730 FXUS65 KCYS 182104 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 304 PM MDT Mon May 18 2026 .KEY MESSAGES... - Accumulating snow through Monday afternoon with Winter Storm Warnings for many of our high elevation and mountain zones and Winter Weather Advisories for nearby zones. - Near record cold Monday and Monday night will lead to widespread freezing temperatures, which may damage sensitive vegetation and outdoor irrigation systems. - Slow warming trend by the mid to late week with temperatures near normal by Thursday and Friday. Chance of showers and a slight chance of thunderstorms each day through Friday evening. && .SHORT TERM /THROUGH WEDNESDAY NIGHT/... Issued at 302 PM MDT Mon May 18 2026 On the backside of the strong system moving up into Nebraska we should see snow and precipitation beginning to subside into the evening hours. Strong pressure gradients did produce significant wind gusts and, combined with the heavy wet snow, near to blizzard conditions were noted this morning, particularly in Carbon County, shutting down I-80 and leaving several people without power across the area. Moving into this evening and overnight, we'll see concerns shift to cold temperatures as the cold airmass in place combined with snowpack or clearing skies helps to produce near to possibly record low temperatures. The entire forecast area is under a freeze warning due to this expected cold, with temperatures in the teens to mid 20's all the way through the Nebraska Panhandle. Cold sensitive plants, crops, and equipment will be impacted notably by this freeze. After this, look for a slow warming trend through Wednesday as our pattern advects warmer temperatures from the southwest as we stay generally under weak troughing aloft with southwesterly to westerly flow at 500mb prior to the next quick hitting system at the end of the week. Both Tuesday and Wednesday will feature small embedded shortwaves which could produce some scattered showers or possibly even a weak thunderstorm, but overall activity looks to remain minimal and fairly inconsequential. As temperatures steadily rise the region will slowly warm, but don't expect a quick shot of warmth. Highs Tuesday reach into the 40's to 50's outside of Carbon County where the lingering snowpack will likely keep the area cool in the 30's for the day. Tuesday night into Wednesday lows will once again descend into the 30's east of the Laramie Range, while to the west we'll see another hard freeze in the teens to 20's (also including Converse County to the north). A Freeze Watch has been issued for tomorrow night, with an upgrade to warning likely. Moving into Wednesday highs continue to recover into the 40's to 60's, with lows back into the 30's to 40's with sub-freeze temperatures once again west of the Laramie range. && .LONG TERM /THURSDAY THROUGH MONDAY/... Issued at 302 PM MDT Mon May 18 2026 Heading towards the end of the work week, a shortwave trough will push through Southeastern Wyoming and Western Nebraska on Thursday providing a source of large-scale forcing for ascent. Ensemble guidance has PWAT around the 75th percentile relative to climatology in addition to median SBCAPE around 300 J/Kg, so showers and thunderstorms are a good bet later in the afternoon and evening. Effective bulk shear is progged to range from 25-30 knots, so widespread severe thunderstorms are not expected, although can't rule out a few storms producing marginally severe gusty winds and hail. Given the increased cloud cover later in the day, high temperatures are expected to be 5-10 degrees below climatology in the 60s east of the Laramie Range, and 50s west. A secondary vorticity maximum will propagate across our region on Friday, combined with PWAT near the 60th percentile, resulting in another chance for a few showers and thunderstorms with little change in high temperatures from the previous day given the cloud cover. Into the weekend, 500 mb heights rise as weak longwave ridging establishes itself across the Rocky Mountain West, resulting in a warming trend and mostly dry conditions. High temperatures are expected to be near climatology (average high in Cheyenne on May 23 is 67 degrees), with 60s west of the I-25 corridor and 70s further east. The warm up will continue Sunday into Monday as the ridge axis shifts over Wyoming, resulting in above-average temperatures and little to no chances of precipitation. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1146 AM MDT Mon May 18 2026 IFR to LIFR in place for the Wyoming terminals as visibilities remain under 3 miles and CIGS remain at or below 2 kft. For the Nebraska terminals, MVFR to IFR remain especially in the vicinity of any heavier showers. Expect CIGS to gradually increase after 06Z as this winter storm wraps up with the exception of KLAR and KRWL where low clouds are expected to remain in place through 12Z in addition to blowing snow at KRWL. 15-20 knot NE winds will remain in place through 00Z, gusting to 25-30 knots before backing to NW after 06Z. As surface high pressure settles into the region behind the ongoing system, winds will decrease to around 10 knots. