to 15F above (70F to 72F east of I-55 to 73F to 75F along and && .DISCUSSION... Issued at 219 PM CDT Mon May 18 2026 Rest of the week into weekend (Tuesday through Sunday)... Longwave trough will be ejecting into Canada and Hudson Bay region. Persistent summertime pattern of seasonable warmth (4F to 8F above and highs in 88F to 92F) and moisture (forecasts of 1.5 to 1.9 inches) will be the norm. Diurnal shower and thunderstorm activity will be a concern ahead of a few perturbations in the southwesterly flow (20 to 55 percent) and increased heat and humidity. With some steep lapse rates (vertical totals near 27C to 29C), some strong to isolated severe storms remain possible Tuesday and into mid week. There is anticipated of afternoon development in the Plains should sink southeast into the Ozarks in the evening and make it into the area by late afternoon into early evening. Storm mode is a question but even a southeast traversing cold pool could initiate some strong to isolated severe thunderstorm activity into Tuesday evening. While there could be some diurnal activity between 3-5PM, the concern for severe storms will be mainly after 6PM and last until just after midnight. The ongoing HWO graphic remains valid, but the timing has been slowed down into the evening to just after midnight (6PM Tuesday through 2AM Wednesday). Deep flow/bulk shear will be light (15-25kts) and variable and storm organization will need to be in tandem to the southwesterly low level flow. This could hinder any southeastward propagating MCS, which is alluded to in some convective allowing model (CAMs) output. With generally southerly to southwesterly flow in the low levels, cold pools may eventually get out of balanced and more cold pool dominant, decreasing the severe potential closer to Interstate 55 and central portions of the area closer to or just after midnight. Damaging wind gusts and hail remain the main concerns. As a stronger wave swings into the Great Lakes and surface low ejects into eastern Canada (995mb to 1000mb), front will shift south southeast towards the Gulf states. Several perturbations will enhance upper diffluence, increasing ascent and moisture advection. This will drive higher coverage of rain and storms (45 to 90 percent Wednesday and Thursday). High temperatures will be seasonable (mid to upper 80s Wednesday to low to mid 80s rest of the week) with lows less seasonable, from 8F to 12F above (upper 60s to low 70s). With less seasonable temperatures, humidity and lapse rates, some stronger storms are likely and marginally severe storms remain possible. Mid to deep layer bulk shear will remain sufficient (around 30kts), with low level shear around 15-25kts. This will keep potential marginally severe concerns through the remainder of the work week (Wednesday through Friday). Rain totals for the week will be around a couple of inches (1 to 3 inches), which will help lessen some long term drought concerns. Large scale synoptic pattern (i.e. southwesterly return flow, warm advection, high PWs near 2 inches) will persist, keeping rain chances high late week into the weekend (70 to 90 percent Friday through Sunday). Some low end severe potential cannot be ruled out, but lower severe probs and less heat and shear juxtaposed will keep mention of anything in HWO on a day-to-day basis, each day dependent on previous day's storm evolution. Rain totals will add up (additional one to three inches, with storm total rain through the weekend of 4 to 6 inches), continuing improvements to long term drought concerns. /DC/ && .AVIATION... (18Z TAFS) Issued at 1218 PM CDT Mon May 18 2026 VFR flight categories will prevail at area TAF sites this afternoon and into this evening. An isolated thunderstorm or two can't be ruled out during the late afternoon hours, but these will quickly dissipate around sunset. If observed on-site, a reduction in flight categories to MVFR/IFR status will be possible. Another bout of MVFR/IFR ceilings will be possible at sites mainly along south of the Interstate 20 corridor early Tuesday morning, with a reduction of visibilities to MVFR/IFR status around day break due to patchy fog at namely KPIB and KHBG. Through Tuesday morning, categories will steadily improve to VFR status as both patchy fog and low stratus erode. Breezy southerly winds will subside a bit this evening to between 3-8 knots. /19/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 73 89 71 86 / 10 30 40 60 Meridian 71 90 70 88 / 10 20 20 30 Vicksburg 74 90 70 85 / 10 40 50 80 Hattiesburg 72 89 69 88 / 0 20 10 50 Natchez 75 90 71 86 / 20 50 60 80 Greenville 74 91 71 83 / 10 40 60 90 Greenwood 75 91 71 85 / 20 30 60 90 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ DC/19  542 FXUS61 KAKQ 181920 AFDAKQ AREA FORECAST DISCUSSION National Weather Service Wakefield VA 320 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... No significant changes to the forecast. SPC continues to outlook northern portions of the area in a Marginal Risk (level 1 of 5) for severe storms Wednesday afternoon and evening. && .KEY MESSAGES... 1) Remaining hot and dry, with well above normal temperatures continuing through Wednesday. Rain chances increase Wednesday night ahead of an approaching cold front. Best rain chances late Wednesday remains over northern portions of the area. 2) An increasingly unsettled and cooler pattern looks to evolve for the late week period with more uncertainty in temperatures over the Memorial Day Weekend. && .DISCUSSION... As of 315 PM EDT Monday... KEY MESSAGE 1...Remaining hot and dry, with well above normal temperatures continuing through Wednesday. Rain chances increase Wednesday night ahead of an approaching cold front. Best rain chances late Wednesday remains over northern portions of the area. Building ridging and minimal low-level moisture should lock in a summer-like heat and continued dry conditions for the first half of the week. Temperatures are currently in the lower 90s across the area with some upper 80s along the coast. Widespread lower to mid 90s are expected through Wednesday. Temperatures will be similar each day, perhaps increasing a degree or so each day, culminating with the warmest day of the week on Wednesday. The strong mixing and dry antecedent conditions will continue to allow early morning dewpoints to mix out by afternoon, and fall back into the upper 50s to low 60s each day. This will keep heat indices close to actual air temps, as well as dry conditions into Wednesday afternoon. Then Wednesday afternoon, a cold front will approach the area and showers and storms could develop from the pre-frontal trough. The latest models continue to show any convection only reaching north and west portions of the area, likely staying out of the RIC metro. SPC has included northern portions of the area, including RIC metro, in a Marginal Risk (level 1 of 5) with the potential of damaging winds and large hail. The risk of severe storms looks to be marginal with the concern of storms dissipating before reaching the area, but nonetheless, still possible. KEY MESSAGE 2...An increasingly unsettled and cooler pattern looks to evolve for the late week period with more uncertainty in temperatures over the Memorial Day Weekend. A shortwave trough is progged to lift across the upper Midwest into eastern Canada Wednesday into Thursday. This will serve to dampen to SE ridge, while also allowing cool high pressure to settle over the Great Lakes and SE Canada. The cold front will push south of the area Thursday and Friday, leaving a CAD wedge setup with highs in the 60s to 70s with cloudy, drizzly conditions. Then on Saturday, the wedge airmass will erode, pushing a warm front back through the area with temperatures return back to near normal. Some additional isolated to scattered showers and a few storms are possible Sat/Sun, but by no means does the holiday weekend look to be a washout. Rainfall totals for the week do not look like the drought buster we need, with ensemble guidance showing a mean of only 0.50-1.00" for the week. Will note that with recent systems, the ensembles were quite bullish with precip totals and widely over-estimated multiple days out. Gradual warming is expected as we head into early next week, as mid-level ridging rebuilds east of the Rockies early next week. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... As of 150 PM EDT Monday... VFR conditions prevail through the 18z/18 TAF period as high pressure remains dominant offshore. SCT-BKN cumulus clouds have developed over the southeast, but otherwise SKC skies across the area. SW winds are currently ~10 kt, with gusts up to 20 kt at RIC and SBY this afternoon. Winds will become more southerly overnight, remaining ~10 kt. Outlook: VFR conditions expected through midweek, as high pressure remains in control. South/southwest winds each afternoon may gust to 15-20 kt each day through Wednesday. The next chance of rain and possible degraded flight conditions isn't expected until late Wednesday or Thursday. && .MARINE... As of 315 PM EDT Monday... Key Messages: - Mainly Sub-SCA conditions are expected across the local waters through at least mid-week with primarily southerly winds. - A front moves through late week, bringing the next chance at SCA conditions. This afternoon, expansive high pressure remains centered near Bermuda and extends across the Southeast. Winds are generally out of the S to SW, averaging 10 to 15 knots. Seas are running around 2 to 3 feet and waves in the Chesapeake Bay 1 to 2 feet. Through mid- week, high pressure will remain parked across the western Atlantic in a typical summertime Bermuda High configuration. Winds remain primarily SSW around 10 to 15 kt outside of the daily mid to late- afternoon nearshore seabreeze. The afternoon breeze will likely bring additional localized gusts of 15-20 kt to the lower Chesapeake Bay and nearshore ocean waters each afternoon before winds veer back offshore and diminish through the overnight. These surges will be relatively brief and likely will not require any SCAs. Expect generally benign marine conditions to prevail through at least midweek. The next cold front looks to cross the waters Wednesday night into Thursday morning with increasing NE winds late week. At this time, in-house wind probs still suggest that even behind the front, only brief SCA conditions are possible and conditions may stay under SCA criteria into the weekend. Whether or not the aforementioned front actually moves through or stalls across the area will play an important role in the wind regime late week into the weekend. There is a moderate rip current risk for the northern beaches (including Ocean City, MD) on Tuesday, with a low risk elsewhere. The moderate rip current risk likely continues for the northern beaches into Wednesday. .CLIMATE... As of 145 AM Monday... Record High Temps for 5/18 - 5/20 Record Record Record High/Year High/Year High/Year Location 5/18 5/19 5/20 -------- ---- ----- ------ Richmond 95 (1962) 97 (1962) 97 (2022) Norfolk 95 (1877) 96 (1880) 98 (1996) Salisbury 96 (1911) 97 (2011) 98 (1911) Eliz. City 93 (1987) 95 (1996) 98 (1996) Record High Min Temps for 5/18- 5/20 Record Record Record High High High Min T/Year Min T/Year Min T/Year Location 5/18 5/19 5/20 -------- ---- ----- ------ Richmond 72 (2015) 71 (1997) 71 (2018) Norfolk 75 (1995) 72 (2017) 73 (1996) Salisbury 71 (1953) 70 (1929) 70 (2018) Eliz. City 73 (1995) 72 (2018) 73 (2018) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ DISCUSSION...KMC/MAM AVIATION...KMC/MAM MARINE...AJB/NB CLIMATE...MAM  556 FXUS64 KLUB 181920 AFDLUB Area Forecast Discussion National Weather Service Lubbock TX 220 PM CDT Mon May 18 2026 ...New KEY MESSAGES, SHORT TERM, LONG TERM, FIRE WEATHER... .KEY MESSAGES... Updated at 220 PM CDT Mon May 18 2026 - Extremely critical fire weather conditions are expected through 10 PM CDT tonight, with the potential for dangerous growth and spread of wildfires that will move at a life-threatening pace should ignition occur. - Isolated-to-scattered severe thunderstorms are forecast across the eastern Rolling Plains this afternoon and evening. - Additional storm chances arrive in the Rolling Plains early Tuesday morning along a cold front, with area-wide storm chances, some severe, continuing through the end of the week. && .SHORT TERM... (This afternoon through Tuesday) Issued at 220 PM CDT Mon May 18 2026 A bimodal risk of dangerous fire weather conditions and severe thunderstorms is expected, with the potential for severe storms confined to the eastern Rolling Plains. In the mid/upper-levels, an amplified, negatively-tilting shortwave trough was digging into the Four Corners region, with a 250 mb and 500 mb jet streak approaching 100 kt and 50 kt, respectively, rounding its base as the trough begins to eject northeastward into the central Great Plains. The most substantial large-scale forcing for ascent remains displaced to the north of the CWA as a result of the position of this compacted, shortwave trough, with only modest ascent expected over the Rolling Plains this afternoon. The 12Z RAOB from WFO AMA observed 55 kt and 50 kt of flow at 250 mb and 500 mb, respectively; as the left-exit region of the southern-stream jetlet remained positioned over the TX PH. High-level flow is expected to weaken by this evening as the negatively-tilted trough ejects over the NE Sandhills by 19/00Z, with mid-level flow eventually veering west-southwestward as the CWA becomes positioned beneath the bifurcated jetlets aloft. Deep- and cloud-layer shear will become modest tonight, with broadly cyclonic flow aloft expected to be maintained through the short-term period. At the surface, a quasi-stationary front was located to the north of the CWA and across the OK PH, with the front bending northwestward where a lee cyclone near RTN was present. A weaker surface cyclone was located north of WWD, with the quasi-stationary front bending farther northeast into central KS. Sharp baroclinity exists with this front, with very cool temperatures on its north side along the I-70 corridor in northwestern KS where temperatures are currently in the middle 40s. There is also a 20-degree temperature gradient between LBL and HHF, or about 85 statute miles. The dryline extends southward from near DUX and is currently positioned along the edge of the Caprock Escarpment where a subtle bulge is present, with the 65 degree isodrosotherm delineated along the 100th meridian. Strong, southwesterly winds were present behind the dryline, with a 53 mph gust observed by the WTM site near Shallowater; and winds remain backed towards the south across the moist sector. Intense heating was also underway across the CWA, and temperatures have already breached 95 degrees for some locales in the Rolling Plains as of 1745Z where surface-based cu continues to bubble. Highs will breach 100 degrees east of the Caprock this afternoon, with near-record highs possible at CDS. For details involving the fire weather forecast today, please read the Fire Weather section below. Isolated-to-widely-scattered thunderstorms are forecast to develop along the southern edge of the dryline bulge this afternoon across the eastern Rolling Plains, with the best potential for storms being in the southeastern zones. Storms that develop will be severe. The 12Z RAOB from WFO AMA sampled a well-defined EML, characterized by MLCAPE values near 2,200 J/kg and near 3,200 J/kg for most-unstable parcel trajectories. Mid-level cooling associated with the geopotential height falls have maintained very steep lapse rates atop moderate CINH, with L57 of 8.5 deg C/km, which matches current RAP estimates over the Rolling Plains. MLCINH was half of its value from yesterday, or around -131 J/kg, which will continue to erode across the moist sector throughout the afternoon as hot surface temperatures breach 100 degrees. Low-level convergence will be enhanced by the present of the subtle dryline bulge, and with minimal MLCINH by late-afternoon, rapid thunderstorm development is forecast to occur, with storms quickly becoming severe and posing a risk for damaging wind gusts up to 70 mph and very large hail up to baseball size. The potential for severe-caliber storms will be early on in the convective stage while cloud-layer shear magnitudes remain modest, at or around 30 kt, as the weakening 250 mb flow will curb hydrometeor venting within updrafts. Initial high-based LCLs within the hotter air will also enhance the magnitude of outflow(s), which may result in some localized merging/clustering of cells as diabatic stabilization of the boundary-layer begins. Therefore, the risk for severe storms will be short-lived, but the steep lapse rates and favorable wind profiles for mid-level mesocyclones yields confidence in an isolated, significant hail up to baseball size across the east and southeastern Rolling Plains. Storm chances along the dryline will end after dark, or by 19/03Z. After dark, the quasi-stationary front currently draped across the OK PH will progress southward into the early morning hours Tuesday as the negatively-tilted trough dampens entirely. The movement of the cold front will be convectively-reinforced by a squall line/MCS across western OK and into the TX Big Country. Moist, isentropic ascent atop the sharp convergence along the cold front may result in the formation of a broken line of elevated storms along the front as it moves southward across the Rolling Plains during the predawn hours Tuesday. Moderate thermal instability will be maintained above the anafront, with the potential for large hail between 1-2" in diameter should updrafts be able to become organized. Otherwise, a mixed-mode of rain showers and weaker storms will be more common by dawn Tuesday. The front is forecast to clear south of the CWA after sunrise, with brisk, northerly winds expected post-FROPA. Winds will gradually veer throughout the morning and into the afternoon hours, with winds diminishing Tuesday afternoon. As previously mentioned, broadly cyclonic flow will persist aloft, and with the potential for convectively-augmented vorticity lobes to propagate over the Permian Basin and into the TX Big Country, elevated storms will be possible across the southeastern Rolling Plains into early