089 FXUS61 KRNK 182209 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 609 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... Just enough instability along the western slopes for an isolated shower or thunderstorm to form early this evening. Increased PoPs along the western counties (Tazewell to Western Greenbrier). && .KEY MESSAGES... KEY MESSAGE 1: The heat wave continues with record-breaking heat possible through Wednesday before cooler weather returns late week. KEY MESSAGE 2: Multiple opportunities for precipitation following the cold front on Wednesday. && .DISCUSSION... KEY MESSAGE 1:The heat wave continues with record-breaking heat possible through Wednesday before cooler weather returns late week. Southerly flow will persist across the Eastern CONUS through Wednesday due to a large Bermuda high in the western Atlantic. Although moisture at the surface has increased due to this flow, an upper-level ridge has also strengthened and is suppressing convection due to the drier air aloft. This synoptic setup will allow temperatures to remain 15-20 degrees above normal for this time of year, with highs in the 80s for the mountains, and low to mid 90s for the Piedmont today and Tuesday. Temperatures are already in the low 90s in parts of the Piedmont just after midday. Therefore, some record highs may be in jeopardy today and tomorrow. A cold front approaches the area on Wednesday, which will keep highs a few degrees cooler in the mountains, though still in the 80s as showers/storms move in late in the day. However, ahead of the front in the Piedmont, highs will likely reach the mid 90s. Although heat indices will not be dangerously high during this heat wave, it has been nearly a year since temperatures have been over 90 degrees for several days in a row. Stay hydrated, limit outdoor activity, and wear light and loose fitted clothing to help reduce the risk of heat illnesses. Relief from the heat arrives by Thursday, once the cold front moves into the area, with much cooler weather and highs in the 60s/70s the remainder of the work week and into the weekend. KEY MESSAGE 2: Multiple opportunities for precipitation following the cold front on Wednesday. A Bermuda high pressure looks to develop and remain quasi- stationary across the western Atlantic through the beginning of next week. This will maintain southerly flow and a summer like pattern in place across the region as moisture is advected north into the Southeast from the Gulf and Atlantic. As moisture finally moves into the region, PWATs generally look to recover into the 1.0-1.5 inch range areawide. With ongoing drought conditions, these conditions bode well for multiple rain opportunities over the next week or so starting Wednesday. On Wednesday, a cold front is expected to approach the region from the northwest as an upper level trough and associated surface low pressure system slide east through southern Quebec and Ontario. The lagging cold front looks to provide some forcing for shower and thunderstorm activity, with modest deep layer shear in the 20-30 knot range Wednesday afternoon. This amount of deep layer shear combined with instability values in the 500-1000 J/Kg will likely lead to some multicellular clusters of thunderstorms through the afternoon and evening across the region. With these shear and instability values, some hail and damaging wind gusts can't be ruled out across the area. With this potential, SPC has introduced a Marginal Risk (level 1 of 5) for severe weather for portions of central Virginia on Wednesday. By Thursday, this frontal boundary looks to stall across the region providing some forcing for ascent across the region. The presence of mid level disturbances progressing east along the frontal boundary combined with a southward sagging 250mb jet streak looks to increase deep layer shear slightly on Thursday. This may lead to another day with possible severe weather chances as instability looks to remain elevated as well. Beyond Thursday, the aforementioned Bermuda high looks to continue to remain over the western Atlantic, which will keep the moist airmass over the Southeast. Mid-level disturbances look to continue to slide east over the region, which will keep rain chances in the forecast each day through the weekend and into the early portion of next week, likely bringing much needed and beneficial rainfall to the area. While its hard to imagine currently with the drought, if the area does receive repeated heavy rainfall, during this period, the flash flood threat may increase across the area; however, these chances will need to be monitored through the week as these systems move over the region. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... With dewpoints remaining low through Tuesday morning, early morning fog doesn't look as likely to develop at LWB like it has the last two mornings. Given this dry trend, fog has not been included in the TAFs at this time for LWB. Therefore, VFR conditions are expected to remain at all terminals through the TAF forecast period. Winds will generally remain out of the south/southwest through the TAF period at around 10 knots or less. Wind gusts the next two afternoons looks to increase to around 15-20 knots at all terminals. EXTENDED AVIATION OUTLOOK... High pressure will keep the weather quiet and conditions VFR through the beginning of the week outside of any river valley fog that may develop. This river valley fog may lead to some brief periods of restrictions due to lowering VSBYs at LWB. More widespread rain and scattered thunderstorms are expected starting Wednesday with the approach of a cold front. Rain and storm chances and cloud cover linger through the end of the week with the system possibly stalling across the area. This may lead to sub-VFR conditions through the end of the work week. Note: Bluefield (KBLF) ASOS is currently experiencing a technical outage due to a major power supply failure. Replacement parts have been ordered. ETA of repair is currently unknown. AMD NOT SKED is being appended to its TAF. && .CLIMATE... Record-breaking heat is possible early next week. Here are the current