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Freeze Warning from midnight tonight to 10 AM MDT Tuesday for WYZ113. Freeze Warning from 8 PM this evening to 10 AM MDT Tuesday for WYZ101-102-106>108-115>119. Winter Weather Advisory until 6 PM MDT this evening for WYZ101- 105-106-110-111-115-117. Freeze Watch from late Tuesday night through Wednesday morning for WYZ101-115. Winter Storm Warning until 6 PM MDT this evening for WYZ103- 104-109-112-114-116. Freeze Warning until noon MDT Tuesday for WYZ104-105-109>111. Freeze Watch from Tuesday evening through Wednesday morning for WYZ104-105-109>111-113-116. NE...Freeze Warning from midnight tonight to 10 AM MDT Tuesday for NEZ002-003-020-021-054-055. Freeze Warning from 8 PM this evening to 10 AM MDT Tuesday for NEZ019-095-096. && $$ SHORT TERM...CG LONG TERM...NB AVIATION...NB  323 FXUS63 KLSX 182110 AFDLSX Area Forecast Discussion National Weather Service Saint Louis MO 410 PM CDT Mon May 18 2026 .KEY MESSAGES... - Widespread showers and thunderstorms are expected to continue into the evening with heavy rainfall in some locations potentially leading to flash flooding. - A few strong to severe thunderstorms are possible through the early morning hours of Tuesday with the main hazards being damaging winds, large hail, and a brief tornado or two. - Another round of thunderstorms are possible along a cold front Tuesday afternoon/evening. Damaging wind gusts and large hail are the primary threats. && .SHORT TERM... (Through Late Tuesday Night) Issued at 251 PM CDT Mon May 18 2026 Showers and thunderstorms from this morning laid out west to east on the upwind portion of the MCS. The outflow made it to a Crawford to Washington to Randolph County line before stalling. The 850 mb flow was out of the southwest this morning and has started to back from the south this afternoon. Simultaneously, a low level MCV ejected northeast out of Arkansas this afternoon. As this occurred, convection has begun to intensify on the northern side of the old outflow. Highest convective rates are currently just east of Columbia. Rainfall totals are already averaging 1 to 2 inches across the Flood Watch with isolated totals of 3 to 4 inches. This afternoon into evening, as the LLJ (or 850 mb flow) starts to slightly back and the the MCV ejects northeast convection will finally start to exit the region to the east. The break will be short lived though as another line of showers and thunderstorms will approach the region from the northwest this evening into early Tuesday morning. This line of storms will likely start to dissipate across central Missouri, but how quickly and exactly where matters regarding flood potential. The current thinking is for the line to weaken and dissipate near or just north of the St. Louis metro. However, a cold front will then approach the area from the northwest and cross the region Tuesday afternoon into evening. As this occurs, another round of showers and thunderstorms will develop. Damaging wind gusts and large hail appear to be the primary threat. After the final round of showers and thunderstorms moves across the area Tuesday evening, storm total rainfall amounts (from Monday morning to Tuesday evening) of 3 to 5 inches with isolated amounts of 6 to 8 inches appear likely. These amounts of rainfall will result in some flash flooding. Residents should monitor the latest forecasts and be prepared to seek higher ground if a Flash Flood Warning is issued for your area. BAH && .LONG TERM... (Wednesday through Next Monday) Issued at 251 PM CDT Mon May 18 2026 A surface cold front will be located across southern Missouri Wednesday with most of the region expected to be seasonably cool and dry. The one exception to this is across Reynolds, Iron and Madison counties were another round of thunderstorms will be possible close to the frontal boundary. Thursday into Friday, another mid-level wave will be located over the Mountain West with low level flow out of the southwest. As this occurs, the cold front will wash out with temperatures rising along with a return of showers and thunderstorms. The warm up will then persist into the weekend and early next week as another wave approaches from the west. This warming trend is supported by both the LREF and NBM IQRs. Looking at global ensemble guidance, a general building of mid-level heights is forecast to start this weekend across the Eastern United States and then retrograde west next week. BAH && .AVIATION... (For the 18z TAFs through 18z Tuesday Afternoon) Issued at 101 PM CDT Mon May 18 2026 A complex ofshowers and thunderstorms continues across central Missouri this afternoon. This round of thunderstorms has persisted since the overnight hours with almost continuous thunder at the TAF sites (except KUIN) since 12z. The line of thunderstorms has stalled just south of KCPS this afternoon with a shortwave wave currently near the Arkansas/ Missouri border. The shortwave is causing additional thunderstorm development just north of the boundary (or close to Columbia, MO). This means that all terminals will likely (>90% chance) observe thunderstorms through the remainder of the afternoon into the early evening. As the shortwave moves northeast of the region, showers and thunderstorms will begin to finally move east of the terminals with thunder temporarily ending from west to east. This break will be brief though. Another line of showers and thunderstorms will approach the terminals from the northwest Tuesday morning between 4 and 7 AM. This line of storms will likely weaken as they progress southeast, but the question is how quickly will they weaken. As of current, the thinking is the line of thunderstorms will hold together long enough to make it to KUIN, KCOU, and KJEF. It is unclear if there will be thunder at the St. Louis terminals. For now have only added SHRA (no thunder) for KSTL, KSUS, and KCPS. A cold front will then cross the terminals Tuesday afternoon with MVFR/ IFR cigs behind. BAH && .LSX WATCHES/WARNINGS/ADVISORIES... MO...Flood Watch through Tuesday afternoon for Audrain MO-Boone MO- Callaway MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO- Jefferson MO-Lincoln MO-Moniteau MO-Monroe MO-Montgomery MO- Osage MO-Pike MO-Ralls MO-Saint Charles MO-Saint Louis City MO-Saint Louis MO-Warren MO-Washington MO. IL...Flood Watch through Tuesday afternoon for Bond