Tuesday afternoon, but confidence in this scenario is low, and it appears that any storm potential will be south of the CWA. The surface and low-level airmass in the Rolling Plains will have been contaminated by the passage of the synoptic cold front and remnant outflow boundaries, but with upslope, low-level winds beneath southwesterly flow aloft, the potential cannot be ruled out for a localized severe storms across the southeastern zones. Otherwise, much cooler temperatures are forecast area-wide, with highs ranging from the middle 70s across the far southern TX PH to the middle 80s in the southern South and Rolling Plains. Sincavage && .LONG TERM... (Tuesday night through next Sunday) Issued at 220 PM CDT Mon May 18 2026 Broadly cyclonic flow is forecast to persist across the western U.S. through the latter half of the week. Cool temperatures are expected across the CWA Wednesday, with highs struggling to climb above the middle 70s as the post-frontal, upslope flow remains intact. The stalled front is forecast to bend northwestward into eastern NM late Wednesday, and with the CWA positioned beneath the right-entrance region to an amplified jet streak arcing into the Upper Midwest, there is an increasing potential for multiple rounds of storms from Wednesday afternoon into Thursday morning. Global and now-in-range mesoscale NWP guidance has been consistent in the potential for an overnight convective event as a vorticity lobe rotates towards the northeast out of northern Mexico, with the possibility for bands or clusters of storms to progress over W TX. Severe-caliber storms will be possible, with the potential for storms to produce heavy rain, but where exactly storms occur remains unclear. The primary severe hazards involved with storms Wednesday will be large hail, as the stalled front will be south and west of the CWA, thereby keeping parcel trajectories elevated above the cool, stable airmass. Storm chances remain forecast throughout the end of the week and into this weekend as broad troughing persists over the western U.S. Sincavage && .AVIATION... (18Z TAFS) Issued at 1210 PM CDT Mon May 18 2026 Breezy southwest winds sustained near 25-30 kts and gusting to 40 kts will continue at all sites through this evening. Winds will diminish overnight, before increasing out of the north Tuesday morning. VFR will continue. && .FIRE WEATHER... Issued at 220 PM CDT Mon May 18 2026 A high-end fire weather episode is underway today, with extremely critical fire weather conditions expected for a large portion of the CWA. Strong, southwesterly winds between 25-35 mph, with gusts up to 55 mph, will occur across the Caprock and into the far southeastern Texas Panhandle. The only change from the previous forecast(s) was a slight increase in wind gusts, with wind gusts up to 55 mph now expected across most of the Caprock. RH will fall to as low as 4 percent this afternoon amidst hot surface temperatures ranging from the lower-middle 90s on the Caprock to near or in excess of 100 degrees in the Rolling Plains. Very deep mixing of the airmass remains expected, which will facilitate the strongest wind gust potential beyond 3 PM CDT as temperatures peak. The dryline will move into the Rolling Plains by the mid-afternoon hours, with winds transitioning towards the south ahead of it. Isolated-to-scattered severe thunderstorms are forecast across the eastern Rolling Plains this afternoon and evening. Cloud-to-ground lightning strikes may occur in rain-free areas. Storms will be capable of producing damaging wind gusts up to 70 mph, with sudden and erratic changes in wind direction expected near storms. Otherwise, conditions will be favorable for dangerous growth and spread of wildfires through tonight. The Red Flag Warning remains in effect until 10 PM CDT for the Caprock and most of the Rolling Plains. A strong cold front will move through the forecast area during the early morning hours Tuesday, and is currently forecast to cross into the far southern TX PH by 3 AM CDT. Trends in the frontal timing will continue to be monitored. A wind shift to the north will occur immediately post-frontal passage, with wind speeds between 15-25 mph and localized gusts between 30-35 mph expected as the cold front moves through the forecast area. Storms may also develop across the Rolling Plains along the cold front. The front is forecast to clear south of the CWA shortly after sunrise Tuesday, with northerly winds gradually diminishing while veering eastward into the afternoon. && .LUB WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 10 PM CDT this evening for TXZ021>037- 039>043.Wind Advisory until 8 PM CDT this evening for TXZ021>031-033>036. && $$ SHORT TERM...09 LONG TERM....09 AVIATION...19 FIRE WEATHER...09  669 FXUS61 KBGM 181923 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 323 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... Confidence in thunderstorm formation for today and tomorrow has decreased as forecasted conditions are trending toward lower severe parameters. && .KEY MESSAGES... 1) Strong high pressure will bring very hot and humid conditions today and tomorrow. Isolated thunderstorms are possible today, with a better chance for afternoon storms tomorrow. 2) A cold front will push through the area Wednesday, bringing scattered rain showers and thunderstorms. Much more seasonable temperature return for the rest of the week and into the weekend. 3) Memorial Day Weekend could have active weather with seasonable temperatures. && .DISCUSSION... KEY MESSAGE 1... Our first taste of summer continues today and tomorrow as a strong Bermuda high dominates the region. The positioning of the high puts us in the NW quadrant of the system, allowing for strong SW flow to advect warm, humid air in from the southern US. Temps currently in the upper 80s and should warm into the low 90s for valley locations in the next few hours. Dewpoints are also hovering around 60F, which is the usually the threshold for when it starts to feel sticky outside. This humid airmass will allow for overnight lows to remain quite warm, with mid to upper 60s expected across the region. Tomorrow will once again be hot and sticky as SW flow continues through the day. There may be a little more cloud cover as a trough moves into the Great Lakes region, so temps could be a couple degrees cooler than today, but it will feel about the same with heat indices in the upper 80s to low 90s. A cold front is progged to slowly slide in from the NW starting Tuesday night, which will drop temps below 60s north of the Southern Tier, and keep temps in the mid to upper 60s along and south of the Southern Tier. The increasing heat and humidity usually also implies increasing thunderstorm chances, but that is not the case for this set up. The Bermuda high centered off the Carolina coast has a center 500mb height around 592dm. With this strong high so close to the coast, its influence should dominate any thermodynamic processes that would try and get convection going. Looking at the latest model soundings from high-res hourly CAMs, we see a very large and deep inverted V profile due to dry air in the lower atmosphere, with WAA providing a strong cap in the 700-500mb range. CAMs earlier in the day were showing some storms initiating during the early evening hours along the Lake Plain, but the latest runs have backed off, showing a slight chance for some isolated storms moving into NEPA around midnight and the northern Finger Lakes during the overnight hours. These storms would develop off some leftover energy from a MCS currently over IL/IN/MI moves along the edge of the ridge, but confidence is low that this energy would be able to penetrate the dynamics from the strong ridge and generate storms. On Tuesday, the center of the ridge will drift eastward, opening up our area to better chances for thunderstorms from the late morning into the evening hours. Severe parameters for any storm that develops currently looks to be on the low end, with CAPE under 1000 j/kg during the afternoon, mid-level lapse rates around 5-6C/km and 0-6km bulk shear around 30-40kts. One feature that could help get some storms going, especially along the Lake Plain and into the Mohawk Valley, is energy from a shortwave moving across Ontario dipping into our area. Models are showing chances of stronger shear and lift N of the Southern Tier during the late morning to mid afternoon hours that could help develop some storms that could become severe. The big hindrance seems to be morning cloud cover that lingers into the afternoon, reducing surface heating and mid-level lapse rates, which would limit storm development. KEY MESSAGE 2... A cold front is expected to slowly move through the area from the NW Tuesday night thru Wednesday as the Bermuda high flattens and moves to the SW and a trough moves in from the Great Lakes. Scattered rain showers and thunderstorms are expected to develop along the front, but coverage and amount of rain still remains somewhat uncertain. The last few model runs are showing less and less rainfall amounts as the front runs into the drier air mass that has been under the ridge for the past few days. The front and associated precipitation is expected to clear the area by the late afternoon hours. A temperature gradient is expected to set up over the area on Wednesday as the front moves through, with upper end highs in the mid to upper 80s across the Wyoming Valley, falling all the way down to the upper 60s across the northern Finger Lakes into the Tug Hill region. Colder air will once again will filter into the region for the rest of the week, with highs in the mid 50s to mid 60s and lows in the upper 30s to mid 40s. High pressure will dominate with no rain expected thru Friday. KEY MESSAGE 3... With the Memorial Day weekend in sight, the weather unfortunately might not cooperate for those who would like to spend the weekend outside with sunny skies and summer like temperatures. The ridge over our area through the end of the week will slide to the ENE as a trough is currently progged to move into the central portion of the country. The trough looks to eject a shortwave or two into our area Sat and Sun, but the ridge may be strong enough to keep rain out of the area. The positioning of the ridge will keep the cooler airmass in place, with low 60s on Sat and mid to upper 60s on Sunday. Memorial Day could see temps push into the 70s, but depending on how the ridge behaves through the weekend, we could see showers and storms develop. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... Mainly VFR conditions are expected through the 18Z TAF period. There is a slight chance of a shower or thunderstorm tonight, mainly after midnight, for ITH, SYR and RME as an upper level shortwave passes by just to the north and west, but confidence is too low to include in the TAF at this time. Isolated to scattered showers and thunderstorms are expected to develop tomorrow, possibly as early as 16-18Z, which can result in some brief restrictions as the afternoon goes on. West-southwesterly winds with gusts generally around 15 to 20 knots continue through the remainder of the afternoon before becoming light and a bit variable tonight. Southwesterly winds increase again later tomorrow morning and into the afternoon with gusts of 15 to 25 knots expected. Outlook: Tuesday afternoon into Tuesday night...Mainly VFR, but isolated to scattered showers and thunderstorms may result in brief restrictions. Wednesday...Scattered showers and thunderstorms and associated restrictions possible as a frontal boundary moves through the area. Thursday and Friday...Mainly VFR. Saturday...Periods of rain and embedded thunderstorms likely along with associated restrictions. && .CLIMATE... Record highs for our 3 climate sites will be challenged today and Tuesday. Below are the current records and what is forecast. KBGM - 87 degrees, set in 1962 (forecast 88) KSYR - 90 degrees, set in 1962 (forecast 92) KAVP - 93 degrees, set in 1962 (forecast 92) Tuesday... KBGM - 87 degrees, reached in 1962 and 1996 (forecast 88) KSYR - 92 degrees, set in 1971 (forecast 91) KAVP - 92 degrees, set in 1962 (forecast 92) && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...Air Quality Alert until11 PM EDT this evening for NYZ062. && $$ DISCUSSION...JTC AVIATION...DK CLIMATE...JTC  681 FXUS63 KILX 181923 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 223 PM CDT Mon May 18 2026 .KEY MESSAGES... - Repeating rounds of showers and storms could cause flash flooding south of a Shelbyville to Paris line through this evening. A Flood Watch is in effect for these areas. - Additional thunderstorms will develop along an advancing cold front on Tuesday, with a slight risk (level 2 of 5) for severe storms east of Interstate 55. Damaging winds, large hail, and heavy rainfall would be the most likely hazards. && .DISCUSSION... Issued at 223 PM CDT Mon May 18 2026 A line of showers and thunderstorms has stalled out south of the I- 72 corridor this afternoon. Although wind shear has increased over this area since this morning, instability has significantly waned and has prevented storms from largely becoming organized. Despite this, cannot completely rule out a strong updraft or two over the next few hours in far southeast Illinois where RAP mesoanalysis shows SBCAPE of 1000+ J/kg. If any strong storms do occur, damaging winds would be possible. The main threat through the evening will be heavy rainfall with PWATS up around 1.5 to 2 inches and hourly rainfall rates up around 1 inch in the heaviest of storms. A Flood Watch has been issued for areas south of a Shelbyville to Paris line through this evening. Further west, additional thunderstorms have developed over the central Plains ahead of a cold front and will track east through tonight, approaching western Illinois sometime after midnight. These storms should weaken as they enter the area due to lack of instability, though they could still produce gusty subsevere winds as they track through the western half of the state. Most of the shower and storm activity should subside by or before daybreak. The cold front will approach the I-55 corridor around midday Tuesday and be the focus for additional storm development by afternoon. However, one limiting factor will be how long cloud cover from the overnight storms lingers, which would ultimately limit our destabilization potential. CAMS suggest destabilization will be most likely in east-central and southeast Illinois by mid to late afternoon in a moderately sheared environment. However, this appears to be highly conditional at this point. If storms do develop, damaging winds, large hail, and heavy rainfall will be the primary concerns. A drier and cooler period shapes up for midweek as high pressure ridging slides through the Upper Midwest. This will be relatively short-lived as upper troughing moves into the central US and shortwave energy sends several rounds of precipitation through Illinois this weekend into early next week. While the severe weather risk appears low through this period, better moisture/instability building by late weekend/early next week will support thunderstorms at times. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1237 PM CDT Mon May 18 2026 Precipitation will continue to slowly spread east along a remnant outflow boundary through the remainder of this afternoon. Although most of the thunderstorm activity should remain south of the airfields, can't completely rule out a low chance for lightning at KSPI and KDEC through about 00Z. After a lull this evening, another wave of storms will approach from the west late tonight into the early morning hours of Tuesday. PROB30 groups remain in place for this potential at all locations. South-southwest winds will be breezy through Tuesday, with gusts between 20-25 kts. && .ILX WATCHES/WARNINGS/ADVISORIES... Flood Watch until 10 PM CDT this evening for ILZ054>057- 061>063-066>068-071>073. && $$ KEY MESSAGES...NMA DISCUSSION...NMA AVIATION...NMA  703 FXUS65 KBOU 181924 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 124 PM MDT Mon May 18 2026 .KEY MESSAGES... - Rain and mountain/foothill snow will gradually decrease through this evening. A few wet snowflakes may still mix in for the I-25 Corridor. - Near freezing temperatures and frost/freeze highlights for most of the plains, but some uncertainty as to how cold with more lingering cloud cover. - Still unsettled Tuesday through Thursday with scattered to numerous showers and a few storms, most numerous in/near the Front Range. - Warming and drying trend for the weekend. && .DISCUSSION /Through Monday/... Issued at 123 PM MDT Mon May 18 2026 Satellite shows the upper level trough ejecting east/northeast across the forecast area this afternoon, with an enhanced band of precipitation and even a couple thunderstorms moving east across the forecast area. The precipitation will weaken as it moves onto the eastern plains as the upper level trough continues to shear and weaken, and upper level support is replaced by weak subsidence. After the trough passage, we still have some weak upslope to work with so we'll delay the dissipation of showers in/near the Front Range overnight. In fact, a few light showers could linger well past midnight, with the last of them dissipating in/near the southern foothills toward daybreak Tuesday. All existing Winter Storm Warnings and Advisories will remain in tact through 9 pm, but any travel impacts should be waning as precipitation rates decrease. Still can't rule out a few snowflakes mixing in with the snow down toward the I-25 Urban Corridor during heaviest convective showers this afternoon and then this evening as temperatures aloft cool slightly. With regard to the potential freeze across the plains tonight. The latest trends are for more clouds and higher low level moisture, making it more difficult for temperatures to drop. We think most of the Denver/Boulder metro area will stay just above freezing due to mostly cloudy skies persisting through the night, while the plains north and east of Denver could see areas of frost with partial clearing but still some light northerly winds. The Palmer Divide should still end up colder so went with a Freeze Warning there, but even