records and our current forecast. Monday, May 18, 2026 Station Hi Max T Hi Min T Forecast High Roanoke 94 in 1962 69 in 1996 94 Lynchburg 93 in 1911 68 in 1894 93 Danville 93 in 1974 69 in 2015 94 Bluefield 87 in 1996 66 in 2015 86 Blacksburg 88 in 1911 61 in 2018 90 Tuesday, May 19, 2026 Station Hi Max T Hi Min T Forecast High Roanoke 96 in 1962 69 in 2022 94 Lynchburg 93 in 1962 66 in 2022 93 Danville 95 in 1962 69 in 1962 95 Bluefield 89 in 1911 66 in 1977 86 Blacksburg 91 in 1911 61 in 1938 90 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ DISCUSSION...EB/JCB/RCS AVIATION...EB CLIMATE...RCS  350 FXUS65 KRIW 182210 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 410 PM MDT Mon May 18 2026 .KEY MESSAGES... - Snow and wind (up to 60 mph) remain for portions of central and southern Wyoming, including around Lander, Casper, South Pass, and Interstate 80. Conditions should slowly improve through he remainder of the day, with any light precipitation ending by midnight. - Warming trend Tuesday and Wednesday, with mostly dry conditions. Another weather system brings cooler temperatures and precipitation chances for Thursday. - Currently looking favorable for warm and dry weather this coming holiday weekend. && .UPDATE... Issued at 1235 PM MDT Mon May 18 2026 The snow and wind across the area has been mostly as forecasted. Greatest impacts were around South Pass and I-80, with winter travel impacts going into this afternoon. Conditions should slowly improve through the evening as snow decreases and winds diminish. As was the trend in the day leading to the start of the event, northern locations have not seen as much (or any) snow, so have ended the advisories there early. As the system exits, very cold temperatures remain in place, with lows tonight in the upper teens to mid-20s for a majority of the area. Cooler temperatures remain in place Tuesday and Tuesday night, with a very gradual warm up into the end of the week. && .DISCUSSION... Issued at 240 AM MDT Mon May 18 2026 Rain changed over to snow in the Wind River Basin and across Sweetwater County just a few hours ago after 11pm Sunday night. Much of Natrona County is around 37F degrees as of 08Z (2am), with precipitation still falling as rain. The forecast remains on track this morning, with the threat of snow and wind impacting areas from South Pass southward into Sweetwater County. The 700mb low from this storm system will be passing close to the CO/WY border this morning, resulting in a tight temperature and pressure gradient. 700mb northeast winds of 50-60kt will occur from the Green Mountains/Rattlesnake Range into Sweetwater County. This will result in wind gusts of 60 to 70 mph occurring this morning over locations like South Pass down to the Rock Springs/Green River area. Windy conditions (wind gusts up to 35 mph) will be widespread across the CWA this morning as the storm system moves over CO this morning. Snowfall amounts of 2 to 6 inches is still expected across portions of Natrona County, the Lander Foothills and the eastern half of Sweetwater County. Travel conditions could be difficult this morning due to the blowing snow and icy roads. Impacts from snow accumulations on roads is likely to only last through 15Z/16Z (9am or 10am) as it will be more difficult for the snow to stick due to the high sun angle. These impacts will begin to decrease through the morning, with areas like Lander and Casper improving first as snow begins to end toward midday. Impacts along I-80 will last the longest due to the proximity of the 700mb low, but is expected to wane between 18Z and 21Z as snowfall ends. Winds will be decreasing across the area after 18Z as well, with the stronger winds of 35 to 40 mph continuing from South Pass southward into Sweetwater County and decreasing through the afternoon. Needless to say, temperatures will be anywhere from 5 to 25 degrees colder today and about 15 to 30 degrees below normal. Winds will continue to decrease this evening, as the storm system quickly exits over the Central Plains and light winds (10kt or less) expected for most areas by 06Z Tuesday. Fog development could occur as late as sunrise Tuesday morning as clouds are expected to remain in place across central and southern portions of the CWA through much of the night tonight. Dry and warming conditions are expected Tuesday and Wednesday, with another Canadian storm system impacting the area on Thursday. This system doesn't look to be as cold as today's storm and snow levels staying around 7000ft at this time. Model guidance remain split at this time, but confidence is medium for a mainly dry holiday weekend for at least 2 of the 3 days. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 410 PM MDT Mon May 18 2026 A spring system will continue to impact the area through this evening. Several terminals will continue to see lingering MVFR to IFR snow impacts. Most persistently will be KBPI and KPNA, which should see IFR conditions through around 06Z. East of the Divide, KCPR is expected to hold on to impacts the longest. Confidence for additional impacts at remaining terminals is lower, with KLND and then KRIW most likely to see occasional MVFR to IFR impacts as snow lingers in the Wind River Basin. This activity is expected to wane everywhere after 06Z, with clouds decreasing from west to east overnight. If skies clear quick enough fog may be an issue at several terminals after around 10Z. For now, we are most confident at KBPI and especially KRKS, though fog potential will also need to be watched for at KCPR, KLND, KPNA, and KRIW. Any low clouds should lift by late Tuesday morning, with VFR conditions expected across the area through Tuesday afternoon. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .RIW WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 6 PM MDT this evening for WYZ014- 026>029. Winter Storm Warning until 6 PM MDT this evening for WYZ015- 018>020-022-030. && $$ UPDATE...Wittmann DISCUSSION...LaVoie AVIATION...Myers  133 FXUS63 KGLD 182225 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 425 PM MDT Mon May 18 2026 .KEY MESSAGES... - Scattered light rain showers through early evening. - Frost possible Tuesday morning west of Highway 25 as temperatures fall into the low to mid 30s. - Occasional shower chances through the rest of the week, perhaps a few isolated thunderstorms Thursday and Friday. && .SHORT TERM /THROUGH THURSDAY NIGHT/... Issued at 1245 PM MDT Mon May 18 2026 Low clouds, drizzle and light rain showers covering much of the area this morning will slowly erode on the southern edge through this afternoon, with the latest HRRR showing clearing as far north as Interstate 70 by 22z. Afterwards, the clouds will push south again and they will persist through much if not the entire night. Deepening low pressure in southwest Kansas will result in northwesterly winds gusting to 30-40 mph generally south of Interstate 70 between 00-06z, then gradually decreasing overnight. Chance for any light showers will end with the wind shift. Due to the persistent clouds and wind, temperatures will likely only drop into the low to mid 30s for lows, so issued a Frost Advisory to account for that. Clouds will finally dissipate Tuesday morning leaving a mostly sunny and milder day with highs mainly in the 60s. Next shortwave trough will come out of Colorado Tuesday night, and combined with surface winds turning to east and southeast will result in scattered light rain showers. Overnight precipitation amounts will be less than a tenth of an inch. The showers will continue to increase in coverage Wednesday morning as additional shortwave energy moves out of Colorado in the persistent southwest flow aloft. Weak instability in the afternoon is limited to the immediate vicinity of the Front Range and not expecting any thunder here. QPF remains light through the day on Wednesday, but there is a modest increase Wednesday night, with SREF/NBM means showing generally up to a quarter of an inch, but some deterministic output suggesting locally up to a half inch or more. High temperatures will be in the 50s and 60s with the clouds and precipitation, coolest in Colorado. Thursday will see a stronger disturbance move out of the northern Rockies into western Colorado by the afternoon, then moving across the area Thursday night. Shower and thunderstorm chances will increase once again. Instability will be limited by cloud cover, and models showing only weak SBCAPE of around 500 j/kg in the afternoon, mainly in Colorado. Deep layer shear will increase to 30-50 kts by 00z and may compensate somewhat for the weak instability in Colorado, where a marginally severe storm may be possible through the early evening before loss of heating. Scattered showers and isolated thunderstorms will continue through Thursday night as the upper wave makes its way across the area. Additional rainfall amounts Thursday night are generally between 0.25" - 0.50", though locally higher amounts over 1" are possible. Temperatures on Thursday could remain in the 50s, especially north of Interstate 70, where clouds persist through the day, with perhaps 60s further south or west with limited clearing. && .LONG TERM /FRIDAY THROUGH MONDAY/... Issued at 255 PM MDT Mon May 18 2026 Friday, our region is forecast to be under a weak southwest flow with a weak trough west of the Rocky Mountains. There is also a surface low forecast to set up somewhere in southwest Kansas. Ensembles do not fully align on the placement of this surface low. High temperatures are forecast in the 60s to low 70s. Chances for showers and thunderstorms continue throughout the day as embedded shortwaves pass through the region. Probability of Precipitation (PoPs) are 30-60% increasing from southwest to northeast. The environment is forecast to be moderately unstable with CAPE values generally between 500-1000 J/kg for the region. However, lingering cloud cover will likely keep the environment capped, reducing the risk for severe weather. If thunderstorms are able to form, small hail could occur with stronger storms. Skies will clear out Saturday and begin a slight warming trend through the beginning of the work week. High temperatures are forecast in the 70s for Saturday and the 80s for Sunday and Monday. Saturday will have a 25% chance for showers and thunderstorms for the southeast county warning area (CWA) from weak shortwave passages. After Sunday, we transition to more of a ridge pattern, so expect primarily sunny skies and gusts up to 30 mph in the afternoons for our Colorado counties. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 422 PM MDT Mon May 18 2026 IFR will prevail through this evening and into the overnight at both KGLD and KMCK due to low ceilings. Northerly surface winds will gust up to 30kts at times through this evening, gradually diminishing overnight. Ceilings will begin to lift and dissipate around 12z at both terminals, perhaps slightly earlier at KMCK, with a return to VFR by mid to late Wednesday morning. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...Frost Advisory from midnight MDT /1 AM CDT/ tonight to 8 AM MDT /9 AM CDT/ Tuesday for KSZ001-002-013-014-027-028-041- 042. CO...Frost Advisory from midnight tonight to 8 AM MDT Tuesday for COZ090>092. NE...Frost Advisory from midnight MDT /1 AM CDT/ tonight to 8 AM MDT /9 AM CDT/ Tuesday for NEZ079-080. && $$ SHORT TERM...024 LONG TERM...Rhoades AVIATION...024  425 FXUS64 KOHX 182231 AFDOHX Area Forecast Discussion National Weather Service Nashville TN 531 PM CDT Mon May 18 2026 ...New AVIATION... .KEY MESSAGES... Updated at 528 PM CDT Mon May 18 2026 - Above normal temperatures in the upper-80s to low-90s continue through Tuesday. - There is a high chance for showers and storms Tuesday night into Wednesday. The severe threat is very low. - Additional rain chances late week may push rainfall totals over 2 inches by the end of the week. && .SHORT TERM... (Rest of today through Tuesday) Issued at 1118 AM CDT Mon May 18 2026 Not much in terms of cloud cover over Middle Tennessee currently, but clouds are approaching from the west and the south this afternoon. We're already in the 80s in a lot of areas across Middle Tennessee, with highs expected to top out in the low 90s. We could possibly see a stray