IL-Calhoun IL- Clinton IL-Fayette IL-Jersey IL-Madison IL-Marion IL-Monroe IL-Saint Clair IL-Washington IL. && $$ WFO LSX  772 FXUS66 KLOX 182117 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 217 PM PDT Mon May 18 2026 .SYNOPSIS...18/205 AM. Warmer temperatures are expected this week with some locally breezy Santa Ana winds this morning. The warmest day will be Wednesday with slow cooling the rest of the week along with a return of night and morning low clouds and fog. && .SHORT TERM (TDY-THU)...18/1234 PM. Another offshore push (although slightly weaker) is expected to develop tonight through Tuesday afternoon with wind gusts in the 30-40 mph range across the mountains, and 15-30 mph across the valleys and potentially the eastern edge of the Oxnard Plain. This mornings onshore push surfaced across the valleys and even some coastal areas. The Sandy Fire broke out this morning in Simi Valley and quickly burned through grassy hills due to gusty northeast Santa Ana winds. Even with slightly weaker winds, there again is an elevated threat for fire weather conditions tomorrow thanks in part to a prolonged warm and dry period. Winds will shift onshore Tuesday afternoon. Onshore flow will become more prominent Wednesday, increasing Thursday. Not expecting any marine layer coverage again until possibly late Tuesday through Wednesday, but more likely Wednesday night into Thursday morning as onshore flow becomes more pronounced. There is a very small chance that southern LA County, specifically the Long Beach area, sees low clouds and fog late tonight into Tuesday morning. Expecting all coastal areas and even some lower valleys to become entrenched in marine layer cloud coverage by Thursday night into Friday morning. High temperatures will increase 3-7 degrees tomorrow, and another degree or two in most areas Wednesday. By Wednesday, highs in the mid to high 80s will be common across coastal and interior valleys, with low 70s to low 80s common across coastal areas. A cooling trend begins Thursday on the coastal side of the mountains, while the interior will continue to warm a few degrees. .LONG TERM (FRI-MON)...18/1234 PM. A fairly quiet pattern will continue through the remainder of the forecast period, with weak winds aloft. Aside from a slight decrease in temperatures Friday and possibly Saturday, there will be little change in sensible weather day-to-day. Widespread temperatures in the 70s to low 80s will be common across coastal valleys and basins, slightly cooler at the immediate coasts with mid 60s to low 70s likely. Inland valleys will see highs reach the mid to upper 80s, with low 90s possible, especially Friday. A more robust marine layer is likely to develop each night through morning, with some coastal areas struggling to clear each day. Marine layer clouds will try to move into some of the coastal valleys by this weekend, as onshore flow increases into the weekend. Onshore flow will then stay relatively steady through Monday. Moderate southwest winds across the Antelope Valley and foothills by this weekend, which would lead to elevated fire weather concerns each afternoon in the far interior. && .AVIATION...18/1731Z. At 1633Z at KLAX, there was no marine layer nor an inversion. Overall, moderate to high confidence in 18Z Package. VFR conditions are expected. However, there is a moderate chance of MVFR CIGs at KLGB and KLAX 10Z-16Z Tuesday. KLAX...Moderate confidence in TAF. High confidence in VFR conditions through at least 06Z Tuesday. Moderate chance of MVFR CIGs around 015 from 10Z-16Z Tuesday. No significant east wind component expected. KBUR...Moderate confidence in TAF. No wind issues expected. && .MARINE...18/123 PM. For the Outer Waters, high confidence in current forecast. Small Craft Advisory (SCA) level winds and seas will linger through tonight. For Tuesday through Friday,winds and seas are expected to remain below SCA levels. For the Inner Waters north of Point Sal, high confidence in current forecast. From this afternoon through Friday, winds and seas are expected to remain below SCA levels. For the Inner Waters south of Point Conception, high confidence in current forecast. Through Friday, winds and seas are expected to remain below SCA levels. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory remains in effect until 3 PM PDT this afternoon for zones 88-375>380. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 3 AM PDT Tuesday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 9 PM PDT this evening for zones 673-676. (See LAXMWWLOX). && $$ PUBLIC...Lewis AVIATION...Black MARINE...Black SYNOPSIS...LP/MW weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox  722 FXUS66 KMFR 182116 AFDMFR Area Forecast Discussion National Weather Service Medford OR 216 PM PDT Mon May 18 2026 .DISCUSSION (Today through Sunday)... Key Points: * Minor impacts continue the next several days - Return of well above normal temperatures tomorrow - These above normal temperatures continue through the weekend * Drying trend continues through the extended forecast - No signal for precipitation in the forecast at this time * Elevated fire weather concerns this week - Combination of dry, breezy, and warm temperatures - Fuels fortunately keeping the overall fire threat low/moderate Further Details: A ridge of high pressure will maintain its position over the Pacific Ocean through the extended forecast. While occasional troughs pass over the northern tier of this high pressure, these will mainly impact Washington and southwest Canada. As a result, a dry and stable airmass is likely to persist this week. The position of the high and an area of low pressure inland will result in a strong pressure gradient over the forecast area (thermal trough) through this