then only the higher elevations above 6500 feet would be most prone to sub freezing temperatures. On Tuesday, the airmass will be more stable but there's still enough moisture and shallow instability for late day shower/isolated storm development in/near the higher terrain. That shower development and coverage will also be supported by weak QG forcing. Temperatures will remain well below normal, with highs only in the 50s over most of the plains. Wednesday should see an uptick in convective shower/storm coverage in the afternoon as lapse rates aloft become moist adiabatic, and we continue to see weak forcing as the mean upper level trough axis holds off to our west. Temperatures will only moderate a few degrees, and still be 10-15 degrees below normal. The trend for Thursday has been toward more active and stronger convective development. The main reason behind this is a stronger and deeper upper level trough dropping southeast across the Rockies. That will support steeper lapse rates, and combined with moderate low level moisture means increasing instability. MLCAPE from various more reliable progs indicate 500-1000 J/kg across most of the plains and I-25 Corridor, so there will be potential for a couple severe storms. As long as this trough passes by Thursday night (and the slower passage has continued in the latest ensemble means), Friday should finally trend drier. Temperatures will then start a warming trend for this weekend with more zonal flow advertised in the ensembles, soeventually we should return to near or above normal temperatures. && .AVIATION /18Z TAFS through 18Z Tuesday/... Issued at 1159 AM MDT Mon May 18 2026 Model cross sections indicate that the ceiling should be at or below BKN-OVC015 at DIA the rest of the today and all of tonight. Will leave a PROB30 in for TSRA this afternoon for 3 or 4 hours based on the instability available. Visiblities should range from 1SM-5SM, lower with the better rain showers through around 00Z this afternoon. Will get visibilities to P6SM after that. There could be patchy fog developing after 06Z tonight, but there is enough uncertainty at this time so I will it out for now. && .BOU WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 9 PM MDT this evening for COZ030- 031-034-035. Frost Advisory from midnight tonight to 8 AM MDT Tuesday for COZ038-042>051. Freeze Warning from midnight tonight to 8 AM MDT Tuesday for COZ041. && $$ DISCUSSION...20 AVIATION...66  783 FXUS61 KGYX 181926 AFDGYX Area Forecast Discussion National Weather Service Gray ME 326 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... A Heat Advisory has been issued for portions of far southern New Hampshire Tuesday. Temperatures will climb into the lower 90s into the early afternoon, with heat index values up to 95. A Marginal Risk for severe thunderstorms has been expanded to include all of New Hampshire and much of southwestern Maine Tuesday. && .KEY MESSAGES... 1. Hot, well above normal temperatures move into the region for Tuesday and Wednesday. Widespread highs in the upper 80s to lower 90s are expected Tuesday, with warm overnight lows in the upper 60s to around 70. Another round of hot temperatures is possible Wednesday, mainly focused from the interior to the coast. 2. An approaching cold front will bring chances for thunderstorms Tuesday and chances for showers and storms Wednesday when the front crosses. Any thunderstorm that develops Tuesday will have the potential to become severe. 3. High pressure builds in Thursday and Friday for mostly dry and cooler weather. Uncertainty exists going into the weekend as moisture approaches from the southwest while high pressure may keep things dry through Saturday. && .DISCUSSION... KEY MESSAGE 1 DESCRIPTION... Broad warm sector across the eastern CONUS is evident on 850mb analysis. Upper jet remains well north of the Great Lakes, and low level SW winds will begin to advect warmer low level temperatures tonight. Brief high pres moves overhead tonight bringing mostly clear skies and calm winds. The incoming low level warm airmass makes its presence known, developing a very steep low level inversion through the evening hours. This is especially pronounced along the ME coast where surface winds become onshore with some fog potentially moving inland late tonight. By Tuesday morning, clear skies should allow full sun for rapid surface heating through the morning hours. The incoming airmass will near record max climo for temps at 850mb over much of New England, sitting in the 99.5 percentile for southern NH and through coastal/interior ME. Daytime mixing will easily tap into this air pushing surface temperatures into the upper 80s, with low 90s for the southern half of NH. This won't be as humid as our summer heat events as the low level moisture is thin. However being the first hot, summer-like heat of the season, went ahead with a Heat Advisory for Hillsborough and interior Rockingham counties in New Hampshire. Heat index values will largely remain in the lower 90s here, but will approach 95 through the afternoon. Southwest breeze continues into the Tues overnight hours, and this will keep temps warm. Lows only dip into the upper 60s to around 70 for much of the interior and coast Tuesday night, mitigating temp recovery. This sets up another warm day for Wednesday, but current forecast highs fall short of those on Tuesday. The hot temps will be more focused on coastal/interior ME and SE NH as a cold front approaches from the west. This should bring more seasonable temps for the mountains and foothills depending on convective activity. As the front pushes off the coast Wed evening, a more refreshing night is expected with lows in the upper 30s to mid 40s. KEY MESSAGE 2 DESCRIPTION... Low pressure and attendant warm front will be lifting northeastward through Quebec Tuesday with the trailing cold front draped southwestward through the Great Lakes region. This will leave northern New England within the warm sector Tuesday into Tuesday night as the cold front is progged to cross Wednesday. Temperatures climbing into the upper 80s to low 90s with dew points around 60 will yield SB CAPE upwards of 1500 J/kg Tuesday afternoon. Deep layer shear of 25 to 35 kts will support some organized convection while a limiting factor will be that the main source of lift, the cold front, will remain well west of the area through Tuesday night. The 12Z HREF suggests that widely scattered storms will remain possible in the absence of lift with few containing robust rotating updrafts. The best storm chances will be during the afternoon across the interior while a few cam solutions suggest storms could track all the way to the coast. The primary hazard will be damaging winds as model soundings show inverted V profiles with dew point depressions greater than 20 degrees. Mid level lapse rates are not impressive while hail will still be possible with any strong rotating updraft. CAMs suggest the chances for storms will diminish Tuesday night, however, as the forecast area remains in the warm sector some overnight convection cannot be ruled out. The cold front will finally arrive into western New England Wednesday morning and will push offshore Wednesday afternoon. Available CAM guidance suggests that a corridor of SB CAPE around 1000 J/kg will develop ahead of the front with deep layer shear around 35 kts. Most solutions push the front through the area prior to peak heating limiting thunderstorm potential to areas south of the mountains. Dry air arriving aloft may also limit any sustained updrafts with the latest outlook from SPC keeping the Marginal Risk south of the area for Wednesday. KEY MESSAGE 3 DESCRIPTION... High pressure builds in from the WNW Wednesday night into Thursday bringing a period of breezy northwest winds. Skies look to be mostly sunny Thursday withs highs ranging from the 50s north to mid 60s along the coast. High pressure will center over southern New England Friday allowing winds to relax across the south while a short wave moving through eastern Canada will maintain breezy conditions across the mountains and central Maine. Highs on Friday will range from the upper 50s north to upper 60s south of the mountains under mostly fair skies. Short waves ejecting out of a trough out of the central US will send moisture towards New England. Global models suggest that high pressure over the Northeast will help suppress this moisture into Saturday into Sunday. The NBM generally keeps PoPs less than 50 percent through the weekend which seems reasonable at this time range. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... Through 18z Tuesday...VFR through this evening as winds become calm. Onshore flow along the ME coast could develop low stratus and/or fog to RKD/PWM at or after midnight local. This may only be in vicinity of PSM. Fog should then lift Tues morning after sunrise and a offshore wind shift for PWM south. 35kt LLWS possible for a duration tonight as a steep surface inversion develops. SW winds increase after sunrise Tuesday, with gusts 15 to 20 kt. Isolated to scattered showers develop into early afternoon, with TS possible through to the evening. TS may be focused along a line, passing west to east. MVFR vis possible in SHRA. Outlook: Tuesday night: VFR as SHRA chances exit the coast in the evening, with SW breeze continuing overnight. No sig wx. Wednesday: Scattered showers and TS may bring localized restrictions late morning early afternoon. Otherwise mainly VFR. Wednesday night: VFR with NW winds gusting up to 20 kts. Thursday through Friday: Mainly VFR. Friday night through Saturday: Clouds may increase and lower across southern NH and Coastal Maine. Low confidence in height and extent, but could see periods of MVFR south of the mountains. && .MARINE... Onshore winds advect moisture over the coastal waters tonight, with areas of fog possible. This may continue into Tues morning. Showers and storms develop inland Tues afternoon and may track towards the NH/ME coast by evening. SW windscontinue overnight, nearing 25 kt but confidence isn't high enough to issue a SCA at this time. Southwest winds turn westerly Wednesday as a cold front approaches and crosses the waters during the afternoon. Winds may gust up to 25 kts with seas approaching 5 feet. Winds and seas are forecast to remain below SCA thresholds Thursday into Saturday as high pressure builds over the Northeast. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...Heat Advisory from 11 AM to 8 PM EDT Tuesday for NHZ012-013- 015. MARINE...None. && $$ DISCUSSION...Cornwell/Schroeter  890 FXUS66 KSGX 181929 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 1229 PM PDT Mon May 18 2026 .SYNOPSIS... Night and morning low clouds and fog will be present each day through the forecast period along the coast for the first half of the week and into portions of the valleys towards the end of the week. High temperatures will be below average in the deserts today and tomorrow, with highs 5 to 10 degrees above average west of the mountains for the first half of the week. Minor fluctuations in temperatures for Thursday through next weekend. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Weak offshore flow through Wednesday will keep low clouds out of the inland valleys but won't be strong enough to keep coastal areas clear of low clouds overnight and in the mornings. It should help with more efficient clearing in the afternoons through Wednesday. A noticeable warming expected today compared to yesterday with the inland valleys expected to be 8 to 15 degrees warmer. An additional 3 to 7 degrees of warming is expected on Tuesday from the coast to the deserts, with continued warming inland Wednesday. The marine layer is expected to deepen Wednesday night into Thursday, which will push low clouds and fog into the inland valleys. A deeper marine layer is expected to be maintained through the weekend. There will be slight day-to-day differences in high temperatures for Thursday through next weekend with high temperatures a few to around 5 degrees above average. && .AVIATION... 181800Z...Coast/Valleys...Low clouds have cleared most areas in OC and the Inland Empire, with low clouds with bases 2500- 4000ft MSL clinging to inland and coastal San Diego county for another hour or two. Low clouds may return this evening (30-50%) to coastal areas with the highest chances in coastal San Diego between 13-17Z. if low clouds do develop, bases would be AOA 1500ft MSL. Mountains/Deserts...Northerly winds will bring gusts 25-35 knots through and below mountain passes through 20-22Z. Pockets of LLWS and downdrafts in lee (south and west) of mountains will be possible. && .MARINE... No hazardous marine conditions are expected through Saturday. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ PUBLIC...CO AVIATION/MARINE...Villafane  946 FXUS63 KFGF 181930 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 230 PM CDT Mon May 18 2026 .KEY MESSAGES... - Another round of showers is expected this afternoon through tonight, bringing an additional few hundredths to two tenths of an inch across mainly southeastern North Dakota into western Minnesota. - Overnight temperatures could drop into the low to mid 30s west of the Red River Valley tonight, and a frost advisory is in effect. Temperatures drop again to near freezing across all of eastern North Dakota and western Minnesota tomorrow night. && .DISCUSSION... Issued at 230 PM CDT Mon May 18 2026 ...Synopsis... Large upper trough continues over the Rockies, with a lead shortwave starting to move through the southwest flow into SD. This shortwave is already bringing some light rain showers starting to move in around the Valley City area. The northern portion of the main upper trough will move into the Plains tonight and then off into Ontario tomorrow, with southern vorticity lobe still down near UT and NV. The northern shortwave moving through should help push high pressure down into the region Tuesday into Tuesday night. Winds return quickly back to the south on Wednesday under southwesterly flow aloft. The split trough remains over the western CONUS Thursday, but starts to move out into the Plains Friday into Saturday. A lot of variation in the ensemble members into how exactly the trough comes out and if there is another shortwave Sunday. Blended solution of some precipitation chances and temperatures rising above seasonal averages by Sunday and Monday continues to seem reasonable. ...Rain chances tonight... CAMs and global models in pretty good agreement on showers currently over the James River Valley spreading northeastward through the rest of the afternoon and into tonight. The bulk of the rain will be exiting out of our eastern counties between midnight and 6 AM, although there will be some lingering light showers/drizzle for a while after. All but portions of the Devils Lake Basin have high probability of seeing at least 0.01 of rain, and there is a 50 to 80 percent probability of at least 0.10 inches mainly in southeastern ND into western MN. ...Temperatures into the 30s tonight... Continued cold air advection pushes 850mb and even 925mb temps in some areas down below 0 C tonight. While skies will remain cloudy and there will be at least a little bit of mixing from northwesterly winds, temperatures look quite cold by tomorrow morning. NBM has probabilities 80 percent and higher for temperatures to get below 36 degrees, and even the less bullish HREF has 40 to 50 percent. With the clouds and wind do not think we will get down as low as the base NBM had us, so tweaked lows up a bit. We should stay above 32, but even with not much actual frost occurring the 33 to 36 degree range west of the Red River Valley could cause some issues to sensitive plants. Went ahead and matched neighbors for a frost advisory tonight. It does look to clear out and go light for winds tomorrow night, so better chances for freeze and frost look likely Wednesday morning. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1234 PM CDT Mon May 18 2026 IFR to MVFR conditions at most spots this afternoon, and there will be not much recovery as more clouds and rain move in from the southwest. Have most airports down to IFR tonight into tomorrow morning, then some recovery to MVFR by the end of the period. Kept rain light and 3-5SM at the lowest. North to northwest Winds that are gusting above 20 kts in some places will drop off just a bit overnight, but then pick up again by mid-day tomorrow. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...Frost Advisory from 1 AM to 9 AM CDT Tuesday for NDZ006-007- 014-015-024-026-028-029-038-049-052-054. MN...None. && $$ DISCUSSION...JR AVIATION...JR  103 FXUS63 KMQT 181932 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 332 PM EDT Mon May 18 2026 .KEY MESSAGES... - Isolated showers and possibly a thunderstorm late this afternoon. - Another round of showers and thunderstorms is expected tonight. Some of the storms could be severe, mainly over the southern half of the U.P. Heavy rainfall is also possible. - Cooler than normal temperatures Tuesday through the rest of the work week. && .DISCUSSION... Issued at 331 PM EDT Mon May 18 2026 The primary focus of the forecast is on the next 24 hours as a dynamic low pressure system lifts through the region. Quiet and benign weather follows for most of the remainder of the week. Latest GOES water vapor imagery place a deep trough over the Rockies and Plains which is moving east. An embedded shortwave over CO is emerging where a sfc low is organizing. These two features lift to northwest WI by tonight, supported by a right entrance region of the upper level jet and strong LLJ, bringing another round of showers and storms to Upper MI for tonight. Afternoon visible satellite imagery has shown a brief window of clearing passing over the western UP allowing for temps to warm into the 60s to mid 70s interior west. Cooler temps are noted near Lake Superior in the mid 40s to mid 50s where a lake breeze is moving onshore. Where transient showers lingered this morning in the east and cloud cover has been stubborn, temps are in the mid 50s to mid 60s. Not much further warming is anticipated given the brief window of clearing, lake breeze influences, and stationary boundary pressing in from the west. Latest SPC meso-analysis indicates some surface instability developing, which is anticipated to increase up to ~1250 J/kg by this evening per 12Z HREF mean as Tds rise into the upper 50s to low 60s. While marginal instability builds this afternoon, some isolated showers and storms are possible (20-40% chance). That said, ~30 kts of shear and little forcing will leave convection short lived and weak. The LLJ moving in tonight significantly increases shear after sunset while instability begins diminishing. With cold front convection well to the south, decreasing SBCAPE/low level lapse rates, and a cap strengthening, it's no surprise the UP (and most of WI) has been completely removed from the SPC tornado outlook. MUCAPE and mid level lapse rates approaching 7 C/km linger into tonight, providing a low chance for strong to severe storms with large hail and damaging winds. The downward trend is also reflected in the latest SPC hail/wind outlooks, downgrading the northern tier of the UP to just general thunderstorms with a marginal risk (~5%) over the south. PWATs ~1.5 inch with the main wave tonight will yield rainfall totals of a few hundreths to around 0.5 inches, highest amounts over the west where there is a 25-50% chance for amounts up to 1 inch. This is captured by the WPC marginal risk of excessive rainfall (~5% chance of exceeding Flash Flood Guidance). Otherwise temps fall into the 40s and 50s tonight, coldest northwest. Isolated to scattered showers linger into Tuesday, however instability will likely be elevated and only briefly uncapped in the east/south-central for a few hours at best. Thunder is in the forecast, but strong to severe storms are not expected. Highs in the east half on Tuesday will be in the upper 50s to upper 60s, lower in the northwestern UP where mid 40s to mid 50s are expected. From there, the low departs to the northeast and high pressure over the Plains replaces it. This maintains over the Great Lakes through most of the work week yielding dry weather until the weekend. Lingering troughing aloft keeps colder northwest flow through Wednesday, resulting in temps between 5-15 degrees below normal; highs in the 40s and 50s and lows in the 30s. A warming pattern is then expected toward next weekend as mid level ridging slowly builds over the southeast and extends up into the Great Lakes. Another trough over the Rockies on Friday looks to move toward the Upper Great Lakes during the weekend, bringing back precip to the UP. Instability with this is lacking, so impactful strong to severe storms are not anticipated. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 152 PM EDT Mon May 18 2026 Visible satellite reveals partial clearing taking place over the western half of Upper Michigan as of 18z Mon, with surface observations showing a corresponding upward trend in flight categories at area terminals. Expect an eventual trend back down to low end MVFR or IFR roughly 21-00z this evening at KIWD and KSAW as the next round of showers moves into the region. Probabilities for strong to severe thunderstorms have decreased into tonight, but will still carry TSRA at KIWD and PROB30s at KCMX and KSAW through ~10z Tue. Will see gradual improvement from west to east as the system exits Tue morning, but cigs will likely hold at MVFR if not IFR until after 18z Tue. && .MARINE... Issued at 331 PM EDT Mon May 18 2026 A low pressure moving northeast over Upper Michigan and Lake Superior tonight into Tuesday. This tightens the pressure gradient and increases northeast winds over the west and north-central portions of the lake to 20-30 kts tonight. As the low moves overhead, winds become northwest and strongest winds shift from the west half to the east as colder air moves in. Probabilities of gales to 35 kts are 25% or less, highest in the east Tuesday afternoon. Showers and storms are expected with this system into Tuesday morning, however severe storms are no longer expected. This rainfall will prolong fog over the east into Tuesday morning. High pressure returns winds to 20 kts or less by Wednesday afternoon, winds likely maintain light into the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Dense Fog Advisory until 11 AM EDT Tuesday for LSZ244-264>266. Dense Fog Advisory from 1 AM to 8 AM EDT Tuesday for LSZ245>247. Dense Fog Advisory from 8 PM this evening to 8 AM EDT Tuesday for LSZ248>251. Dense Fog Advisory until 2 PM EDT Tuesday for LSZ267. Lake Michigan... None. && $$ DISCUSSION...77 AVIATION...CB MARINE...77  314 FXUS61 KBGM 181936 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 336 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... Confidence in thunderstorm formation for today and tomorrow has decreased as forecasted conditions are trending toward lower severe parameters. && .KEY MESSAGES... 1) Strong high pressure will bring very hot and humid conditions today and tomorrow. Isolated thunderstorms are possible today, with a better chance for afternoon storms tomorrow. 2) A cold front will push through the area Wednesday, bringing scattered rain showers and thunderstorms. Much more seasonable temperature return for the rest of the week and into the weekend. 3) Memorial Day Weekend could have active weather with seasonable temperatures. && .DISCUSSION... KEY MESSAGE 1... Our first taste of summer continues today and tomorrow as a strong Bermuda high dominates the region. The positioning of the high puts us in the NW quadrant of the system, allowing for strong SW flow to advect warm, humid air in from the southern US. Temps currently in the upper 80s and should warm into the low 90s for valley locations in the next few hours. Dewpoints are also hovering around 60F, which is the usually the threshold for when it starts to feel sticky outside. This humid airmass will allow for overnight lows to remain quite warm, with mid to upper 60s expected across the region. Tomorrow will once again be hot and sticky as SW flow continues through the day. There may be a little more cloud cover as a trough moves into the Great Lakes region, so temps could be a couple degrees cooler than today, but it will feel about the same with heat indices in the upper 80s to low 90s. A cold front is progged to slowly slide in from the NW starting Tuesday night, which will drop temps below 60s north of the Southern Tier, and keep temps in the mid to upper 60s along and south of the Southern Tier. The increasing heat and humidity usually also implies increasing thunderstorm chances, but that is not the case for this set up. The Bermuda high centered off the Carolina coast has a center 500mb height around 592dm. With this strong high so close to the coast, its influence should dominate any thermodynamic processes that would try and get convection going. Looking at the latest model soundings from high-res hourly CAMs, we see a very large and deep inverted V profile due to dry air in the lower atmosphere, with WAA providing a strong cap in the 700-500mb range. CAMs earlier in the day were showing some storms initiating during the early evening hours along the Lake Plain, but the latest runs have backed off, showing a slight chance for some isolated storms moving into NEPA around midnight and the northern Finger Lakes during the overnight hours. These storms would develop off some leftover energy from a MCS currently over IL/IN/MI moves along the edge of the ridge, but confidence is low that this energy would be able to penetrate the dynamics from the strong ridge and generate storms. On Tuesday, the center of the ridge will drift eastward, opening up our area to better chances for thunderstorms from the late morning into the evening hours. Severe parameters for any storm that develops currently looks to be on the low end, with CAPE under 1000 j/kg during the afternoon, mid-level lapse rates around 5-6C/km and 0-6km bulk shear around 30-40kts. One feature that could help get some storms going, especially along the Lake Plain and into the Mohawk Valley, is energy from a shortwave moving across Ontario dipping into our area. Models are showing chances of stronger shear and lift N of the Southern Tier during the late morning to mid afternoon hours that could help develop some storms that could become severe. The big hindrance seems to be morningcloud cover that lingers into the afternoon, reducing surface heating and mid-level lapse rates, which would limit storm development. If the clouds are not as widespread as currently forecast or we can see some clearing by late morning, thunderstorm coverage and severe chances will definitely increase. KEY MESSAGE 2... A cold front is expected to slowly move through the area from the NW Tuesday night thru Wednesday as the Bermuda high flattens and moves to the SW and a trough moves in from the Great Lakes. Scattered rain showers and thunderstorms are expected to develop along the front, but coverage and amount of rain still remains somewhat uncertain. The last few model runs are showing less and less rainfall amounts as the front runs into the drier air mass that has been under the ridge for the past few days. The front and associated precipitation is expected to clear the area by the late afternoon hours. A temperature gradient is expected to set up over the area on Wednesday as the front moves through, with upper end highs in the mid to upper 80s across the Wyoming Valley, falling all the way down to the upper 60s across the northern Finger Lakes into the Tug Hill region. Colder air will once again will filter into the region for the rest of the week, with highs in the mid 50s to mid 60s and lows in the upper 30s to mid 40s. High pressure will dominate with no rain expected thru Friday. KEY MESSAGE 3... With the Memorial Day weekend in sight, the weather unfortunately might not cooperate for those who would like to spend the weekend outside with sunny skies and summer like temperatures. The ridge over our area through the end of the week will slide to the ENE as a trough is currently progged to move into the central portion of the country. The trough looks to eject a shortwave or two into our area Sat and Sun, but the ridge may be strong enough to keep rain out of the area. The positioning of the ridge will keep the cooler airmass in place, with low 60s on Sat and mid to upper 60s on Sunday. Memorial Day could see temps push into the 70s, but depending on how the ridge behaves through the weekend, we could see showers and storms develop. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... Mainly VFR conditions are expected through the 18Z TAF period. There is a slight chance of a shower or thunderstorm tonight, mainly after midnight, for ITH, SYR and RME as an upper level shortwave passes by just to the north and west, but confidence is too low to include in the TAF at this time. Isolated to scattered showers and thunderstorms are expected to develop tomorrow, possibly as early as 16-18Z, which can result in some brief restrictions as the afternoon goes on. West-southwesterly winds with gusts generally around 15 to 20 knots continue through the remainder of the afternoon before becoming light and a bit variable tonight. Southwesterly winds increase again later tomorrow morning and into the afternoon with gusts of 15 to 25 knots expected. Outlook: Tuesday afternoon into Tuesday night...Mainly VFR, but isolated to scattered showers and thunderstorms may result in brief restrictions. Wednesday...Scattered showers and thunderstorms and associated restrictions possible as a frontal boundary moves through the area. Thursday and Friday...Mainly VFR. Saturday...Periods of rain and embedded thunderstorms likely along with associated restrictions. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...Air Quality Alert until 11 PM EDT this evening for NYZ062. && $$ DISCUSSION...JTC AVIATION...DK  352 FXUS61 KBOX 181937 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 337 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... Heat Advisories issued for most of Southern New England Tuesday and Wednesday with the first multi-day stretch of hot temperatures and a moderate degree of humidity. Record high temperatures remain possible. && .KEY MESSAGES... - First multi-day stretch of hot temperatures (in the mid to upper 90s away from the South Coast) with a moderate degree of humidity Tuesday and Wednesday. Near record heat possible. - Isolated thunderstorms possible Tuesday north and west of Interstate 95. Better chances for strong to severe thunderstorms on Wednesday with strong straight line winds the main risk. - Seasonable and dry Thursday and Friday. - Cooler and unsettled weather is possible Memorial Day Weekend, but confidence remains low. && .DISCUSSION... KEY MESSAGE 1...First multi-day stretch of hot temperatures (in the mid to upper 90s away from the South Coast) with a moderate degree of humidity Tuesday and Wednesday. Near record heat possible. A spell of anomalous heat (e.g. 850 mb temps running in the upper teens Celsius, which are 2-3 standard deviations above climatological normals for late May) will build into Southern New England on Tue, only slightly cooler on Wed. SW breezes should also mitigate the risk for cooling seabreezes but will keep the immediate South Coast, Cape and Islands considerably cooler than further inland (highs mid 70s/low 80s). Away from the South Coast, highs on Tuesday should reach the mid 90s in most areas with upper 90s possible due to westerly downsloping in the CT and Merrimack Valleys. With a southward-sagging frontal boundary nearby on Wed, highs project to be a few degrees cooler in the upper 80s/low 90s north of the Mass Pike and low-mid 90s in the CT-RI-SE MA corridor, with still cooler temps 70s/near 80 South Coast/Cape and Islands. Even though the NAM-based guidance shows dewpoints in the mid 60s to low 70s, it usually demonstrates a moist-bias in these strong-mixing days and values should be closer to the mid 50s to mid 60s Tue and Wed. That's also a factor which will be alluded to in the next Key Message to follow. We're looking at a spell of hot temperatures but a generally drier heat, not necessarily oppressively humid like we typically see with forecasted temperatures this hot. With dewpoints mid 50s to lower 60s, it's more of "drier" heat and the difference between the air temperature and the apparent temperature (heat index) may not be that much different. Framing this setup a little more, if this type of setting were deeper in the summer months, it might not rise to the level of heat headlines. However NWS HeatRisk graphics outline portions of the CT and Merrimack Valleys in the Major HeatRisk classification. Given this datapoint, forecasted heat indices which are borderline (mid to upper 90s), and that there may be individuals who are not yet accustomed to this degree of heat as of yet, we opted to issue a Heat Advisory for Tuesday and Wednesday. KEY MESSAGE 2...Isolated thunderstorms possible Tuesday north and west of Interstate 95. Better chances for strong to severe thunderstorms on Wednesday with strong straight line winds the main risk. The warm airmass Tuesday and Wednesday will create a maginally to moderately-unstable convective setting, with some risk for thunderstorms both days. I'm skeptical of the NAM's inflated instability parameters given the above moist-bias (upper 60s to low 70s) and the highest CAPE values stem from the NAM and its downscaled 3-km version, but even the drier GFS shows about 1000 J/kg on Tuesday and again on Wednesday. Soundings show a well-mixed PBL favorable for downdraft and gust-front production if any showers or storms can pop up. What may trigger storms on Tuesday is debatable, as the best mid- level winds/stronger wind shear and strong cold front is to our north and west. A passing sfc trough could be enough to generate isolated storms north and west of I-95; one or two could become strong if storms develop with strong winds the main risk; the lack of sufficiently strong wind shear would lead to more pulse- type storms. Wednesday may offer a better chance at strong to severe storms with the approaching cold front interacting with moderate instability. The front's timing is in some question but somewhat better chances for thunderstorms near to south of the Mass Pike. Both days feature a Level 1 of 5 (Marginal Risk) for severe weather. KEY MESSAGE 3...Seasonable and dry Thursday and Friday. Thursday and Friday are fairly straightforward, with a 1030mb high pressure system across the Great Lakes on Thursday before shifting east on Friday, leading to dry weather. What is most noticeable is the cooler air mass. 850mb temperatures lower to +2C to +5C on Thursday, a far cry from the +18C to +20C observed just a few days prior. With a dry and well-mixed boundary layer, mixing up to 850mb seems likely, tapping into those cooler temperatures aloft and yielding highs in the middle 60s to around 70F both days. Considering climatological normal maximum temperatures for mid-May are generally in the upper 60s to lower 70s, this is more typical for the time of year versus the early taste of summer that challenged daily record highs. With clear skies Thursday night and nearly calm winds as surface high pressure moves overhead, good radiational cooling is expected, allowing temperatures to lower into the 40s, with perhaps some upper 30s across the higher elevations of northern and western Massachusetts. While slightly cooler than normal, temperatures will be nowhere near record-setting. KEY MESSAGE 4...Cooler and unsettled weather is possible Memorial Day Weekend, but confidence remains low. The unofficial start to summer this weekend brings the potential for unsettled weather, though there remains a good deal of uncertainty due to model variability at this range. However, it bears watching given the numerous outdoor activities planned for Memorial Day Weekend. Global deterministic and ensemble guidance show the potential for rainfall, particularly Saturday night into Sunday, though there remain large differences in timing among models and runs. That said, it is worth noting both the AIGFS and ECMWF AIFS depict a 1035mb surface high pressure system situated east of New England, suppressing precipitation to the west. This solution would favor a drier, albeit cooler, weekend with easterly flow and highs generally in the lower 60s. For now, the NBM PoPs remain the best first estimate for the upcoming weekend, but do not write it off just yet, there is still pounds of time for forecast adjustments. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 18Z TAF Update: Mainly VFR conditions through Wed. However, stratus and fog will likely develop over the ocean as SW flow brings higher dewpoints over cooler ocean and this may impact portions of the south coast and Cape/Islands tonight. LLWS risk for all terminals tonight heading into early Tue morning. Isolated t-storms possible Tue afternoon, but uncertain on if they will impact any terminals. E-NE wind becoming S 10-20 kt this afternoon. S-SW wind 5-10 kt tonight increasing Tue with gusts to 25 kt developing. KBOS...High confidence in TAF. Seabreeze today with wind shift to S late today or early evening. KBDL...High confidence in TAF.Outlook /Tuesday Night through Saturday/... Wednesday: VFR. Breezy. Chance SHRA, slight chance TSRA. Wednesday Night: VFR. Breezy. Thursday through Friday: VFR. Friday Night: VFR. Chance SHRA. Saturday: Mainly VFR, with local IFR possible. SHRA likely. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through Tuesday Night: High confidence. Issued small craft advisories valid from 12z Tuesday through Wednesday evening. SW winds will be increasing to around 15-25 kt Tuesday and remain so through Wednesday, higher over the southern waters. Seas will also be building to around 4-6 ft, with some 7 footers possible Tuesday night over the southern waters. Mainly dry weather prevails through Tuesday night, although fog may develop both tonight and Tuesday night. Outlook /Tuesday Night through Saturday/... Wednesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Chance of rain showers, isolated thunderstorms. Wednesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. Thursday: Winds less than 25 kt. Seas locally approaching 5 ft. Thursday Night through Friday: Winds less than 25 kt. Friday Night: Winds less than 25 kt. Chance of rain showers. Saturday: Winds less than 25 kt. Rain showers likely. && .CLIMATE... Record Highs for Tue May 19... BOS 90/1949 BDL 94/1962 PVD 91/2017 ORH 92/1962 Record Highs for Wed May 20... BOS 91/1996 BDL 99/1996 PVD 95/1996 ORH 91/1903 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Air Quality Alert until 11 PM EDT this evening for CTZ002. Heat Advisory from 11 AM Tuesday to 8 PM EDT Wednesday for CTZ002>004. Air Quality Alert from 11 AM to 11 PM EDT Tuesday for CTZ003- 004. MA...Air Quality Alert until 11 PM EDT this evening for MAZ008>011. Heat Advisory from 11 AM Tuesday to 8 PM EDT Wednesday for MAZ003>007-010>019-026. RI...Heat Advisory from 11 AM Tuesday to 8 PM EDT Wednesday for RIZ001>004. Air Quality Alert from 11 AM to 11 PM EDT Tuesday for RIZ001>008. MARINE...Small Craft Advisory from 11 AM Tuesday to 8 PM EDT Wednesday for ANZ254>256. && $$ DISCUSSION...Loconto/Dooley AVIATION...Dooley/McMinn MARINE...Loconto/Dooley CLIMATE...KJC  336 FXUS63 KABR 181937 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 237 PM CDT Mon May 18 2026 .KEY MESSAGES... - Rain showers (embedded thundershowers) into the evening hours. Most areas less than a half inch. No severe storms expected. - Frost possible (33 to 36 degrees) across portions of central SD early Tuesday morning. Much better potential for widespread frost/freeze conditions Wednesday morning. Temperatures forecast around 29-33 degrees. && .DISCUSSION... Issued at 237 PM CDT Mon May 18 2026 Starting to see an uptick in areal coverage of showers (embedded thundershowers) as activity continues moving north-northeast across the region. Instability is lacking today, so don't expect anything in the way of severe storms. Did some massaging of PoPs through late afternoon into early evening to account for radar trends and expectations. Total rainfall amounts forecast to remain less than a half inch for most areas. Later tonight into early Tuesday morning, surface high pressure settles in across the western Dakotas. Chilly temperatures in the 30s are forecast across the CWA tonight, and there are some concerns about frost potential with temps dropping to between 33 and 36 degrees. Clouds are expected much of the night, along with a northwest breeze, so certainly not ideal radiational cooling conditions. In fact, inherited NBM lows seemed a tad too cool, so blended in some warmer (ConsMOS) readings to bring readings up a couple degrees in spots. All said and done, forecast lows across central SD are generally between 33 and 36 degrees, so have therefore issued a Frost Advisory for the western CWA. Much better potential for more widespread frost/freeze conditions late Tuesday night into Wednesday morning as the surface high is more overhead. Winds are expected to be lighter, with mostly clear skies (especially for eastern areas) leading to better radiational cooling conditions. Current forecast lows are closer to 30-32 degrees for many areas. Highly likely more headlines are in store. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1236 PM CDT Mon May 18 2026 Terminals KABR,KATY,KPIR,KMBG Areas of -SHRA will move northeast into and through the region this afternoon and evening. VSBY may drop to MVFR in precipitation. CIGs will generally be MVFR, although forecast is for IFR at times in areas of precipitation and overall lower cloud cover potential during the evening hours. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...Frost Advisory from 4 AM CDT /3 AM MDT/ to 9 AM CDT /8 AM MDT/ Tuesday for SDZ003>005-009-010-015-016-033>035-045. MN...None. && $$ DISCUSSION...TMT AVIATION...TMT  322 FXUS63 KDTX 181937 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 337 PM EDT Mon May 18 2026 .KEY MESSAGES... - Warm and humid conditions exist today and Tuesday which support the risk of severe thunderstorms each day, mainly during the afternoon and evening hours. The strongest storms are capable of damaging wind, large hail, and isolated tornadoes. - A cold front Tuesday night ushers in dry and cooler weather for Wednesday and Thursday. - The next chance of rain arrives Friday and Friday night. && .DISCUSSION... Severe Thunderstorm Watch 221 is in effect until 800 pm for the mature MCS inbound into SE Mi. Damaging wind gusts of 70 mph or greater have been reported and remain the primary hazard as the line tracks across SE Mi. Instability trends remain on track as full morning to early afternoon sun lifted temperatures to near 90 all areas. Model MLCAPE up around 2000 J/kg in HREF mean and RAP projections of hourly mesoanalysis add confidence to persistence. The system is already demonstrating benefits of the locally enhanced wind shear profile supplied by the parent MCV resulting in a mature linear convective mode now expected to maintain organization while crossing SE Mi. Storms exit eastward into Ontario by 00Z at or before watch expiration. Another round of severe thunderstorm potential for Tuesday is set up by Midwest low pressure as it moves into upper Michigan while pulling a cold front through the central Great Lakes. SE Mi remains firmly in the warm sector of this system throughout the day with early to mid evening cold front timing offering time for instability to become sufficient. Morning clouds and a stray shower likely slow the pace of surface heating compared to today, however model projections of MLCAPE place 2000 J/kg in reach by 21Z Tuesday afternoon, especially toward the Ohio border. This occurs in a very similar wind profile compared to today in terms of moderate unidirectional shear except with a deeper 40-45 knot layer through 500 mb. Storm initiation timing is the primary uncertainty as shown in the wide range of hi-res model solutions that collectively suggest a later afternoon consensus. Later timing equates to less impact to SE Mi in terms of coverage area and also a more isolated severe threat before storms can better organize while the cold front moves through the area. Frontal passage Tuesday night, before midnight, sweeps storms out of SE Mi and sweeps in cooler air for the mid week period. A broad area of surface high pressure and short wave ridging ensures below normal temperatures but dry weather during this time period as well. Central Plains to Ohio valley low pressure then brings the next round of showers into Lower Mi later Friday and Friday night. && .MARINE... Attention to the near-term forecast will focus on the ongoing line of thunderstorms that extend across central Michigan. This line will pass across the eastern Great Lakes this evening and will bring heavy downpours, frequent lightning, and strong to severe weather. Strong to severe thunderstorms will be capable of producing wind gusts aoa 50 knots for all of the open water locations. Hail to an inch and/or a waterspout cannot be ruled out but are secondary hazards for severe weather. Prior to this line of thunderstorm arriving, isolated to scattered thunderstorm activity will be possible. A Severe Thunderstorm Watch is in effect until 8 PM EDT. Outside of any thunderstorm activity, breezy southwest to south flow will persist, bringing non-thunderstorm gusts on the order of 20 to 25 knots. The main line of storms will exit late tonight but isolated to scattered showers and thunderstorms will be possible overnight. Renewed strong to severe thunderstorm chances will again be possible tomorrow afternoon and evening which will bring additional chances to see all storm hazards included wind gusts aoa 50 knots. These stronger storms will be most favorable from central Lake Huron and locations south. Outside of thunderstorms, gusts to 25 knots will again be possible during daylight hours. Re-issuance of Small Craft Advisories will be likely. && .PREV DISCUSSION... Issued at 158 PM EDT Mon May 18 2026 AVIATION... Conditions deteriorate this afternoon and evening as a line of strong to severe thunderstorms moves through the airspace. VFR ceilings and visibilities drop sharply along the interface of the convective line with temporary IFR conditions likely. Upstream observations and local storm reports indicate gusts in excess of 70 mph are possible with this organized line. Current trajectories reveal storm motion of approximately 45 mph, forecast to move through the terminals between 20Z and 23Z. A conditionally unstable airmass is allowing for a few pre-trough storms to develop ahead of the line with low confidence that these storms survive across the airfields. However, did move up the TEMPO period for the Metro terminals to account for the possibility of slightly earlier discrete activity. Limited model signal for widespread redevelopment late this evening behind the line, although better chances exist at MBS. Winds decrease slightly overnight, holding from the southwest into Tuesday with a mainly dry start and D21/DTW Convection...Most likely time-frame for thunder will be from 20-22Z. A period of IFR visibility will accompany the line of storms. Potential for additional thunderstorms has decreased for Tuesday afternoon/evening, but a chance remains. DTW THRESHOLD PROBABILITIES... * High for thunderstorms this afternoon and early evening, then low- medium for thunderstorms Tuesday afternoon/evening. * Medium for ceilings at or below 5000 ft with thunderstorms this afternoon and evening. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ421-422- 441>443. Lake St Clair...Small Craft Advisory until 10 PM EDT this evening for LCZ460. Michigan waters of Lake Erie...None. && $$ DISCUSSION...BT MARINE.......BT AVIATION.....KGK You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.  304 FXUS64 KHUN 181936 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 236 PM CDT Mon May 18 2026 ...New NEAR TERM... .KEY MESSAGES... Updated at 1030 AM CDT Mon May 18 2026 - Low chances (10%-20%) for showers across northeast Alabama today. - Low to medium chances (20-60%) for showers and thunderstorms returning late Tuesday, then medium to high chances (50-90%) for showers and thunderstorms each day, from Wednesday through the weekend && .NEAR TERM... (Tonight) Issued at 236 PM CDT Mon May 18 2026 A warm and breezy day is ongoing across the Tennessee Valley with afternoon temperatures in the mid to upper 80s and winds gusting to 20 mph out of the south. A fair weather Cu field has developed across most of the CWA, but no showers have been detected on radar. Latest CAMs indicate a very low chance (5-10%) of a shower or isolated thunderstorm in NE AL, but most locations are expected to remain dry through tonight. With the warm and moist airmass in place, overnight temperatures only drop down into the mid to upper 60s. Winds should remain around 5mph keeping fog from developing early tomorrow morning. && .SHORT TERM... (Tuesday through Thursday) Issued at 1030 AM CDT Mon May 18 2026 Mid-level ridge which has been in place to our east for several days will begin to weaken over the local area on Tuesday as a trough swings across the northern Plains and associated sfc low transitions northeastward across the Great Lakes region. The sfc cold front will push eastward throughout the day Tuesday approaching the local area late on Tuesday into Wednesday. It will slow and become near stationary over MS/AL/GA on Wednesday. As a result, chances for rain/storms will increase Tuesday night into Wednesday along and ahead of the frontal boundary with continued rounds of activity on Wednesday and Thursday as a series of shortwaves transition along the western edge of the subtropical ridge over the TN Valley as plenty of moisture remains in place along the stalled frontal boundary. Morning CAMs coming in are backing off significantly in precip chances with the initial precip coming in tomorrow night with the cold front. Any notable precip chance remain west of I-65 until after sunrise on Wednesday but that still may be too high if trends continue. Rain chances will peak Wednesday and Thursday during the daytime hours between 70%-90% both days. Shear profiles aren't impressive at this time and the severe threat remains low but will feel very summer like in terms of convection with sufficient instability, moisture, and lift in place to fuel these rounds of activity. We are included in a "Marginal" risk for Excessive Rainfall by WPC for Wednesday and Thursday but any rainfall will be beneficial at this point and QPF totals are not anticipated to result in any sort of impactful flooding outside of ponding on roadways where localized higher amounts are seen. High temps will remain above normal on Tuesday before moderating mid- week into the low/mid 80s under increased cloud cover and weakening ridge. && .LONG TERM... (Thursday night through Sunday) Issued at 1045 PM CDT Sun May 17 2026 This pattern will continue largely unabated from Thursday night into the weekend, with a broad summer-like subtropical ridge centered near Bermuda and deep SWRLY flow persisting across the TN Valley. A series of shortwaves are expected to ride along the trough/ridge interface across the region and bring bouts of increased shower/storm activity. Timing this is difficult, as the distinct nature of these shortwaves is difficult to discern in the model guidance. Nevertheless, increased instability during the daytime will certainly act to regulate chances for showers/storms during the period. Thermo profiles during the Thurs-Friday period do not appear to change significantly, with generally moist- adiabatic type profiles in the increasing deep/humid airmass. PWs climbing to near 1.7 inches and only modest CAPEs and weak-modest shear would suggest the largest threat may be due to any localized flash flooding that could result, especially with the prospect for slow-moving training storms. Shear may increase a little into the weekend, but still would characterize as modest at best. Overall, this is reminiscent of a warm, early summer pattern with highs mostly in the 80s and warm nights with lows in the 60s. && .AVIATION... (18Z TAFS) Issued at 1134 AM CDT Mon May 18 2026 VFR conditions are forecast to continue through the TAF period. Gusty southerly winds up to 20-25 knots can be expected this afternoon before subsiding around sunset tonight. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...GH SHORT TERM....KG LONG TERM....KDW AVIATION...GH  295 FXUS65 KMSO 181936 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 136 PM MDT Mon May 18 2026 .DISCUSSION... KEY MESSAGES: - Showers with a few thunderstorms(20-50% chance) today through Wednesday, especially across northwest Montana and over the Continental Divide. - Frost/freeze concerns remain for Tuesday morning. - Mountain snow above 6000 feet with raw/cold backcountry conditions later Wednesday into Thursday morning over the Divide, Glacier National Park, extending west towards the Idaho border. - Return to summer-like conditions as moderating temperatures are expected late week into next weekend. Temperatures this morning were quite cold across the region. Whenever you get such a cold trough originating from the northern latitudes like Alaska, you almost have to expect possible frosty mornings. The Ravalli County Airport located northeast of Hamilton saw a low of 21 degrees! Looking back at climatology, its really not that uncommon to get these types of systems in May where highs struggle to get out of the 30s and 40s. Looking at the climatology for the Hamilton area for the second half of May the coldest low temperature recorded was 24 degrees set on May 22, 2010. The Stevensville COOP recorded a 15 degrees on May 30, 2001. Even other locations, like the higher 3000 feet valleys in Idaho were in the upper 20s this morning. With the chance for frost continuing into Tuesday morning, we issued more frost advisories. We listed the percentile ranges of low temperatures for select locations in the "additional details" section to help people make decisions on if they need to cover things or not. For those who are unaware, we typically will not issue frost/freeze advisories for the high valleys(i.e. southwest Montana/Divide) that will continue to have sub- freezing nights for the remainder of May until the climatological last frost/freeze day. If we get a cold system thereafter, we may choose to issues advisories then. For the next two days, we'll be under cyclonic flow with disturbances dropping out of southern British Columbia. There is generally a 20 to 50 percent chance for lightning over the mountains of northwest Montana this afternoon and evening. Other impacts from the showers will be gusty winds to 35 mph in the stronger cells. Then shortwave energy from the Gulf of Alaska will carve a larger upper level trough which digs over Montana later Wednesday into Thursday. With the colder temperatures aloft, this will drive the snow levels down to around 6000 feet. This could bring additional snowfall to the mountains over the Divide, including Glacier National Park. Also the associated cold front will shift south and west with time just after peak heating which will allow for possible showers and thunderstorms. The latest probabilities show the best instability present across northwest Montana. This system will basically move off into the Northern Plains by Thursday into Friday while we will have rising heights (moderating temperatures). A general ridge will build by next weekend and temperatures will rise back into the 70s and 80s across the region. There is a hint that a trough may either bring mild and windy conditions on Sunday, or dig across the region by early next week. && .AVIATION...Scattered showers and thunderstorms will be possible today across the region. The more intense cells will be found across northwest Montana, especially initiated over the mountains. They will have a general storm motion from northwest to southeast around 23 knots. Main impacts will be isolated lightning, brief visibility reduction and gusty winds to 30 knots. A few lingering showers are possible tonight across northwest Montana thanks to a shortwave dropping out of British Columbia. There could be patchy fog along river bottoms elsewhere Tuesday morning. Another round of showers with a few thunderstorms are expected Tuesday afternoon and evening with the focus over the Divide and points west. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Frost Advisory from midnight tonight to 9 AM MDT Tuesday for Bitterroot/Sapphire Mountains...Flathead/Mission Valleys... Lower Clark Fork Region...Missoula/Bitterroot Valleys. ID...Frost Advisory from midnight MDT /11 PM PDT/ tonight to 9 AM MDT /8 AM PDT/ Tuesday for Eastern Lemhi County...Northern Clearwater Mountains...Southern Clearwater Mountains. Frost Advisory from 11 PM this evening to 9 AM PDT Tuesday for Orofino/Grangeville Region. && $$  268 FXUS65 KVEF 181935 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 1235 PM PDT Mon May 18 2026 .KEY MESSAGES... * Winds will continue to diminish through the afternoon, and widespread wind impacts are not expected the rest of the week. * Temperatures will warm up through the week as a dry weather pattern sets up over the region. && .DISCUSSION...Through this Weekend. The system that brought strong winds to the region last night pulls away from the area today. With the trough axis currently centered over northeast Utah, the area remained under cool, dry northerly flow through the morning. Winds are not nearly as strong at last night, but gust 25-35 MPH were reported in many locations through the morning hours. The strongest winds today have been in the Colorado River Valley, though even there the north winds have been on a downward trend in the past few hours after the strongest gusts topped out around 40 MPH this morning. Winds will continue to diminish through the rest of the afternoon and by 4 PM, gusts will be 25 MPH or less in for most of the region. With the strongest winds and highest risk for wind impacts behind us, let the High Wind Warning in the Colorado River Valley expire. Isolated gusts to 40 MPH are possible here through the early afternoon which could cause impacts on the lakes, otherwise widespread wind impacts are not expected. With no significant systems are expected the rest of the week, so not expecting widespread wind impacts through the weekend Breezy afternoons with gusts 20-30 MPH are possible at times, especially tomorrow and Wednesday in the Colorado River Valley as north winds linger a few more days. Today will be much cooler compared to recent conditions as high temperatures this afternoon are expected to run about 10 degrees below normal. Heights will increase through the week as troughing weakens, which will result in dry conditions and a warming trend. Temperatures will warm each day with high temperatures returning to normal by Wednesday. The warming trend then continues into the weekend, with above normal temperatures Thursday onward climbing a few degrees each day the second half of the week. By the weekend, high temperatures will run 5-8 degrees above normal. && .AVIATION...For Harry Reid...For the 18Z Forecast Package...Gusty northeasterly winds (with directional variability between 020-050 true) will continue into this afternoon, with gusts to around 20-25KT expected on at least an intermittent basis. Gusts are expected to diminish by mid-afternoon, with sustained speeds dropping to around 10KT. Winds back to the north late evening and to the northwest overnight, before shifting to the north and northeast again on Tuesday morning. Another round of gusty northeasterly winds is expected mid-morning through early to mid- afternoon Tuesday, though slightly weaker than today, with gusts expected to top out around 20KT. VFR conditions with clear skies will prevail. For the rest of southern Nevada, northwest Arizona and southeast California...For the 18Z Forecast Package...Gusty northerly to northeasterly winds are expected across the area through this afternoon, with gusts to 20-25KT common for most locations outside of the Lower Colorado River Valley. There, from roughly KIFP to KEED, terrain-enhanced northerly winds will gust to around 35KT through late afternoon, slowly decreasing through the evening. Elsewhere, gusts will largely diminish after sunset, with elevated and gusty northerly to northeasterly winds returning across southern Nevada and northwestern Arizona by mid-morning Tuesday. VFR conditions will prevail, with only a FEW high clouds late in the period across far southern areas. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION...Nickerson AVIATION...Phillipson For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter  426 FXUS64 KLUB 181938 CCA AFDLUB Area Forecast Discussion...CORRECTED National Weather Service Lubbock TX 238 PM CDT Mon May 18 2026 ...New KEY MESSAGES, SHORT TERM, LONG TERM, FIRE WEATHER... .KEY MESSAGES... Updated at 220 PM CDT Mon May 18 2026 - Extremely critical fire weather conditions are expected through 10 PM CDT tonight, with the potential for dangerous growth and spread of wildfires that will move at a life-threatening pace should ignition occur. - Isolated-to-scattered severe thunderstorms are forecast across the eastern Rolling Plains this afternoon and evening. - Additional storm chances arrive in the Rolling Plains early Tuesday morning along a cold front, with area-wide storm chances, some severe, continuing through the end of the week. && .SHORT TERM... (This afternoon through Tuesday) Issued at 220 PM CDT Mon May 18 2026 A bimodal risk of dangerous fire weather conditions and severe thunderstorms is expected, with the potential for severe storms confined to the eastern Rolling Plains. In the mid/upper-levels, an amplified, negatively-tilting shortwave trough was digging into the Four Corners region, with a 250 mb and 500 mb jet streak approaching 100 kt and 50 kt, respectively, rounding its base as the trough begins to eject northeastward into the central Great Plains. The most substantial large-scale forcing for ascent remains displaced to the north of the CWA as a result of the position of this compacted, shortwave trough, with only modest ascent expected over the Rolling Plains this afternoon. The 12Z RAOB from WFO AMA observed 55 kt and 50 kt of flow at 250 mb and 500 mb, respectively; as the left-exit region of the southern-stream jetlet remained positioned over the TX PH. High-level flow is expected to weaken by this evening as the negatively-tilted trough ejects over the NE Sandhills by 19/00Z, with mid-level flow eventually veering west-southwestward as the CWA becomes positioned beneath the bifurcated jetlets aloft. Deep- and cloud-layer shear will become modest tonight, with broadly cyclonic flow aloft expected to be maintained through the short-term period. At the surface, a quasi-stationary front was located to the north of the CWA and across the OK PH, with the front bending northwestward where a lee cyclone near RTN was present. A weaker surface cyclone was located north of WWD, with the quasi-stationary front bending farther northeast into central KS. Sharp baroclinity exists with this front, with very cool temperatures on its north side along the I-70 corridor in northwestern KS where temperatures are currently in the middle 40s. There is also a 20-degree temperature gradient between LBL and HHF, or about 85 statute miles. The dryline extends southward from near DUX and is currently positioned along the edge of the Caprock Escarpment where a subtle bulge is present, with the 65 degree isodrosotherm delineated along the 100th meridian. Strong, southwesterly winds were present behind the dryline, with a 53 mph gust observed by the WTM site near Shallowater; and winds remain backed towards the south across the moist sector. Intense heating was also underway across the CWA, and temperatures have already breached 95 degrees for some locales in the Rolling Plains as of 1745Z where surface-based cu continues to bubble. Highs will breach 100 degrees east of the Caprock this afternoon, with near-record highs possible at CDS. For details involving the fire weather forecast today, please read the Fire Weather section below. Isolated-to-widely-scattered thunderstorms are forecast to develop along the southern edge of the dryline bulge this afternoon across the eastern Rolling Plains, with the best potential for storms being in the southeastern zones. Storms that develop will be severe. The 12Z RAOB from WFO AMA sampled a well-defined EML, characterized by MLCAPE values near 2,200 J/kg and near 3,200 J/kg for most-unstable parcel trajectories. Mid-level cooling associated with the geopotential height falls have maintained very steep lapse rates atop moderate CINH, with L57 of 8.5 deg C/km, which matches current RAP estimates over the Rolling Plains. MLCINH was half of its value from yesterday, or around -131 J/kg, which will continue to erode across the moist sector throughout the afternoon as hot surface temperatures breach 100 degrees. Low-level convergence will be enhanced by the present of the subtle dryline bulge, and with minimal MLCINH by late-afternoon, rapid thunderstorm development is forecast to occur, with storms quickly becoming severe and posing a risk for damaging wind gusts up to 70 mph and very large hail up to baseball size. The potential for severe-caliber storms will be early on in the convective stage while cloud-layer shear magnitudes remain modest, at or around 30 kt, as the weakening 250 mb flow will curb hydrometeor venting within updrafts. Initial high-based LCLs within the hotter air will also enhance the magnitude of outflow(s), which may result in some localized merging/clustering of cells as diabatic stabilization of the boundary-layer begins. Therefore, the risk for severe storms will be short-lived, but the steep lapse rates and favorable wind profiles for mid-level mesocyclones yields confidence in an isolated, significant hail up to baseball size across the east and southeastern Rolling Plains. Storm chances along the dryline will end after dark, or by 19/03Z. After dark, the quasi-stationary front currently draped across the OK PH will progress southward into the early morning hours Tuesday as the negatively-tilted trough dampens entirely. The movement of the cold front will be convectively-reinforced by a squall line/MCS across western OK and into the TX Big Country. Moist, isentropic ascent atop the sharp convergence along the cold front may result in the formation of a broken line of elevated storms along the front as it moves southward across the Rolling Plains during the predawn hours Tuesday. Moderate thermal instability will be maintained above the anafront, with the potential for large hail between 1-2" in diameter should updrafts be able to become organized. Otherwise, a mixed-mode of rain showers and weaker storms will be more common by dawn Tuesday. The front is forecast to clear south of the CWA after sunrise, with brisk, northerly winds expected post-FROPA. Winds will gradually veer throughout the morning and into the afternoon hours, with winds diminishing Tuesday afternoon. As previously mentioned, broadly cyclonic flow will persist aloft, and with the potential for convectively-augmented vorticity lobes to propagate over the Permian Basin and into the TX Big Country, elevated storms will be possible across the southeastern Rolling Plains into early Tuesday afternoon, but confidence in this scenario is low, and it appears that any storm potential will be south of the CWA. The surface and low-level airmass in the Rolling Plains will have been contaminated by the passage of the synoptic cold front and remnant outflow boundaries, but with upslope, low-level winds beneath southwesterly flow aloft, the potential cannot be ruled out for a localized severe storm across the southeastern zones. Otherwise, much cooler temperatures are forecast area-wide, with highs ranging from the middle 70s across the far southern TX PH to the middle 80s in the southern South and Rolling Plains. Sincavage && .LONG TERM... (Tuesday night through next Sunday) Issued at 220 PM CDT Mon May 18 2026 Broadly cyclonic flow is forecast to persist across the western U.S. through the latter half of the week. Cool temperatures are expected across the CWA Wednesday, with highs struggling to climb above the middle 70s as the post-frontal, upslope flow remains intact. The stalled front is forecast to bend northwestward into eastern NM late Wednesday, and with the CWA positioned beneath the right-entrance region to an amplified jet streak arcing into the Upper Midwest, there is an increasing potential for multiple rounds of storms from Wednesday afternoon into Thursday morning. Global and now-in-range mesoscale NWP guidance has been consistent in the potential for an overnight convective event as a vorticity lobe rotates towards the northeast out of northern Mexico, with the possibility for bands or clusters of storms to progress over W TX. Severe-caliber storms will be possible, with the potential for storms to produce heavy rain, but where exactly storms occur remains unclear. The primary severe hazards involved with storms Wednesday will be large hail, as the stalled front will be south and west of the CWA, thereby keeping parcel trajectories elevated above the cool, stable airmass. Storm chances remain forecast throughout the end of the week and into this weekend as broad troughing persists over the western U.S. Sincavage && .AVIATION... (18Z TAFS) Issued at 1210 PM CDT Mon May 18 2026 Breezy southwest winds sustained near 25-30 kts and gusting to 40 kts will continue at all sites through this evening. Winds will diminish overnight, before increasing out of the north Tuesday morning. VFR will continue. && .FIRE WEATHER... Issued at 220 PM CDT Mon May 18 2026 A high-end fire weather episode is underway today, with extremely critical fire weather conditions expected for a large portion of the CWA. Strong, southwesterly winds between 25-35 mph, with gusts up to 55 mph, will occur across the Caprock and into the far southeastern Texas Panhandle. The only change from the previous forecast(s) was a slight increase in wind gusts, with wind gusts up to 55 mph now expected across most of the Caprock. RH will fall to as low as 4 percent this afternoon amidst hot surface temperatures ranging from the lower-middle 90s on the Caprock to near or in excess of 100 degrees in the Rolling Plains. Very deep mixing of the airmass remains expected, which will facilitate the strongest wind gust potential beyond 3 PM CDT as temperatures peak. The dryline will move into the Rolling Plains by the mid-afternoon hours, with winds transitioning towards the south ahead of it. Isolated-to-scattered severe thunderstorms are forecast across the eastern Rolling Plains this afternoon and evening. Cloud-to-ground lightning strikes may occur in rain-free areas. Storms will be capable of producing damaging wind gusts up to 70 mph, with sudden and erratic changes in wind direction expected near storms. Otherwise, conditions will be favorable for dangerous growth and spread of wildfires through tonight. The Red Flag Warning remains in effect until 10 PM CDT for the Caprock and most of the Rolling Plains. A strong cold front will move through the forecast area during the early morning hours Tuesday, and is currently forecast to cross into the far southern TX PH by 3 AM CDT. Trends in the frontal timing will continue to be monitored. A wind shift to the north will occur immediately post-frontal passage, with wind speeds between 15-25 mph and localized gusts between 30-35 mph expected as the cold front moves through the forecast area. Storms may also develop across the Rolling Plains along the cold front. The front is forecast to clear south of the CWA shortly after sunrise Tuesday, with northerly winds gradually diminishing while veering eastward into the afternoon. && .LUB WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 10 PM CDT this evening for TXZ021>037- 039>043. Wind Advisory until 8 PM CDT this evening for TXZ021>031-033>036. && $$ SHORT TERM...09 LONG TERM....09 AVIATION...19 FIRE WEATHER...09  751 FXHW60 PHFO 181944 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 944 AM HST Mon May 18 2026 .SYNOPSIS... An unstable and somewhat wet trade wind pattern will continue through mid-week, with brief downpours possible. During the second half of the week, a strengthening area of high pressure north of the islands will increase stability across the region, producing drier, but windier conditions. && .UPDATE... Trade showers continue this