shower or thunderstorm from the convection to our north and west this evening, but that probability is very low at this time. Tuesday will be the start of a pattern shift in the area. Through the end of the week, Middle Tennessee will be stuck in a troughing pattern with several systems coming through. The good news is it looks to bring some much needed rainfall to our yards, with QPF through the end of the forecast period around 1.5 to 2.3 inches. The bad news is there is a severe threat associated with a cold front Tuesday afternoon into Wednesday morning. The severe threat is a marginal risk, level 1 out of 5, but not impressive. Any severe weather we get in Middle Tennessee with this will be pretty isolated, as the better parameters for more widespread severe are displaced to our northwest again. Despite cloud cover, southerly flow will raise our temperatures into the 90s once again for highs on Tuesday before the cold front swings through. && .LONG TERM... (Tuesday Night through next Monday) Issued at 1118 AM CDT Mon May 18 2026 Our unsettled weather continues mid-week, with our highest rain chances Wednesday. As the cold front passes through and high pressure sets up to the north, expect rainy conditions all day on Wednesday. While it will be a soaker, severe weather is not a concern at this time. The cold front will slowly pass through Middle Tennessee into Wednesday night, and is expected to stall out just to our south in northern Mississippi and Alabama. This will lead to another higher rain chance south of I-40 Thursday afternoon and evening. PWATs will remain on the higher side through the forecast period, and probabilities of greater than 2 inches of rain by the end of the weekend are still around that 50-70% range. We will continue to cross our fingers and hope the rain totals don't decrease! Temperatures will drop a little after the front to the upper 70s and low 80s, but that's about it for the remainder of the forecast period. && .AVIATION... (00Z TAFS) Issued at 528 PM CDT Mon May 18 2026 VFR conditions expected for this TAF cycle, however I have added in a PROB30 for CKV late tomorrow afternoon now that we finally look to have some storms in the area. Time may have to be adjusted slightly with future issuances based on latest guidance. Southerly winds will relax below 10 kts after 00Z, then become gusty again late tomorrow morning with gusts of 20 to 25 kts. && .PRELIMINARY POINT TEMPS/POPS... Nashville 71 91 67 83 / 10 20 60 100 Clarksville 72 90 66 80 / 0 40 80 90 Crossville 66 84 64 81 / 0 10 40 90 Columbia 70 90 66 83 / 10 20 50 90 Cookeville 69 87 66 81 / 0 10 40 90 Jamestown 66 88 64 83 / 0 10 40 90 Lawrenceburg 70 87 67 82 / 10 10 60 90 Murfreesboro 71 90 67 84 / 10 10 60 100 Waverly 73 90 68 81 / 0 30 70 90&& .OHX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Holley LONG TERM....Holley AVIATION.....Unger  582 FXUS61 KCTP 182235 AFDCTP Area Forecast Discussion National Weather Service State College PA 635 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... * Day 2 SPC Outlook upgraded to a Slight Risk (Level 2 out of 5) for damaging winds in northwest PA. && .KEY MESSAGES... 1) Hottest temperatures of the year so far forecast this afternoon along with some scattered storms in south central PA. 2) More heat & humidity will produce scattered showers and thunderstorms on Tuesday afternoon and evening, some of which could be strong to severe, especially across northern PA. 2) A strong cold front to bring showers and thunderstorms with the potential for severe weather on Wednesday followed by colder temperatures. && .DISCUSSION... KEY MESSAGE 1: Hottest temperatures of the year so far forecast this afternoon along with some scattered storms in south central PA. An expansive deck of fair weather cumulus had developed across the Commonwealth this afternoon with very warm temperature and sticky-but-not-overly-humid dewpoints. Convection has begun to fire in the West Virginia panhandle and will continue to extend north-northeastward this afternoon and evening as temperatures continue to rise under an anomalous upper level ridge. 500 mb heights per the GEFS will rise to near 590mb this afternoon across southeast PA, correlating to standardized anomalies of +2 sigma along the Mid Atlantic Coast through 18z Tuesday. We collaborated with LWX and SPC to paint a MRGL risk for SVR TSRA this afternoon from the Scent Mtns to the West Branch Valley of the Susq. This corridor will be near the eastern edge of somewhat stronger (35-40 kt) swrly mid level winds with MU CAPE reaching near 2000 J/KG. Additionally, the eastern edge of an elevated mixed layer (currently over the Middle Ohio River Valley) will be tracking ENE at 15-20 kts and reach the western edge of the MRGL Risk area around 22-23Z today helping to enhance mid level lapse rates and updraft intensity. The primary hazard with these pulse storms will be the potential for gusty winds associated with the the clearly high- based convection occurring within an inverted-V sounding. Daily record highs could be challenged in some locations. See the Climate section for more details. Manual adjustments were made to lower NBM maxT by a few degrees today due to a known systematic bias correction issue identified during the shoulder seasons. This should also keep max heat indices under 100F, precluding any need for Heat Advisories. Still, heat risk impacts will continue to be monitored given the quick ramp-up in heat and limited acclimation time. Dewpoints over 60F for many will also feel more humid relative the recent cool stretch we've had. ------------------------------------------------------------- KEY MESSAGE 2: More heat & humidity will produce scattered showers and thunderstorms on Tuesday afternoon and evening, some of which could be strong to severe, especially across northern PA. By Tuesday, we'll still be under the influence of the anomalously strong ridge of high pressure, with broad southwesterly flow continuing to pump warmer temperatures and humid conditions into Pennsylvania. Highs on Tuesday should be fairly comparable to today, though afternoon showers/storms