stretch, so expecting diurnal breezy afternoons each day. That said, it doesn't appear any hazards will result from these wind speeds. As we maintain the dry airmass and breezy afternoons, there will be at least an elevated threat for fire weather conditions each day. However, fuel conditions per fire agencies reveal the overall fire weather threat will remain low to moderate. Given the low RH values and breezy winds each afternoon, people should exercise caution with any outdoor activities that could cause sparks or flames. Bottom line is that fire season was declared early this year, so these precautionary actions should already be in place, but its especially important when we have these elevated fire weather days. Looking ahead, there is a chance for a change in the airmass around Memorial Day that could bring precipitation chances across the forecast area. This is technically outside of this forecast package, but something we will keep an eye on given the lack of precipitation lately. However, models are split on these chances so this is nothing of a "slam dunk" scenario. && .AVIATION (18Z TAFs)... VFR conditions are expected at all terminals throughout the valid TAF cycle. Northwesterly flow aloft is anticipated through this cycle as high pressure maintains over the Pacific. Main thing this cycle will be the breezy wind speeds this afternoon, but not expecting these speeds to continue after sunset with speeds decreasing overnight in a typical diurnal fashion. && .MARINE...Updated 200 PM PDT Monday, May 18, 2026...A thermal trough will bring gusty north winds and steep to very steep seas over the coastal waters much of this week. Winds will be strongest and seas will be highest during the afternoons/evenings. Through this stretch, very steep seas of 10-12 ft are most likely south of Cape Blanco with steep seas (6-9 ft) north of Cape Blanco. Ensembles indicate winds will strengthen Wednesday through Friday with a potential (35-55% chance) for gales (gusts) across portions of the southern waters, especially from around Gold Beach south. && .MFR WATCHES/WARNINGS/ADVISORIES... OR...CA...None. PACIFIC COASTAL WATERS...Hazardous Seas Warning until 11 PM PDT Wednesday for PZZ356-376. Small Craft Advisory until 11 PM PDT Wednesday for PZZ350-370. && $$  952 FXUS63 KIWX 182121 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 521 PM EDT Mon May 18 2026 .KEY MESSAGES... - Severe storms are anticipated again Tuesday afternoon and evening, with all hazards possible. - Warm and humid through Tuesday with highs in the mid to upper 80s. - Cooler with seasonable temperatures and dry midweek. Highs only in the 60s Wednesday and Thursday. && .UPDATE... Issued at 519 PM EDT Mon May 18 2026 Last portion of the broken line of storms was pushing through Allen county Ohio and will exit over the next 10 to 20 minutes. Behind it, the threat for any more thunderstorms has ended with no further concerns through tonight as the main cold front remains well to our west. Remainder of the watch will be dropped once the line clears the forecast area. && .DISCUSSION... Issued at 1014 AM EDT Mon May 18 2026 Main focus this forecast period is on the severe potential for today and on Tuesday. For today, seems the one limiting factor for today's storms will be the available shear, with values of Bulk Shear is around 20 to 30 kts, this should keep organization of storms minimal and current convective allowing guidance and thinking points to a more linear feature moving northeastward into the area over the next couple of hours from central IL. A plume of dew points in the mid 60s is pushing northeastward ahead of the convection currently pushing across central IL. Surface based CAPE values will run about 2000 to 2500 J/kg over the CWA. With environmental profiles drier near the surface and a moist plume maxing out around 850 mb this creates an inverted-V sounding which is indicative of gusty outflows/winds with thunderstorms this is further illustrated with Downdraft CAPE values around 1000 J/kg. Storm relative helicity values look to remain below the 100 m2/s2 threshold but there is the possibility for an isolated tornado or two. This first batch of storms will move through after Noon EDT and push through the area into this evening til around the 8 PM EDT timeframe. Moderate to heavy rainfall will accompany these storms with precipitable water value sitting around 1.70 inches. Of course, the storm motion speed will be important as if the line moves through quicker that will limit the rainfall amounts but either way looks like we should get a pretty good slug of rain with today's event as trailing stratiform will bring some moderate steady rainfall behind the initial line of thunderstorms as it pushes eastward through the area. Storm totals over the next two days looks to see some areas seeing close to an inch of new rainfall. A break in the action takes place tonight into the overnight period before the better looking set up arrives tomorrow in the form of a cold front associated with a low pressure circulation centered over northern WI. SB CAPE values will be around 1500-2500 J/kg, surface dew points will get into the upper 60s with a few locations seeing lower 70s, bulk shear values 30-40 kts, and mid level lapse rates around 6 deg/km and helicity values of 100-200 m2/s2. At this time it looks as if all threats will be on the table with the better helicity and shear values associated with the close proximity of the frontal boundary that will push eastward through the area. The exact timing is still a bit hazy but current indications have the frontal boundary approaching the western portions of our CWA around 1 PM EDT and exiting the area by early morning Wednesday. SPC currently has our entire