morning, with rainfall reports between 1 and 2 inches at higher elevations, but only 0.10 to around 0.40 at lower elevations. Today should end up looking much like yesterday, with additional showers, mainly windward and mauka, through the day. Some of these showers may be heavy due to high PW values, and a few will spill over to (or develop in) leeward areas. All this is handled well by the current forecast and no update is planned at this time. && .PREV DISCUSSION... Issued at 342 AM HST Mon May 18 2026 This morning, local satellite and radar imagery shows just a few light scattered showers moving into the islands on moderate easterly trade wind flow. While some areas of the state received significant rainfall totals yesterday, shower intensity and coverage eased area-wide after sunset. With that said, the early morning sounding from Hilo continues to show over two inches of precipitable water, compared to the much drier Lihue sounding. Broad troughing aloft persists over the islands, and with this amount of ample moisture available, expect that a generally wet trade wind pattern will continue for the next couple of days with frequent showers over windward areas, especially for the Big Island. Some showers could produce brief downpours, similar to those that were observed this past weekend at times. Showers will generally favor windward areas during the overnight and morning hours, with scattered leeward showers developing during the afternoons. Additionally, dewpoints will continue to linger in the upper 60s to low 70s, which should make temperatures feel warmer than normal. Increased stability and stronger trade winds are expected by Thursday. Latest global guidance remains in good agreement with a strong high developing far north of the state during the second half of the week, which should result in windy conditions. Winds could potentially reach Wind Advisory levels Thursday into Friday for select areas downstream of terrain. Drier conditions are also expected during this time, but scattered showers embedded within the windy trade wind flow will continue, especially during the night and early morning hours. && .AVIATION... Moderate to locally breezy trades expected for the next couple days. Low cigs and SHRA should primarily impact windward and mauka locations with some limited spillover to leeward areas. MVFR conds possible in heavier SHRA, otherwise VFR prevails. AIRMET Sierra is in effect for mtn obsc for Kauai, Oahu, Maui and windward sections of the Big Island. Will continue to monitor for possibly adding AIRMET Tango for moderate low level turbulence through the afternoon as tradewind strengthen slightly. && .MARINE... A surface high centered about 1,400 nautical miles northeast of the islands will generate moderate to locally strong trades over the next few days. This anchored high will strengthen and expand during the second half of the week and will cause the trade winds to strengthen to widespread strong speeds with near gales over the windier zones around Maui County and the Big Island. A Small Craft Advisory (SCA) is currently in effect for the windier zones around Maui County and the Big Island. The SCA will expand in area later this week as the trades strengthen. A small size, short to medium period north northwest is expected on Tuesday.Otherwise, another small north northwest bump is possible over the weekend. A series of small long-period south-southwest swells will provide surf near the summer average along south facing shores throughout the week. Strengthening trades later this week will bring an increase of short-period energy and will bring elevated surf along east facing shores by Thursday or Friday. Water levels peaking between 2.5 to 3.0 ft MLLW during today's high tides may result in some minor overwash within low lying coastal areas this afternoon. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 AM HST Wednesday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel. && $$ DISCUSSION...Vaughan AVIATION...Almanza MARINE...Kino  746 FXUS63 KGID 181944 AFDGID Area Forecast Discussion National Weather Service Hastings NE 244 PM CDT Mon May 18 2026 .KEY MESSAGES... - A handful of severe storms capable of producing large hail, damaging wind gusts or an isolated tornado will be possible between 3-8PM today. The severe threat will mainly be for places near and east of HWY-81. - A few showers, areas of drizzle and non-severe thunderstorms will be possible this afternoon across areas outside of the severe threat. - Highs, following the passage of a cold front today, will peak in the 50s and 60s for much of the area. A few north central Kansas locations as well as far southeast Nebraska areas could see highs in the 70s. - The next chance of precipitation will come Wednesday night (40-50% chance). - Highs the rest of the week will stay in the 60s for Tuesday/Wednesday/Thursday, the low to mid 70s for Friday and the upper 70s to low 80s for Saturday. && .DISCUSSION... Issued at 244 PM CDT Mon May 18 2026 A broad upper level trough over the Rockies has been the driving force for severe weather yesterday and today. Water vapor imagery shows an upper level wave crossing much of the Central Plains this afternoon. Severe thunderstorms are currently going up along a boundary stretching from Hebron, NE to Lincoln, KS, as of 2:30 PM CDT. The main threat are a few tornadoes, golf ball size hail, and wind gusts up to 60 mph. Severe weather is forecast for Mitchell and Jewell continues in KS and Thayer county in NE. Storms will move out the region by the late afternoon with a majority of the severe weather threat off to the east. Areas behind the cold front, which is much of the county warning area, will see low stratus lingering into tonight causing light rain and drizzle. Tonight, temperatures are forecast to drop down into the mid to upper 30s across the county warning area. However, cloud cover and elevated winds, around 15 mph, will likely keep frost from forming. Low stratus should start to clear out by the early morning hours west to east. Tomorrow, temperatures are forecast to climb up into the 60s. Low temperatures tomorrow night are forecast to drop down into the lower to mid 30s across the northern half of the warning area. Unlike tonight, winds are forecast to be on the lighter side allowing frost to potentially form. Southwesterly flow aloft will continue across the Central Plains. A shortwave trough is forecast to move through the region Wednesday bringing forth chances for more precipitation. Temperatures will remain on the cooler side through the middle of the week as the cooler airmass lingers across the Plains. Thus, temperatures are forecast to range from the 60s to low 70s through Friday. Daily chances for thunderstorms returns from Wednesday night into the weekend. NSSL machine learning program and the CSU machine learning program are pegging Friday with a low chance of Severe weather mainly across the southern half of the county warning area. It is possible this low chance of severe weather shifts further south. Temperatures will warm this weekend as an upper level ridge begins to build across the Central US. This warm pattern will continue into early next with conditions drying out. The NBM 25th to 75th percentiles have high temperatures ranging from the lower 80s to the mid 90s. Thus, fairly high confidence on above normal temperatures to start out next week. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 101 PM CDT Mon May 18 2026 For KGRI/KEAR Airports: MVFR conditions will continue to across the much of the area this afternoon through tonight. Low stratus could could cause to SHRA and DZ for the next few hours. The low stratus will clear west to east late tonight/early tomorrow morning bringing back VFR conditions by tomorrow afternoon. There is a chance for so TSRA near KGRI this afternoon, but convection will likely stay off to the east. Winds are forecast to remain out of the north through the period. Wind gusts are forecast to diminish tonight, but winds will remain elevated around 14 kts during the overnight hours. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...Johnson AVIATION...Johnson  753 FXUS63 KLOT 181944 AFDLOT Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 244 PM CDT Mon May 18 2026 .KEY MESSAGES... - Another round of showers and thunderstorms on Tuesday, some of which could be strong to severe mainly during the afternoon hours. - Summer-like warmth and breezy winds will prevail through Tuesday, then cooler temperatures and dry conditions will return for the middle of the week. - Milder weather returns heading into the weekend, though with at least intermittent shower/thunderstorm potential. && .DISCUSSION... Issued at 244 PM CDT Mon May 18 2026 Through Tonight... Convection and associated MCV responsible for this morning's severe weather has moved into Lower Michigan. Air mass in the wake of this wave is substantially more stable and combined with modest height rises in its wake should prevent any renewed convective development this afternoon or evening. Severe convection currently developing over the central Plains is likely to congeal into a large QLCS that will move toward the mid-Mississippi Valley tonight. Most intense convection is likely to focus farther southwest across Missouri, likely intercepting the low level jet and orphaning the convection farther north across Iowa. This should result in convection over Iowa diminishing as it moves eastward into northern IL with some guidance suggesting very little shower activity would actually make it into our CWA. Have reflected this trend in pop grids, but opted to maintain at least chance pops given the inherent uncertainties in forecasting convective evolution. Pressure field is recovering in the wake of the morning convection which has allowed winds to pick and become rather gusty from the southwest. Gustiness of the winds will generally tend to abate by sunset, except perhaps remaining somewhat gusty tonight in the urban heat island of Chicago. -Izzi Tuesday... Convectively induced vorticity maximum will slide through northeast Illinois into early Tuesday, well outpacing the cold front, and therefore we may have some showers hanging on into the area, but confidence is medium-high that thunderstorm coverage will be on the lower side. Any lingering MCS cold pool footprint and residual cloudiness will likely delay destabilization into midday Tuesday, though additional storm development appears somewhat probable across the southeast half of the forecast area Tuesday afternoon/evening as the cold front finally pushes through the forecast area. Southwesterly flow ahead of the front will maintain mid to possibly upper 60s dewpoints and support MLCAPE approaching 1500 J/Kg. Stronger mid-level flow on the southeastern periphery of the Model guidance would support some additional vorticity maximum riding along the front, and flow to the southeast of the mid level trough across the northern Great Lakes will likely support enough storm development and some organization for a hail/wind threat during this time. This would be favored along and southeast of I-55, with short term ensemble guidance suggesting the window for much of NE IL and NW IN being fairly limited in the mid to late afternoon. For the Chicago metro area the picture is also a bit muddled for precipitation chances. High res guidance is mostly dry for the area, whereas global guidance and NAM/RAP does bring some shower activity across Chicagoland along the front in the early afternoon. KMD Wednesday onward... Following the cold front, surface high pressure is progged to build east into the western Great Lakes region Wednesday and Thursday. Dry, but breezy and cooler weather is expected both days, with temps mainly in the 60s, but only in the 50s near Lake Michigan with northeast-east flow off the lake. Nighttime lows in the 40s are expected. The high then drifts off to the east Thursday night, with the upper level pattern favoring a series of mid-level disturbances tracking through the area Friday into the weekend. This will support milder temperatures, but also some occasional shower/thunderstorm chances into the holiday weekend. Ratzer && .AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 109 PM CDT Mon May 18 2026 Wind field has been substantially altered by storms this morning, but will revert back to a south-southwest direction early this afternoon. Pressure gradient is baggier in the wake of the storms than originally forecast, so gustiness of the winds may be slower to develop today than indicated in the TAFs. Showers and storms that develop over the central Plains today will move east and likely reach northern Illinois in a quickly decaying state late tonight/early Tuesday morning. Confidence is low in whether this activity will reach the terminals, so opted to just hang onto a PROB30 in the TAFs. Finally, confidence in winds Tuesday is on the lower end of the spectrum. There is a chance wind fields could be altered by diminishing storms, which could play havoc on directions and speeds. However, if wind fields aren't significantly altered, then winds will likely be even stronger than indicated in the TAFs. - Izzi && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at weather.gov/chicago  134 FXUS63 KPAH 181950 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 250 PM CDT Mon May 18 2026 .KEY MESSAGES... - Breezy today with thunderstorms continuing through the afternoon and early evening (40-70% chance), and limited potential for a few strong to severe storms. - High rain chances (70-90%) from Tuesday afternoon into Tuesday night. A few strong to severe storms and locally heavy rain are possible. - Daily rain chances continue through the rest of the week and weekend (Thursday is the driest) with cooler late week highs in the 70s to near 80. && .DISCUSSION... Issued at 250 PM CDT Mon May 18 2026 Training showers and thunderstorms continue to brush against the northern edge of the Quad State, tracking east-northeastward. Separately, scattered showers and thunderstorms have tracked northeastward through the Quad State late morning through the present and should continue the rest of the afternoon to early evening as an impulse from Texas moves through. CAMs continue to vary on development, with the HRRR eager to generate storms from the impulse, while the ARW favors a Missouri MCS early evening. Current radar presentation suggests the Missouri convection tracks near/along I-64 while the impulse tracks near the Ohio River. MLCAPE is up to 1500-2500J/kg while effective bulk shear is 20-30kts. Dew points in the upper 60s to lower 70s are accompanied by PWs of 1.8-2.0in. A marginal risk covers much of the Quad State with a sliver of a slight in the far north, and some strong storms are likely to develop, but severe weather is more limited. A Lake Wind Advisory remains though, of the primary lakes, only Lake Barkley/Kentucky Lake have avoided the off and on showers/storms. Models agree on an overnight MCS in Missouri weakening on approach late tonight with limited PoPs in the west Tuesday morning. Redevelopment on residual boundaries, or a new MCS, are varied across models making timing difficult. One the environment following this afternoon/evening becomes known, it will help shape model assessment of development tomorrow. More commonly in the models at the moment, a band of storms pushes eastward late Tuesday into the evening with an evening/overnight cold frontal passage. PW values remains high, with continued very warm temperatures as highs surge to the upper 80s again. Plenty of CAPE will be available but shear is even more limited than today and will be a limiting factor. A slight risk covers most of the Quad State. When it comes to rainfall, some models produce a max along the Ohio River into SWIN with heavy development and training from the Texas sourced impulse today. Otherwise, models focus on the training showers/storms in the north that have progressed into the I-64 corridor. Heavy rainfall in either of these zones is possible today, but antecedent dry conditions will keep flooding potential limited for today. As for tomorrow, models don't tend to show much of any training but, should any occur over areas which receive decent rainfall today, flooding issues can develop. A cold front moves through Tuesday evening resulting in much colder conditions for the rest of the workweek. Highs drop to the mid 70s to near 80 Wednesday through Friday while midweek lows drop to the 50s. Temperatures trend slowly warmer late week into the weekend. Active weather remains in the forecast as the front stalls near enough to the Quad State Wednesday for some showers and possibly a few storms (mainly in the south). Thursday has the driest ensemble as high pressure moves through the Great Lakes but outliers exist such as the GFS which tracks a small surface low through Western Kentucky. The front is more likely to push back north Friday as better model agreement yields likely- categorical PoPs. The boundary could help with producing some strong to severe storms but confidence is low at this time. Continued upper flow from the southwest will keep rain chances in through the weekend. LREF 7-day rainfall has a 25th-75th percentile spread of 1.5-3 inches, which would help with ongoing drought. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1239 PM CDT Mon May 18 2026 Scattered shower and thunderstorm activity will continue to develop this afternoon and increase in coverage. Heavier banding is located just north of KMVN and will remain through the afternoon while, across the Quad State, showers and storms are moving in from the southwest. Locally heavy rain is possible, and lightning is likely to be a factor several hours in a row for some sites. The Kentucky Pennyrile area has the least potential for thunder. MVFR cigs are possible with storms, as are vsby reductions to MVFR or IFR. A few stronger storms are possible. Breezy winds gusting to 18-25kts today drop to around 8-10kts sustained overnight, then become breezy again tomorrow. Dry weather is forecast later tonight into tomorrow with rain beginning to re-enter the picture in the west at the end of the TAF period. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Lake Wind Advisory until 4 PM CDT this afternoon for ILZ075- 081-085. MO...Lake Wind Advisory until 4 PM CDT this afternoon for MOZ100. IN...None. KY...Lake Wind Advisory until 4 PM CDT this afternoon for KYZ007>009-011-012. && $$ DISCUSSION...ATL AVIATION...ATL  254 FXUS63 KBIS 181952 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 252 PM CDT Mon May 18 2026 .KEY MESSAGES... - Rain showers continue into this evening south central ND into the James River Valley before departing to the east-northeast tonight. Slight chance of showers elsewhere. - Lows tonight into Tuesday morning dip into the upper 20s to lower 30s. Freeze Warnings and Frost Advisories have been issued. Cold temperatures again possible Tuesday night/Wednesday morning, mainly east. - Unsettled weather pattern develops mid to end of the week. Greatest and most widespread chances (about 30 to 60 percent) come Thursday into Friday. && .DISCUSSION... Issued at 223 PM CDT Mon May 18 2026 Current surface analysis places low over the upper midwest with notable frontal boundary stretching to the southwest through the central plains. High remains over southern Saskatchewan into central Montana. Upper level analysis places trough over Saskatchewan southward towards the central Rockies. Southeast flow over our area with some embedded short waves is resulting in broad shower activity over much of South Dakota into southeast/south central North Dakota. For tonight, ongoing showers will continue into this evening before departing to the east/northeast. In the meantime, surface high settles into the area, mainly western locations, with cool air continuing to slide in. This will result in sub freezing temperatures over parts of western and north central North Dakota, therefore a Freeze Warning has been issued. Further east, confidence is a little lower as to how cold it will get given the persistant cloud cover. With that said, lows look to dip close to or reach freezing, so have decided to go with a Frost Advisory for that area even though technically "frost" will not form, but sensitive plants could be damaged, especially if temperatures are a degree or two lower than forecast. Trough pushes east early Tuesday, with a low amplitude ridge passing over for Tuesday into Wednesday. Expect a gradual warm- up for high temperatures, but Tuesday night may see some freezing lows, mainly over our east given the high passing over and clearing skies. Next trough digs in over the western CONUS on Thursday with our flow shifting southwesterly before the system closes off and ejects to the northeast to close out the week. Greatest chances for precipitation come Thursday into Friday (about 30 to 60 percent chance). Warming trend expected going into the weekend with NBM temperature spreads being quite confident in seeing well above average temperatures by late weekend. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1253 PM CDT Mon May 18 2026 Low stratus over the state will continue to bring widespread MVFR with localized IFR ceilings through the rest of today into the overnight hours. Improvement is expected late tonight over far western North Dakota, then over much of western and parts of north central North Dakota Tuesday morning. && .BIS WATCHES/WARNINGS/ADVISORIES... Freeze Warning from 1 AM CDT /midnight MDT/ to 9 AM CDT /8 AM MDT/ Tuesday for NDZ001>005-009-010-012-017>020-022-031>033- 040-041-043-044-055>059. Frost Advisory from 1 AM CDT /midnight MDT/ to 9 AM CDT /8 AM MDT/ Tuesday for NDZ013-023-025-035>037-042-046>048-050-051- 060>062. && $$ DISCUSSION...JJS AVIATION...JJS  493 FXUS63 KEAX 181957 AFDEAX Area Forecast Discussion National Weather Service Kansas City/Pleasant Hill MO 257 PM CDT Mon May 18 2026 .KEY MESSAGES... * Significant threat for severe weather across NW Missouri this evening with destructive hail, damaging winds and tornadoes. This threat will transition to a damaging winds and QLCS tornadoes as scattered storms develop into a line and build southeast. * Substantial flood threat tonight across the region with rainfall rates expected to exceed 2"/hr. Flood watch in effect tonight into Tuesday morning. Additional rainfall amounts of 1.5-3+" with pockets exceeding 5". * Cooler and drier conditions develop on Tuesday and continue into Wednesday. * Rainfall chances return to the region Thursday through the end of the weeekend. && .DISCUSSION... Issued at 253 PM CDT Mon May 18 2026 Mature trailing stratiform MCS worked through the area overnight leading to a widespread 1-2 inches of rain across the region. Saw MCS backbuild across central Missouri through the late morning, keeping temperatures quite cool through mid-day. Have seen signs of gravity waves emanating from the tail end of the the MCS, spreading to the north-northwest. Have started to see some partial-rapid clearing across eastern KS into western Missouri leading to nice warming- roughly west of I-35. Pseudo warm front/outflow boundary is poised just south of the forecast area across central Missouri. This boundary may try to lift north through the late afternoon hours. If that occurs, could see an isolated storms develop south of a line from Butler through Clinton leading to large hail/gusty winds. Expect surface temperatures to continue to warm through the afternoon hours into the upper 70s to 80s, leading to rapidly increasing instability. By late this afternoon, expect moderate to extreme instability with SB CAPE values of 4000-5000 J/kg roughly along and west of the I-35 corridor. Surface low pressure centered near Salina KS is expected to lift northeast this afternoon to southwest Iowa into the evening. Discreet supercells have already begun developing across central into northern KS, building east in time in what is a very volatile environment. 0-6 km shear is in the 40-50 knot range across eastern KS should easily support supercells, with the potential for very large hail and tornadoes. Expect supercells to remain discreet building into Northwest Missouri in the early evening hours, capable of producing very large hail, damaging winds and the potential for strong tornadoes. As the severe weather event evolves, expect the supercells to evolve into a squalline and build southeast in time. Expect severe threat to transition towards damaging winds, but could still see QLCS tornadoes with embedded supercells along the line. Training storms, along with precipitable water values of nearly two inches and deep warm cloud depths will lead to efficient rainfall. CAMs have been fairly consistent with another 1.5-3+" of rainfall across the region tonight, with pockets of 5+". HREF and REFs probabilities for 2"/hr rainfall rates are approaching 50%. Flash flood guidance across the area is low with the recent rains, generally running from 1-2.5"/6 hour period. Collaborated with WPC and surrounding offices to raise excessive rainfall outlook to moderate across most of the area. Cams suggest storms may linger Tuesday morning as the surface boundary moves slowly through the area. Have extended the flood watch through 18Z south of the Missouri River. Much cooler conditions are expected midweek behind the front with high in the 60s and lows in the 40s. A developing trough late week across the Northern Plains could bring additional instability showers and storms to the region as early as Thursday. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1210 PM CDT Mon May 18 2026 Scattered showers and thunderstorms have nearly cleared our forecast area moving into central MO. SSE winds will increase with gusts up to 30 knots by early afternoon, continuing through early evening hours. A line of severe thunderstorms will impact STJ between roughly 00z and 03z tonight, moving through the KC metro terminals likely between 02z and 05z tonight. Severe wind gusts will be possible along the leading edge of the severe thunderstorm line, with periods of moderate to heavy rain reducing VIS significantly. Stratiform rain with isolated lightning strikes will linger behind the main convective line into early tomorrow morning. There is a potential (30-50%) terminals will see reduced VIS around 4SM and BR between 10z and 14z. && .EAX WATCHES/WARNINGS/ADVISORIES... MO...Flood Watch through Tuesday afternoon for MOZ020>022-028>033- 037>040-043>046-053-054. Flood Watch through Tuesday morning for MOZ001>007-011>016-023- 024. KS...Flood Watch through Tuesday afternoon for KSZ025-057-060- 102>105. && $$ DISCUSSION...BT AVIATION...WFO EAX  486 FXUS65 KLKN 181957 AFDLKN Area Forecast Discussion National Weather Service Elko NV 1257 PM PDT Mon May 18 2026 .KEY MESSAGES... * Temperatures will be cold with below normal readings at all locations today * A slow warmup will start today and persist through the rest of the week * Storm system will clip NV Thursday and Friday may bring a few isolated showers. * Memorial Day Holiday Weekend looking Quiet with light winds and highs in the upper 70s to upper 80s. && .DISCUSSION... (This evening through next Sunday) Quiet weather returns this week as NW flow aloft looks to keep NV dry, allowing for temperatures to warm back into the 80s by the Weekend. Overall weak troughing pattern over the interior Mountain west will keep northwesterly flow aloft over the great basin through next weekend. Monday through Wednesday look to be dry with light to breezy NW winds. Thursday a quick moving upper trough will ride the NW flow, bringing a wind shift line through Nevada, but models keep this system far enough to the NE that only the far NE Elko county could see a 10% chance for a light shower Thursday afternoon, this front will stall across central NV and this may be enough to generate a isolated shower for the mountains of N Nye county Friday. After Friday dry conditions return for the weekend lasting through Memorial Day. The main story this week will be the temperatures as the cold air mass left in the wake of Sundays storm system begins to modify and warm. Highs will start cool in the upper 50s to upper 60s Monday afternoon and warm through the week back into the mid 70s to mid 80s by Friday afternoon. Lows will gradually warm as well starting in the low 20s to low 30s Tuesday morning the rising back into the mid 40s to mid 50s by the Saturday morning. FORECAST CONFIDENCE & DEVIATIONS: There is high confidence for quiet, dry weather conditions with warming temperatures lasting through the Holiday weekend. There is low confidence for isolated showers across far NE NV Thursday afternoon, and for N Nye county Friday afternoon as a weak upper trough pushes a wind shift line through NV. && .AVIATION... VFR conditions are forecast through Tuesday evening with light to breezy afternoon northerly winds. KEKO remains AMD NOT SKED due to communication disruption. && .FIRE WEATHER... Low fire weather concerns over the next few days as northwesterly flow aloft keeps quiet dry conditions with warming temperatures for most of the week. A weak storm system will try and clip NV Thursday afternoon and Friday, however models want to keep this system well to our north, but there could be a low 10% chance for an isolated shower. Saturday through the Memorial Day holiday look to be quiet with highs in the upper 70 to low 80s. Winds will feature light to breezy afternoon winds, generally out of the WNW at 5 to 15 MPH with a few gusts up to 25 MPH possible. && .LKN Watches/Warnings/Advisories... None. && $$ DISCUSSION...98 AVIATION...98 FIRE WEATHER...98  541 FXUS66 KMTR 181958 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1258 PM PDT Mon May 18 2026 ...New SHORT TERM, LONG TERM, FIRE WEATHER... .KEY MESSAGES... Updated at 1251 PM PDT Mon May 18 2026 - Breezy to windy conditions, especially across the North, East, and South Bay Mountains and the Santa Cruz Mountains continue through tonight - Elevated fire weather concerns continue through today across the interior due to very dry conditions and breezy winds - Above normal temperatures continue through midweek with seasonal temperatures returning late week && .SHORT TERM... Issued at 1251 PM PDT Mon May 18 2026 (This evening through Tuesday) Gusty offshore winds have started to come down across the region and will continue to ease through the remainder of the day. Current gusts across the lower elevations are peaking around 25-30 mph with gusts across the higher elevations peaking between 35-45 mph. The strongest gust observed during this wind event was 86 mph right around midnight at Mt. Umunhum where the station is at an elevation of 3319 feet. This tracks pretty well with when the SFO-WMC pressure gradient peaked (-7.60 mb) around 1AM and again around 5AM. The SFO- WMC gradient is currently around -4.3 mb and is expected to continue easing through the remainder of the day. Winds remain lightly offshore across the interior through the remainder of today into tomorrow but winds will be weaker. We will see a return to our normal breezy afternoon/evening winds that ease overnight starting Tuesday. Upper level ridging continues to dominate the Pacific Ocean while broad upper level troughing prevails over the Western United States. At the surface, high pressure prevails over the Pacific while a coastal trough develops along the California coast. Warmer temperatures are expected to continue Tuesday through Thursday. This is thanks both to ridging offshore suppressing the marine layer and a warmer, drier airmass moving in in the wake of this weekend's strong offshore winds. Interior high temperatures will generally be in the 80s with the hottest portions of the North and East Bays in the low 90s. Coastal areas will be slightly cooler in the 60s to mid 70s. Dry conditions are expected to prevail through much of the upcoming week with daytime relative humidity values dropping into the 10's to 20's. While fire weather concerns are lower now that the winds are easing, fine fuels (grass, shrubs) are dried out and are ready to burn. If you are engaging in any outdoor activities involving flames or are towing something, keep a close eye on it and prevent sparks from spreading. && .LONG TERM... Issued at 1251 PM PDT Mon May 18 2026 (Tuesday night through next Sunday) The overall pattern remains the same for much of the upcoming week. High temperatures will stay above seasonal normals through Thursday with highs in the 80s to low 90s across the interior and 60s to 70s along the coast. Patchy moderate heatrisk is forecast across urban areas but it is note widespread enough to necessitate a Heat Advisory. If you are spending time outdoors this week make sure to drink plenty of water and take breaks in the shade as needed. Winds generally remain offshore with diurnally breezy conditions expected. Friday into the weekend a pattern change looks likely. Long range guidance suggests upper level ridging will weaken and shift westward over the Pacific while broad upper level troughing dominates the West Coast. With high pressure shifting away, onshore winds return and the marine layer will be able to redevelop by late week. A shallow (~500 ft) marine layer will redevelop mid to late week but will deepen to ~1000 ft by Friday. This, and receding high pressure, will kick off a cooling trend with interior temperatures returning to the 70s to low 80s and coastal areas to the 60s. The return of the marine layer will help to alleviate dry daytime conditions, further reducing fire risk late next week. && .AVIATION... (18Z TAFS) Issued at 1021 AM PDT Mon May 18 2026 VFR conditions prevail through the TAF period. Breezy and gusty northeast winds will gradually diminish through the next couple of hours as an onshore push returns to the coastal regions this afternoon, with the coastal breeze continuing through the evening. Breezy winds will continue across the interior mountains of the Bay Area through the night, with northeast winds spreading across the interior valleys Tuesday morning towards the end of the 24-hour TAF period. Beyond that, Tuesday's coastal breezes look to be stronger than today's. Vicinity of SFO... VFR conditions through the TAF period. Breezy and gusty northeast winds will turn more northwesterly through the afternoon, before diminishing through the evening and remaining light overnight through Tuesday morning. West-northwest winds will resume on Tuesday afternoon. SFO Bridge Approach... Similar to SFO. Monterey Bay Terminals... VFR conditions through the TAF period. Breezy northwest winds will develop imminently and continue into the evening. Winds remain light overnight before resuming Tuesday afternoon after the end of the TAF period. && .MARINE... (Today through Saturday) Issued at 1021 AM PDT Mon May 18 2026 Winds continue to diminish throughout the marine environment, but moderate to rough seas and moderate to fresh northwest breezes will still offer hazardous conditions for small craft into the mid weak before easing for most zones. Fresh to strong northwest breezes will remain hazardous for small craft into the late week for the northern outer zone. && .FIRE WEATHER... Issued at 1251 PM PDT Mon May 18 2026 Gusty north to northeast winds will continue through this afternoon before easing tonight into tomorrow. Peak gusts between 35 to 45 mph are still possible across the higher elevations into this evening. Daytime humidity retention remains poor with most sites staying around 10-25% across the interior and higher peaks with limited overnight recoveries. Winds ease by Tuesday but fire weather concerns will linger through late week as light offshore flow continues and daytime humidities remain poor. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Coastal Flood Advisory until 3 AM PDT Tuesday for CAZ506. PZ...Small Craft Advisory until 3 PM PDT this afternoon for SF Bay N of Bay Bridge. Small Craft Advisory until 9 PM PDT this evening for Mry Bay- Pigeon Pt to Pt Pinos 0-10 nm. Small Craft Advisory until 3 AM PDT Tuesday for Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 9 PM PDT Wednesday for Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory until 9 AM PDT Tuesday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...Kennedy LONG TERM....Kennedy AVIATION...DialH MARINE...DialH Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, X, and YouTube at: www.facebook.com/nwsbayarea x.com/nwsbayarea www.youtube.com/nwsbayarea