in the west could limit how warm it gets there. At the surface, a deepening surface low will lift across the Great Lakes with gradually sinking heights aloft impinging northwest PA. Underneath this sprawling ridge, Pennsylvania will be in a moist and unstable airmass with MUCAPE values expected to reach 1000-1500J/kg. With marginal but sufficient shear, this amount of instability could support a few stronger storms will strong to damaging wind gusts. The SPC upgraded NW PA to a Slight Risk (Level 2 out of 5) of severe weather Tuesday afternoon. The Marginal Risk extends down to about halfway between I-80 and I-76. Low level hodographs do exhibit some spin and an isolated tornado cannot be ruled out in northwest PA closer to the parent surface low pressure system. CAMs disagree on the extent to which convection initiation will occur Tuesday afternoon, but the heat and humidity will provide as much fuel for storm development as we've seen yet this year. Rainfall amounts are not expected to be all that impressive with this system, largely owing to unimpressive/relatively dry moisture profiles with dewpoints in the upper 50s to low 60s. The good news is that these lower dewpoints will keep our heat index values below 100F and mitigate the need for Heat Advisories across the area. Rainfall amounts will be highest west of I-99 and locations farther east may not see much rain at all before Wednesday. -------------------------------------------------------------- KEY MESSAGE 3: A strong cold front to bring showers and thunderstorms with the potential for severe weather on Wednesday followed by colder temperatures. A cold front (accompanied by more widespread and frequent showers/t-storms) brings relief to the relatively short bout of heat and moderate humidity Wednesday into Thursday. High temperatures on Wednesday in northwest PA (behind the front) will be nearly 20 degrees cooler than Monday/Tuesday. The Lower Susquehanna Valley will squeak out another warm day with highs in the upper to 80s to near 90F. Ahead of and along the front, there will be a risk for severe weather again on Wednesday. The magnitude & location of the severe threat will be highly dependent on cold front passage timing and amount of cloud cover in advance of the frontal boundary. A Marginal Risk area covers locations south and east of the I-80/I-99 corridor and highlights locations along and downstream of the cold front between 12PM and 8PM on Wednesday. A few of the hi-res models depict a slower cold front passage. Such a solution would allow for more destabilization ahead of the front and a higher threat for damaging straight line winds. If the front ends up being faster than progged, clouds/rain in the morning could limit instability and lead to an unimpressive gusty shower event. Regardless, this system will feature beneficial rainfall with rainfall amounts generally 0.10-0.25" and locally higher totals possible in thunderstorms. In the wake of the cold front, high pressure will build in for a short time. Temperatures are forecast to cool down back to historical/climo averages for late May for the end of next week. Early indications show the aforementioned cold front stalling out south of the Mason-Dixon line late in the week and lifting back north across PA as a warm front into Memorial Day weekend. The current outlook favors a cooler/wetter stretch through the holiday weekend thanks to that warm front, but there is still a lot of time for the forecast to trend in a more favorable and optimistic direction for the holiday weekend that marks the unofficial start of summer. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... Scattered cumulus clouds have been noted moving over the central Pennsylvania air space. Flight conditions are expected to remain VFR throughout the TAF period outside of a an isolated thundershower this afternoon. Confidence is overall low on thunderstorm development this afternoon. Forcing for storms is weak despite the available energy in the atmosphere. Latest CAM guidance would indicate a narrow window for convective storms to develop after 22Z this afternoon. These storms will be very isolated in nature, and PROB30 groups have been included at airfields that may see one of these storms. Overnight, a shortwave tracking across the Great Lakes may result in a few showers/thundershowers across West-Central PA (mainly KBFD), though flight restrictions appear unlikely with this activity. After 12Z on Tuesday clouds will begin to scatter out again and clear, with wind gusts up to 25kts possible again on Tuesday throughout the afternoon. Outlook... Tue...Mainly VFR. Patchy A.M. fog possible. Isolated P.M. shower or t-storm possible. Wed...Restrictions probable through Wednesday night with widespread showers/storms along CFROPA. Thu...Lingering showers across S PA, restrictions possible. Fri...Lingering showers across S PA, restrictions possible. && .CLIMATE... The following climate sites across central Pennsylvania set new daily high temperature records for May 18th: * A record high temperature of 92 degrees was set in Altoona, breaking the previous record of 91 degrees initially set back in 1962. This record was tied two times previously, back in 1996 and 2017. * A record high temperature of 86 degrees was set in Bradford, breaking the previous record of 85 degrees set back in 1962. ** Note: The high temperature for State College will be reported around 7AM on 5/19. This is due to the State College CO-OP observations running 7AM-7AM. Thus, today's (5/18) high temperature will be reported in tomorrow's (5/19) observation. This record, for reference, is 92 degrees set in 1962. --------------------------------------------- Abnormally warm temperatures will continue on May 19th, thus multiple sites could challenge daily record high temperatures. Daily Maximum High Temperatures for May 19th: * Harrisburg: 95F set in 1962 * Williamsport: 96F in in 1996 * Altoona: 92F set in 1996 * Bradford: 85F set in 1962 * State College: 92F set in 1934, tied in 1996. && .CTP WATCHES/WARNINGS/ADVISORIES... Air Quality Alert until midnight EDT tonight for PAZ057-059- 