area in a slight risk for severe thunderstorms for Tuesday. Heavy to moderate rainfall will once again be possible with the thunderstorms and as stated earlier that around 1 inch of new rainfall will be possible with these two batches of storms and locally heavier amounts if the residence times of thunderstorms linger. In the wake of the cold front a more zonal flow develops over the region on Wednesday and cooler and drier conditions will arrive. Highs on Wednesday will only get into the 60s which is about a 20 degree drop from the 80s today and Tuesday. Upper level ridging begins to push into the region by Thursday and will start to see a gradual increase in temperatures into the weekend. Highs Friday and Saturday will be in the 70s. Sunday into the beginning of next week highs will return int 80s. Chances for afternoon showers and thunderstorms will also increase over the weekend and at this time the best chances will be Friday afternoon and evening with a trough pushing through the area but periods of showers/t-storms will be possible each day into next week. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1149 AM EDT Mon May 18 2026 Primarily weather concern is an incoming squall line from the west. Observation stations have had episodes of G30KT, with at least one unofficial report of 58mph gust toward central IL. Timing was adjusted to TSRA to align with the latest storm motion. Behind this line, dry for the overnight hours unless stratiform rain back builds over KFWA (low confidence, but will monitor). Additional TSRA Tuesday, especially at KFWA, but just beyond this TAF period. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None. && $$ UPDATE...Fisher DISCUSSION...Andersen AVIATION...Brown  152 FXUS66 KSEW 182126 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 226 PM PDT Mon May 18 2026 .SYNOPSIS... The weather pattern remains fairly steady with high pressure situated offshore through the week with morning clouds and afternoon sun. Temperatures will rise a bit each day through the end of the week before beginning to cool off this weekend into early next week. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... North/northwesterly flow prevails across western Washington through the next several days, and with surface high pressure dominating offshore, the pattern remains pretty steady. Plenty of sunshine for most this afternoon with some mountain cumulus and a dissipating front approaching the coast. High temperatures this afternoon on track to reach the mid to upper 60s. This front will, however, be enough to bring a stronger onshore push tonight which will bring more widespread low stratus and some drizzly conditions across the area for Tuesday morning. Lows in the low to mid 40s. Clouds should slowly lift through the day but expect most of the day to be cloudy. Highs a little cooler, in the low to mid 60s. The upper level ridge offshore will begin to amplify and tilt onshore towards WA and BC, which will allow for a warming and sunnier trend to begin. With clouds expected to clear out early Wednesday morning, expect temperatures to be warmer, with highs reaching the upper 60s to low 70s. && .LONG TERM /THURSDAY THROUGH MONDAY/... The warming trend will continue through the end of the week, with the warmest temperatures across the region expected Thursday and Friday as the ridge traverses the area and more robust onshore flow begins to move in Friday into the weekend. Temperatures will top out Thursday and Friday into the low to mid 70s, with upper 70s to near 80 possible in the southwest interior and Cascade valleys. The ridge deamplifies as it moves eastward and shortwaves begin to move through it. This should help to not just start to cool temperatures, but also bring in clouds and chances for showers. Currently the best chances for showers will be Sunday night into Monday, but there is still considerable uncertainty given the trough's evolution/placement, or if the ridge will win out and push the trough elsewhere. 62 && .AVIATION... North to northwesterly flow aloft as upper level ridging remains over the region with onshore flow in the low levels continuing. All terminals seeing VFR this afternoon with some mid to high level clouds around. Light and variable winds will turn northerly after 00z and remain around 5 to 10 knots throughout the evening. Winds will switch to S/SW around 09z-12z and will maintain the same speeds. A weak system combined with onshore flow will have more widespread stratus develop early Tuesday morning, with likely MVFR/IFR conditions across area terminals. KSEA...VFR conditions this afternoon with light and variable winds turning northerly around 00z-03z. Speeds will increase slightly, generally remaining around to 5 to 10 knots throughout the evening. Winds will also turn S/SW around 11z-14z but maintain the same speeds. VFR will continue before stratus moves in at the terminal, bringing conditions down to MVFR (50 to 60% chance) through 19z-21z Tuesday. Conditions will rebound to VFR later Tuesday afternoon. Mazurkiewicz && .MARINE... Surface high pressure will remain over the northeastern Pacific throughout much of the week, bringing north to northwesterly winds over the coastal waters. A splitting weak system will cross over the waters tonight into Tuesday, bringing an increased period of onshore flow throughout the Strait of Juan De Fuca. A small craft advisory is in effect through Tuesday morning for increased westerlies. High pressure will rebuild midweek and continue throughout the rest of the week, which will provide continuous periods of onshore flow. Can expect in daily pushes down the Strait of Juan De Fuca through the rest of the week, which would likely generate small craft advisory winds. A weak system looks to enter the area waters Thursday into Friday. Coastal seas generally increasing to 6 to 8 feet through the first half of this week, with seas increasing more to 8 to 10 feet late Thursday and into Friday. Mazurkiewicz && .HYDROLOGY... The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated during this time as needed. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory until 5 AM PDT Tuesday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. && $$  429 FXUS64 KHUN 182142 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 442 PM CDT Mon May 18 2026 ...New AVIATION... .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... (00Z TAFS) Issued at 443 PM CDT Mon May 18 2026 VFR flight weather conditions are forecast. After 15Z Tuesday, southerly flow will increase to ~10kt with gusts of 15-20kt. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...GH SHORT TERM....KG LONG TERM....KDW AVIATION...17  700 FXUS64 KOUN 182145 AFDOUN Area Forecast Discussion National Weather Service Norman OK 445 PM CDT Mon May 18 2026 ...New AVIATION... .KEY MESSAGES... Updated at 443 PM CDT Mon May 18 2026 - There is a risk for strong to severe thunderstorms this afternoon through Tuesday. - Critical fire weather conditions are possible for far western Oklahoma into western north Texas this afternoon - Very warm temperatures are expected today with cooler weather by Tuesday. && .NEAR TERM... (Rest of today and tonight) Issued at 126 PM CDT Mon May 18 2026 Windy with potential fire weather across our far west and severe risks for storms are the headlines for today and tonight's period. The strong low-level jet overnight is not expected to weaken too much today as we could see wind gusts in the 40-50 mph as we continue to mix higher into the jet. A deepening surface low lee of the Colorado Rockies will maintain a tight pressure gradient across our area with south winds sustained at 20-25 mph. As a result our current Wind Advisory will remain in effect through this evening in areas generally west and north of the I-44 corridor. A dryline approaching our western CWA is expected to advance across the western one-tier of our counties in Oklahoma and adjacent northern Texas. As a result the fire danger potential will be increasing Near Critical to Critical risk west of the dryline due to very low afternoon RH's expected along with the gusty south winds and hot temperatures over still dry vegetation. A Red Flag Warning will be in effect this afternoon into the evening hours in that one-tier of counties west of the dryline. As far as storms, there is a 20-25% probability for convection firing up along and east of the dryline as forecast soundings suggest diurnal heating eroding the mid-level cap. Should any storms initiate they would be growing in strongly unstable (3000- 5000 J/kg) environment. Although deep-layer shear may be weak this afternoon in our area but expected to increase tonight along with the low-level shear as the low-level jet strengthens. Although the overall highest severe risk will be highest across the Central Plains the risk will extend into the Southern Plains with an Enhanced risk across northern Oklahoma to a Slight risk covering all but our far southeast CWA. Should any dryline convection initiate there is a potential for supercells producing large hail and damaging wind gusts and a conditional risk for a tornado with that risk highest closer to the Central Plains in northern Oklahoma. Storm POPs increase late tonight up to 80% with a cold front coming down the Central Plains advancing into northern Oklahoma late this evening pushing across the remainder of our forecast area through the early morning hours. Todays severe risks and associated hazards will be remain unchanged for tonight in the warm sector along and ahead of the cold front as the shear will be increasing. && .SHORT TERM... (Tuesday through Wednesday night) Issued at 126 PM CDT Mon May 18 2026 By sunrise Tuesday expecting the cold front & storm activity to be near the I-44 corridor and continue pushing south and east. Storm POPs will remain high up 60-90% along the front during the remaining morning hours but more restricted to southeast Oklahoma in the afternoon with the cold front eventually exiting our area. The severe risk remains along the cold front into Tuesday afternoon with the hail & wind hazards remaining although the tornado risk will be very low. High surface pressure starts building in behind the cold front with lighter north winds advecting much cooler air down through the Great Plains. Although the coolest air may lag reaching southeast Oklahoma and our Texas counties for a day, the remainder of our area will see milder unseasonably cooler temperatures with highs near 70 degrees with the muggy air restricted to southeast Oklahoma. Although our area will be post-frontal by Tuesday evening, the main systems upper trough will remain opened across the western U.S. through this week with a series of short-wave disturbances expelled downstream over the Southern Plains each day producing elevated-based convection. The first of these disturbance will increase storm chances Tuesday evening and overnight across our area. Although the ECMWF is less aggressive with the elevated instability, the NAM suggests these elevated storms could produce severe hail & winds overnight. For Wednesday all of our area will feel milder with highs in the lower to mid 70s becoming chilly with overnight lows in the 50s to low 60s and storm chances again increasing overnight. && .LONG TERM... (Thursday through Sunday) Issued at 315 AM CDT Mon May 18 2026 An active subtropical jet stream (STJ) with subtle waves lifting into the Southern Plains will result in a daily chance of showers/storms through the end the week into next weekend. At this time, there is no day that has an appreciable risk for severe weather. Temperatures are expected to be seasonable for late May. Mahale && .AVIATION... (00Z TAFS) Issued at 443 PM CDT Mon May 18 2026 Showers and storms are expected to move in with a cold front late tonight into tomorrow. Winds will shift to the north behind this boundary, as will reduced ceilings through the remainder of the TAF period. There is the potential for addition storms this afternoon and evening along western Oklahoma and western north Texas, but confidence in affecting any TAF site is low at this time. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 61 70 55 71 / 60 40 60 30 Hobart OK 60 72 54 73 / 60 20 50 20 Wichita Falls TX 68 81 58 76 / 20 80 70 40 Gage OK 49 72 46 70 / 20 0 10 10 Ponca City OK 58 69 52 70 / 80 20 30 10 Durant OK 74 84 64 78 / 10 90 60 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...Red Flag Warning until 9 PM CDT this evening for OKZ004-009-014- 021-033-034. Wind Advisory until 10 PM CDT this evening for OKZ004>027- 034>038. TX...Red Flag Warning until 9 PM CDT this evening for TXZ083-084. && $$ NEAR TERM...68 SHORT TERM...68 LONG TERM....10 AVIATION...13  803 FXUS65 KTWC 182146 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 246 PM MST Mon May 18 2026 .SYNOPSIS...A storm system tracking to our north across the Great Basin will result in breezy conditions and below normal high temperatures across southeast Arizona today. High temperatures warm to near normal by Wednesday and remain there into next weekend. && .DISCUSSION...So far today breezy to locally windy conditions have been observed across southeast Arizona under hazy skies. Sustained winds of 10-20 mph with occasional gusts to 25-30 mph have been measured with locally higher gusts along the New Mexico border in Cochise County. Windy conditions over the past few days has contributed toward the hazy skies. Breeziness will continue this afternoon resulting in near critical fire weather conditions for areas mainly south and east of Tucson. More details in the fire weather section below. Overall, today has the feel of another one of those windy Sonoran Desert days where trash cans and patio furniture might not want to stay upright with the sky looking a bit hazy from being all stirred up. Afternoon breezes will begin to taper shortly after sunset but return again tomorrow through Wednesday afternoon for areas mainly south and east of Tucson. Wind speeds are forecast to be lighter compared to the last few days, so little to no impacts are expected. As for temperatures, this afternoon highs will top out in the mid to upper 80s or about 5 to 10 degrees below normal. Wednesday, we will see temperatures warm back up closer to normal (upper 80s to low 90s) which will continue into the weekend. By this weekend into early next week, ensembles are trying to introduce rather modest mid-level moisture (between 0.5-0.8 inches of precipitable water) in conjunction with a upper low. If this pattern occurs it may bring increased breeziness, nonzero chances for precipitation, and temperatures trending near normal late this week into early next week. Given how dry it has been and how dry it usually is this time of year, my hunch is that it will be tough to see much in the way of measurable precipitation from this system without gradual moistening of the atmosphere from the top-down. With that in mind, I would expect predominantly virga and cloud buildups from this system if it comes to fruition with perhaps a low end chance (10-15%) for an isolated dry thunderstorm. The NBM currently advertises a slight chance (10-20%) for precipitation focused over the terrain mainly south and east of Tucson and in the White Mountains from Saturday through early next week. That being said, unless there is more evidence that moisture will indeed get wrapped up into the system, my confidence for widespread precipitation chances remains on the low end. Something to keep an eye on ahead of the weekend. && .AVIATION...Valid through 20/00Z. Mostly SKC-FEW thru the valid pd with ocnl thin high level cirrus AOA 20k ft AGL. SFC winds WLY/SWLY at 11-19 kts with gusts between 25-30 kts. Highest winds expected south/east of KTUS in the vicinity of KDUG thru 19/03Z. Thereafter, SFC winds primarily terrain driven at less than 8 kts until picking and becoming WLY/SWLY again after 19/17Z with speeds of 9-17 kts and ocnl gusts to 22-26 kts. && .FIRE WEATHER...Breezy to locally windy conditions (sustained winds 15-20 mph; gusts between 30-35 mph) combined with low relative humidity (as low as 13 to 18 percent) and dry fuels this afternoon will result in near critical fire weather conditions across eastern portions of Cochise County. Winds will taper off after sunset and RH will recover to between 40 and 50 percent overnight. Tomorrow and Wednesday, elevated fire weather conditions are forecast (especially for southeast portions of Cochise County) as breezy conditions (winds around 15 mph; gusts 25-30 mph) and minimum RH (between 10 to 15 percent) continue thru Friday afternoon. While confidence remains low, there is a slight chance (10-20%) for cloud buildups and virga over the weekend into early next week in the White Mountains and terrain over to the south and east of Tucson. Stay tuned. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ DVS Visit us on Facebook, X, YouTube...and at weather.gov/Tucson  151 FXUS65 KVEF 182155 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 255 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 00Z Forecast Package...Wind speeds are expected to drop to 6-8KT through Tuesday morning, backing from the northeast this evening to the north overnight. By mid-morning Tuesday, winds increase to 10-12KT, shifting to the northeast with intermittent gusts to around 20KT expected into early afternoon. Gusts will diminish a bit more quickly on Tuesday, with northeasterly winds around 8KT expected to become light, backing to the northwest through the evening. VFR conditions will continue. For the rest of southern Nevada, northwest Arizona and southeast California...For the 00Z Forecast Package...Elevated northeasterly winds will continue diminishing through sunset, with wind speeds across the region dropping to 5-10KT overnight as winds back to the north and northwest with some variability. By mid-morning Tuesday, winds veer to the northeast, increasing to 10-15KT with gusts to around 20-25KT expected through mid-afternoon, mainly across southern Nevada and northwestern Arizona. Through the Lower Colorado River Valley from KIFP to KEED, northerly winds Tuesday will be enhanced by terrain, with speeds 15-20KT and gusts to 25-30KT through mid- to late afternoon before diminishing. VFR conditions will prevail, with a few high clouds impacting southern areas Tuesday late morning into the afternoon. && .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  324 FXUS65 KPIH 182158 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 358 PM MDT Mon May 18 2026 .KEY MESSAGES... - A very chilly overnight tonight in the Snake River plain and eastern Magic Valley. Frost and Freeze bulletins have been issued. - Some precipitation, including Thursday afternoon thunderstorms, is possible starting Tue evening and continuing through Thu afternoon. - Weaker wind until the weekend. && .DISCUSSION... Issued at 143 PM MDT Mon May 18 2026 Tonight through Thu afternoon...Save for some showers in the extreme southeast corner of the forecast area, the next 24 hours will continue to be dry, cool to cold, and windy. This is due to an upper level trough currently in WY still pushing slowly eastward. The clear skies and continued northerly airflow means a quite cold overnight tonight, with 20 to 30 degrees expected in the Snake River plain. With the northerly flow not as strong in the eastern Magic Valley, temperatures are only expected to bottom out tonight in the middle 30s. These two reasons are why a Frost Advisory has been issued for the two Magic Valley zones and a Freeze Warning once again for all zones in the Snake River plain. The start time was mostly based on when the affected zones finally lose this strong wind tonight, which is still actually fairly late. By 19/15Z 19/0900MDT the temperatures should surge back above Freeze and Frost thresholds. The north wind is expected to shift to a southwest wind and not be as problematic for the Snake River plain for Tue. The light northerly wind in the morning will shift to a south to southwest wind for the afternoon, ending the need for a Lake Wind Advisory on Tue. This lighter south to west wind continues Wed, then a northerly wind returns for Thu. It doesn't take much for a Lake Wind Advisory to be needed in the north flow regime, so it may return. Finally, impulses moving through the northwest to west upper air flow will return on Tue night. This will mean showers over the north end of the forecast area that night, then a further digging southward will spread precipitation from a close low in central MT for heavier rainfall on Wed night and Thu morning. The precipitation will be mainly focused on the central Idaho mountains and the southern and eastern highlands, with the northern end of the Snake River plain most likely to see precipitation in the lower elevations. While isolated thunderstorms are possible Tue and Wed, Thu includes the associated cold front with this MT low actually coming through and generating high chance of thunderstorms. Since the afternoon has more unstable air, the best threat is in the eastern third of the forecast area. Thu night through next Mon...The low clears out early enough on Thu that while it is colder, the sunny skies of Fri should allow a warming trend to develop quickly. By Sat afternoon temperatures should soar above normal after a near normal Fri afternoon. A gradual warming trend continues at least into Mon, for both highs and lows. Weak troughing gets replaced by weak upper level ridging, which will allow some breezy westerly wind, but doesn't appear to bring an significant precipitation. It appears to be fairly limited to higher elevations that can provide lifting with west-facing slopes in the zonal flow, especially Fri and Sat. Only a minority of the solutions cluster around a wet scenario for eastern Idaho. This accounts for the warming trend. The zonal flow tightens starting Sat, so it will likely be breezy to windy for Sat/Sun/Mon, at least in the afternoon. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 346 PM MDT Mon May 18 2026 VFR conditions are expected through the forecast period. Gusty N/NE winds remain in place for the Snake Plain/Teton Valley terminals and these will continue into the early evening before beginning to taper off, becoming more light and variable overnight and into Tuesday morning. KSUN will see more of a northwesterly wind component this afternoon and continuing into the evening. KBYI will see a more westerly wind component this afternoon and early evening and not nearly as breezy as the other locations. Not expecting any precip at terminals through the period with skies becoming more clear into Tuesday morning. By Tuesday afternoon overall light southwest winds return and Mid-level SCT to BKN clouds return.| && .PIH WATCHES/WARNINGS/ADVISORIES... Frost Advisory from 3 AM to 9 AM MDT Tuesday for IDZ051-055. Freeze Warning from midnight tonight to 9 AM MDT Tuesday for IDZ052>054. && $$ DISCUSSION...Messick AVIATION...TW