063-065-066. && $$ WHAT HAS CHANGED...Banghoff KEY MESSAGES...Lambert/Banghoff DISCUSSION...Lambert/Banghoff AVIATION...Bowen/Teare CLIMATE...Beaty  037 FXUS64 KBRO 182245 AFDBRO Area Forecast Discussion National Weather Service Brownsville TX 545 PM CDT Mon May 18 2026 ...New AVIATION... .KEY MESSAGES... Updated at 544 PM CDT Mon May 18 2026 Key Messages: * Heat Risk for today and tomorrow is a mixture of moderate and major. * Strong to severe thunderstorms along with heavy rainfall and localized flooding is possible starting Wednesday through Friday. * A Small Craft Advisory has been extended till 9 AM CDT Tuesday; a High Risk for Rip Currents continues through Tuesday evening as well. && .DISCUSSION... Issued at 1242 PM CDT Mon May 18 2026 While the heat will continue to linger as a potential hazard with high temperatures in the upper 90s to lower triple digits for today and tomorrow. The high temperatures for Wednesday do slightly lower to mostly in the mid 90s as cloud coverage starts to increase, which will be further discussed later on. The heat indices for today and tomorrow do generally float around 108 F. While still below the Heat Advisory criteria, the heat risk for today and tomorrow is moderate (level 2 of 4) and major (level 3 of 4). Thus it will still be important to practice heat safety when possible especially to those that are vulnerable to heat related illnesses. By Wednesday, cloud coverage is expected to increase over the region as a frontal boundary stalls to the north of the region. With the combination of southwesterly flow aloft, southeasterly flow at the surface, and the frontal boundary to the north. The environment will become more favorable for the development of showers and thunderstorms. As of this current forecast the best chances for rain are on Thursday and Friday with rain chances between 60 to 80% during those days. While chances are generally medium (around 50%) for Wednesday and the rest of the forecast period. Currently the Weather Prediction Center does have all of Deep South Texas and the Rio Grande Valley in a Marginal Risk (level 1 of 4) for Excessive Rainfall days 3 through 5, which covers Wednesday morning through Saturday morning. Thus it will be possible to see some flooding due to the rainfall. The Storm Prediction Center also has a Marginal Risk (level 1 of 5) for severe weather for mostly the Upper Valley for Tuesday through Wednesday. However the rest of the region is in a general thunderstorm outlook thus it is possible for showers and thunderstorms to occur all over the area that day. Lastly for the coastal hazards, while the Coastal Flood Statement was allowed to expire early this afternoon, but it is possible that another Coastal Flood Statement might be needed tonight. A High Risk of Rip Currents is in effect through Tuesday evening. && .AVIATION... (00Z TAFS) Issued at 544 PM CDT Mon May 18 2026 Through 00z Wednesday....VFR-MVFR conditions will prevail through the 00z TAF cycle. VFR conditions will be more prevalent during the afternoon-evening hours with MVFR conditions more prevalent during the night-morning hours. Breezy southeast winds will continue through the forecast period with speeds between 10-17 knots and gusts between 20-25 knots or so. && .MARINE... Issued at 1242 PM CDT Mon May 18 2026 Hazardous marine conditions are expected to persist through most of tonight and into early tomorrow morning, thus a Small Craft Advisory remains in effect until 9 AM tomorrow. Even after the Small Craft Advisory does expire tomorrow morning, adverse conditions are still expected for most of the day tomorrow as seas will take more time to come down. Showers and thunderstorms are expected to return to the region by Wednesday and will continue to persist through the forecast period. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 81 94 81 92 / 10 10 20 0 HARLINGEN 79 95 79 93 / 10 0 20 0 MCALLEN 81 97 80 94 / 20 10 30 10 RIO GRANDE CITY 79 98 78 94 / 20 10 40 30 SOUTH PADRE ISLAND 81 86 81 85 / 10 10 20 0 BAYVIEW/PORT ISABEL 81 92 81 90 / 10 0 20 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...High Rip Current Risk through Tuesday evening for TXZ451-454-455. GM...Small Craft Advisory until 9 AM CDT Tuesday for GMZ130-132-135- 150-155-170-175. && $$ SHORT TERM...64 LONG TERM....64 AVIATION...23-Evbuoma  001 FXUS66 KPDT 182243 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 343 PM PDT Mon May 18 2026 .KEY MESSAGES... - Scattered showers and isolated thunderstorms over Wallowa County today - Breezy to locally windy westerly winds through the Cascade gaps today and Tuesday - Warming and mostly dry Tuesday through the week && .DISCUSSION... Daytime heating has led to modest instability (surface-based CAPE of a couple hundred J/kg or less per SPC's RAP-based mesoanalysis and forecast soundings from the 12Z HREF/REFS) this afternoon across the Blues and Washington Cascades. While activity has been isolated elsewhere, scattered rain showers have developed across Wallowa County. Through evening, there is a slight chance (15 percent) of thunder across Wallowa County, with lower (5-10 percent) chances of rain showers and thunder for other parts of the Blues as well as the Washington Cascades. Tuesday through Saturday, warming temperatures and mostly dry conditions are forecast region-wide as an upper-level ridge of high pressure will likely (90-95 percent chance) build into the region from the Pacific and dominate the weather. A couple weak shortwaves passing through northwesterly flow aloft coupled with modest diurnally induced instability (surface-based CAPE of a up to a couple hundred J/kg from forecast soundings) may facilitate some isolated showers for the mountains through Thursday, but PoPs are low (10 percent or less). Breezy to locally windy westerly winds are forecast through the Cascade gaps today and Tuesday, but not anticipating a need for any wind headlines. In yesterday's discussion, mentioned the potential for westerly winds to meet advisory criteria on Thursday. Ensemble guidance has since trended towards a solution that would lead to a wind reversal to mostly light northeasterly (offshore) winds late Wednesday and Thursday as a shortwave digs south across the northern Plains and Rockies, just clipping the edge of our forecast area. Considering there is still some ensemble spread, will place confidence in this solution at medium (60 percent). Considerable uncertainty in the 500-hPa pattern is present in ensemble solutions by the weekend, with roughly 45-50 percent of the variance in solutions explained by timing differences among solutions regarding the arrival of a trough or closed low from the Pacific. The NBM has westerly winds returning to the region by late Friday, persisting through the weekend. Highest chances (10-40 percent) of reaching advisory-level winds have now been pushed back to Saturday and Sunday through wind-prone areas of the lower elevations, primarily the eastern Columbia River Gorge, north-central Oregon, the foothills of the Blue Mountains, and the Kittitas Valley. Of course, the magnitude of winds will be tied to the synoptic pattern, and given the uncertainty (see paragraph above), can't really talk about much confidence in forecast details yet. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... VFR conditions are forecast for the next 24 hours at all sites. Winds will be diurnally and terrain-driven, breezy from late morning through evening. There is a very low (10 percent) chance of rain showers this afternoon at YKM with even lower chances (5 percent or less) elsewhere. && .Preliminary Point Temps/PoPs... PDT 42 72 46 73 / 0 0 0 0 ALW 46 72 49 73 / 0 0 0 0 PSC 44 77 48 79 / 0 0 0 0 YKM 44 76 47 79 / 0 0 0 0 HRI 44 75 48 77 / 0 0 0 0 ELN 41 68 43 73 / 0 0 0 0 RDM 30 72 37 74 / 0 0 0 0 LGD 36 68 40 70 / 0 0 0 0 GCD 34 71 38 74 / 0 0 0 0 DLS 45 74 49 78 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... WA...None. OR...None. && $$ DISCUSSION...86 AVIATION...86  594 FXUS63 KLSX 182254 AFDLSX Area Forecast Discussion...Updated National Weather Service Saint Louis MO 554 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 Theshortwave that was over Arkansas this morning is currently over eastern Missouri with widespread convection ongoing over the St. Louis terminals. The back edge of the storms are approaching from the west, with a temporary end to the thunderstorms expected at all terminals by 8 PM. Another line of showers and thunderstorms (currently in central Kansas) is then forecast to progress into central Missouri early Tuesday morning. Now that the line has formed, have gone ahead and updated the TAFs with the latest thinking of arrival. KUIN: High confidence that thunderstorms will make it Tuesday morning between 6 and 9z. KCOU/ KJEF: High confidence that showers will make it and moderate confidence that thunder will be observed. Arrival time between 6 and 9z. KSTL/ KSUS/ KCPS: Moderate confidence that showers will make it and low confidence that thunder will be observed. Arrival time between 7 and 10z. By late morning, showers from the decaying line that originated from Kansas will be mostly dissipated. A cold front will then cross KUIN with cigs falling to MVFR/ borderline IFR. The front will then cross or be just north of KCOU and KJEF. On the cool side of the boundary expect sub- VFR cigs. For the St. Louis terminals, the thinking is the cold front will hold northwest of the area until late Tuesday afternoon. Out ahead of the cold front, another round of afternoon showers and thunderstorms will occur. The lack of confidence is on the location of the cold front and the aforementioned convection. 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  824 FXUS64 KMRX 182259 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 659 PM EDT Mon May 18 2026 ...New AVIATION... .KEY MESSAGES... Updated at 224 PM EDT Mon May 18 2026 - Very warm temperatures for Tuesday with highs 10 to 15 degrees above nromal. - Increasing chances for showers and storms return Wednesday. Scattered showers and thunderstorms are expected each day from Thursday through the weekend especially across the higher elevations. && .DISCUSSION... Issued at 224 PM EDT Mon May 18 2026 Main weather feature through Tuesday night will remain an upper ridge over the southeast United States into the southern Appalachians. Main impact will be mostly dry and unseasonably very warm temperatures. Highs will be 10 to 15 degrees above normal. Near record highs anticipated. For Wednesday, ensemble cluster analysis shows a short-wave trough moved east of Great Lakes and upper Ohio valley. This wave will weaken the upper ridge over the region and allow a frontal boundary to approach the area. Lower heights and better PWs will allow for increasing chances of showers and thunderstorms especially over the Plateau counties. Instability with remain marginal with CAPES of 1000-1500, mid-level lapse rates of 6 degrees or less with little to no shear. At this time severe storms are not anticipated. For Thursday, frontal boundary remains near the region with PWs of 1.5-1.7 inches so moisture returns over the area. Depending where frontal resides (GFS suggests across northeast Tennessee and southwest Virginia) that is where the highest chances of convection will be. Instability and shear remain limited with little to no severe threat, but fairly good coverage of showers and storms with much needed rainfall. QPF for Wednesday through Thursday will range from 0.10 to 0.50 inch. For Friday, frontal boundary lifts north as an upper trough/jet moves northeast into the mid-west and Ohio valley producing pressure falls there. The increase in southerly boundary jet will pull frontal boundary north. Plenty of moisture and instability remains so scattered showers and thunderstorms developing into the afternoon especially across the terrain features. For Saturday through Monday, the southern Appalachians will remain with plenty of moisture and afternoon instability with an upper trough across the southern Plains. This upper trough will slowly move toward the Tennessee valley. Ensembles and deterministic models show better instability with possible short-waves ejecting out the trough across the region. There is a greater threat of stronger afternoon storms during this period. && .AVIATION... (00Z TAFS) Issued at 656 PM EDT Mon May 18 2026 VFR conditions are expected for the period all sites. Winds will become light overnight, then south and southwest around 10kts or less during the day Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 68 89 68 88 / 0 10 10 70 Knoxville McGhee Tyson Airport, TN 67 90 68 88 / 0 0 0 30 Oak Ridge, TN 66 88 65 86 / 0 0 10 60 Tri Cities Airport, TN 62 89 63 87 / 0 0 0 40 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...DH AVIATION...99  850 FXUS62 KRAH 182259 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 700 PM EDT Mon May 18 2026 .WHAT HAS CHANGED... * No major changes. && .KEY MESSAGES... As of 215 PM Monday... 1) Hot and mainly dry through Wednesday. 2) Rain chances return mid-week, highest on Thursday, and linger through the weekend. Low confidence in high temps Thursday and especially Friday. && .DISCUSSION... As of 215 PM Monday... KEY MESSAGE 1... Hot and mainly dry through Wednesday. An unseasonably strong mid/low-level anticyclone (700mb heights well exceeding the daily max at GSO, MHX, CHS, and RNK), and strong cap at the base of steep mid-level lapse rates (associated with a modified EML and persistent subsidence) sampled in the 12z RAOB data over Carolinas and portion of the Southeast, will keep conditions capped and void of precipitation amidst seasonably moist deep-layer moisture in place. Warm temperatures though the mid/low-lvls will exceed the 99th percentile through at least Wednesday and support several days of hot conditions at the surface when temperatures should regularly eclipse 90 degrees by mid-afternoon. Given central NC's position within the described weather pattern above, there are minimal failure modes and reasonably high confidence in the forecast high temperatures through Wed. Minimal mixing out of dew points have been observed over the past couple days over the Carolinas, and adjusted heat indices will remain below triple-digits, but still reach into the mid-90s in most locations. This kind of early-season heat can still be unexpectedly dangerous, as people have not yet become acclimated to the hot weather. The daily experimental Heat Risk is expected to peak at Moderate (level 2 of 4) today through Wed, but may reach Major (level 3 out of 4) in urban areas around the RTP. This kind of heat is quite unusual for this time of year and has historically led to high levels of heat illness, with sensitive individuals and those without adequate cooling particularly vulnerable. And with just a modest breeze and lots of sunshine each day, the WBGT index will also be elevated, so spending time in the shade is encouraged, especially for those working or exercising outdoors. KEY MESSAGE 2... Rain chances return mid-week, highest on Thursday, and linger through the weekend. Low confidence in high temps Thursday and especially Friday. The mid-level ridge will weaken and shift out of the region Wed/Wed night as a s/w tracks ewd across the Northeast US/mid-Atlantic. The sub-tropical ridge may once again strengthen and lift newd across the region Thu night through Sat, with several s/w disturbances tracking across the Plains and MS Valley. At the surface, a pre- frontal trough will develop over the area on Wed, with Bermuda high pressure to the east and a cold front approaching from the north, remaining in place until the cold front slides southward across central NC on Thu. A brief CAD may set up Thu night into Fri as high pressure tracking across the Northeast US ridges swd into the area. Expect the front to lift nwd back across the area Fri night/Sat, however the spread in available guidance increases beyond Fri and details remain uncertain thereafter. Precipitation: The northern and northwest Piedmont could see showers/isolated storms as early as Wed evening, however the better chances will come Thu along and ahead of the backdoor cold front as it moves into and across the area. In the wake of the front, warm air advecting in above the cooler, stable boundary layer could result in some light rain Thu night into Fri over central NC. Assuming the wedge erodes Fri night into Sat and a warm front lifts nwd across the area, there will be the chance for additional diurnally driven convection over the weekend, especially along differential heating boundaries. Temperatures: Highs Thu will be impacted by the timing of the front and the convection ahead/along it. For now, expect highs ranging from around 80 degrees north to low 90s south. There is a large bust potential wrt highs on Fri given the potential for CAD to briefly set up and possible continued rain into it. For now have highs ranging from around 70 degrees NW to low/mid 80s south, but with below average confidence. Lows Thu and Fri nights expected to range from mid 50s north to mid 60s south. Generally expect temperatures to moderate back to near/slightly above normal over the weekend. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... As of 700 PM Monday... Prevailing VFR conditions are expected through the 24 hr TAF period 00Z/19 May. Outlook: There is a chance of low stratus both Wednesday and Thursday mornings. Then scattered to numerous showers and a few thunderstorms are expected Thursday surrounding a backdoor cold frontal passage and breezy NE winds. Brief classical CAD will likely bring sub-VFR cigs to all terminals behind the fropa that will likely persist into Fri, especially in the typical CAD regime at INT/GSO and potentially RDU. There is a chance of showers/storms through the weekend with daily MVFR to nightly IFR conditions possible. && .CLIMATE... Record High Temperatures: May 18: KGSO: 95/1911 KRDU: 95/1906 KFAY: 96/1911 May 19: KGSO: 96/1911 KRDU: 95/1962 KFAY: 96/2022 May 20: KGSO: 95/1917 KRDU: 96/2022 KFAY: 99/2022 Record High Minimum Temperatures: May 18: KGSO: 70/2015 KRDU: 72/1896 KFAY: 71/2018 May 19: KGSO: 68/2018 KRDU: 70/2022 KFAY: 75/1930 May 20: KGSO: 68/2022 KRDU: 69/2019 KFAY: 71/2022 May 21: KGSO: 67/2022 KRDU: 71/1898 KFAY: 71/2025 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...AS/10 AVIATION...Badgett/AS CLIMATE...RAH