342 FXUS61 KCTP 221501 AFDCTP Area Forecast Discussion National Weather Service State College PA 1101 AM EDT Sat Aug 22 2026 .WHAT HAS CHANGED... * SPC has continued to extend/expand the risk of severe thunderstorms to the east another tier or more of counties for both the SLGT and MRGL areas. * Updated near term sky/temps/PoPs to match current trends. && .KEY MESSAGES... 1) Upper level low pressure swinging SE from the upper Glakes to southern Ontario will lead to high temps trending cooler by a few to several degrees each day through Monday along with periods of showers and isolated to scattered gusty thunderstorms. && .DISCUSSION... KEY MESSAGE 1: Upper level low pressure swinging SE from the upper Glakes to southern Ontario will lead to high temps trending cooler by a few to several degrees each day through Monday along with periods of showers and isolated to scattered gusty thunderstorms. 11 AM Update... The fog has burned off, but cu has started to expand a bit across the S. Temps pleasant and dewpoints climbing with M60s in the Lower Susq. TSRA over Erie are sliding N of the CWA, but certainly a bit of lift remains and could flare up. Previous... Significant amplification of a longwave trough will occur over the next several days across the Glakes, Mid Atlantic region and Central Appalachian with 500 mb height falls of 60-100 meters and mean 850-700 mb layer temps of around 6 deg C from this evening to Monday morning. Abundant sunshine expected across the CWA North and West of the Lower Susq Valley with max temps this afternoon generally between 75-80F. The initial lead shortwave and right entrance region of a 65 kt upper level jet trailing a zone of very sharp upper diffluence over the western 1/3 of PA late today/early tonight will support development of scattered strong to severe TSRA across the western 1/3 to 1/2 of our CWA with the likely evolution/upscale growth of multicell clusters into a bkn line of TSRA with its axis near the RT 219 corridor between 00Z and 03Z Sunday where 0-1KM EHI will be in the 1-1.5 M2/S2 range and 0-3 KM Bulk shear will be average 20-25 KTS with some pockets just above 30 kts across the NW Mtns near KBFD at 03Z Sunday. HREF MU CAPE Values do drop off fairly quickly from their late afternoon/early evening peak of 1200-1500 J/KG across western PA, and the severe threat will be diminished by 02z across the Mtns of Western PA. The eastern half of PA will get the gradually weakening convection later this evening/overnight. For Sunday, the best larger scale/deep layer cooling aloft will occur across the eastern half of the state and that will be the focus for the SVR threat. MU CAPE will be lower by around 500 J/KG but deep layer swrly shear will be 35-40 kts across our eastern CWA. Therefore, SPC's MRGL risk covers the better threat for gusty winds with the storms across the eastern half of PA on Sunday with some isolated occurrences of pea to marble size hail in the taller storms Sunday. The cyclonic flow may keep showers downwind of Lake Erie into Monday. Daytime highs will be near to slightly below the historical average for late August, making it feel more like mid September especially Sunday into Monday. SPC trimmed the MRGL back a bit to the west on Saturday, which should feature early day clouds and a few showers spreading from SE to NW during the day. Drier/less humid conditions are likely to prevail during the first half of next week. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... Highly variable cigs and vsbys for the mid to late morning in radiational/valley fog regime with vsbys ranging from 1/4SM to 2SM+ in just a few miles. In any event, all TAF sites in Central and Western PA will be MVFR or better by 14Z today, while KLNS may stay MVFR w/respect to CIGS for the entire daylight hours today. While VFR in a SCT/BKN stratocu cloud deck will be the prevailing conditions today, some isolated showers are possible in the afternoon. Chances for this are highest at MDT and LNS with spotty morning activity possible as well. This activity may lead to bounces between VFR and MVFR throughout the day tomorrow in the southeast, with greater restrictions more likely at LNS. This showery activity will be ahead of a cluster of storms moving through in the evening/early night along and ahead of a cold front. Have updated PROB30s for -TSRA to reflect most confident timing at the current moment. HREF ensemble and NBM trending later in storm timing in their most recent runs. Should a strong core cross paths with an airfield, brief IFR restrictions are possible. Outlook... Sun...Restrictions possible, mainly NW in SHRA. Improvement elsewhere. Mon-Wed...Patchy morning fog, otherwise mainly VFR conditions return early next week. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ WHAT HAS CHANGED...Dangelo KEY MESSAGES...Dangelo/Steinbugl/Banghoff DISCUSSION...Lambert/Dangelo/Steinbugl AVIATION...Lambert/Lambrech  516 FXUS65 KMSO 221529 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 929 AM MDT Sat Aug 22 2026 .UPDATE...Red Flag Warning issued across the West Lolo and Kootenai National Forests 5 PM today through 6 AM Sunday for lightning and outflow winds. Red Flag Warning issued for Deerlodge/West Beaverhead from 1 PM to 8 PM Sunday due to windy and dry conditions. && .PREV DISCUSSION... /ISSUED 400 AM MDT Sat Aug 22 2026/ DISCUSSION... KEY MESSAGES: - Strong to severe thunderstorms today through the afternoon and evening. - Cold front Sunday brings cooler temperatures but strong westerly winds and very dry air. - Ridge rebuilds into next week. Light rain showers this morning depicted on radar continue to expand northward. The main convective event develops this afternoon around and after 2pm MDT. Storms will generally track from southwest to northeast. A marginal risk for severe thunderstorms covers the region, with damaging wind gusts toward 60 mph remaining the primary hazard of concern alongside small hail and frequent lightning. High precipitable water values entering the region under monsoonal flow will support brief heavy rainfall under stronger showers and storms bringing localized threats for excessive runoff and flash flooding over urban areas and within steep terrain and burn scars. Lingering showers and isolated convection will persist through the overnight as the strong to severe thunderstorm threat begins to diminish. A cold front crossed the Northern Rockies late tonight into Sunday, ushering in a brief temperature respite with daytime highs dropping 10 to 15 degrees to near seasonal averages. Deep boundary-layer mixing behind the front will drive strong westerly winds within the very dry post-frontal airmass. Elevated to critical fire weather conditions are anticipated across the region on Sunday. High pressure rebuilds early next week marking the return of hot daytime temperatures and generally dry conditions. Near-daily afternoon showers and thunderstorms will remain possible in southwestern Montana and Lemhi County. Ensemble cluster analysis shows moderately high confidence (70%) in a progressive pattern returning to the region by mid-to-late next week, though details about timing and strength of any inbound troughing remain uncertain at this time. AVIATION...Morning light rain showers will yield to strong afternoon and evening thunderstorms tracking southwest to northeast between 22/2000Z and 23/0400Z. Localized direct impacts from convection will bring erratic outflow wind gusts of 30 to 50 knots, small hail, brief heavy rainfall causing localized MVFR/IFR visibility, along with LLWS and turbulence near storm cores. Strong westerly winds develop post-frontally on Sunday on an otherwise dry and less-problematic day for aviation. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Red Flag Warning from 5 PM this afternoon to 6 AM MDT Sunday for Kootenai...West Lolo. Red Flag Warning from 1 PM to 8 PM MDT Sunday for Deerlodge/West Beaverhead. ID...None. && $$  985 FXUS63 KABR 221541 AAB AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 1041 AM CDT Sat Aug 22 2026 .KEY MESSAGES... - Mainly dry conditions will continue through next Wednesday with temperatures around average for this time of year. - There is a 30-60% chance for showers and thunderstorms during the day Sunday into early Sunday evening over central SD, expanding to northeastern SD/west central MN Sunday night while increasing to a 50-70% chance. - There is a Marginal Risk (level 1 out of 5) of severe weather Sunday night over much of central to northeastern SD. Brief heavy rain, lighting, and strong winds to around 60 mph will be the main concern. && .UPDATE... Issued at 1040 AM CDT Sat Aug 22 2026 The current forecast looks good overall. No major changes planned at this time. UPDATE Issued at 616 AM CDT Sat Aug 22 2026 Update for 12Z Aviation Discussion below. && .DISCUSSION... Issued at 113 AM CDT Sat Aug 22 2026 As of 1 AM CDT, temperatures around the area are in the 60s with winds out of the north to northeast at generally less than 10 mph. Today will be pretty similar to the last few days with some showers and maybe some weak thunderstorms across central SD after midnight and into Sunday. These storms are expected to continue through the day Sunday, with a marginal risk (level 1 out of 5) for severe storms. This outlook may be upgraded in future forecasts. The main threats look to be hail and wind. The NAM Nest in particular looks to have a bit of a bowing formation to the storms later in the evening which could produce some stronger winds. The environment for those storms will be rather moist. PWAT values are again in the 99th to 99.5th NAEFS percentile and 1.5" over central SD. This could lead to some heavy rainfall during storms. Models are starting to increase MLCAPE with generally 1100-1200 J/kg. Lapse rates have actually come down a little in deterministic models. Looking at Monday, PWAT isn't as impressive but MLCAPE values are between 1200 and 1500 J/kg with lapse rates between 7 and 7.5 C/km. Temperatures throughout the period will remain around average with highs in the 80s. Not too much in the way of smoke today, but there is a narrow band of some increased concentrations over the Missouri River valley. This would just bring a slight haze to the skies, nothing is expected to reach the surface. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 616 AM CDT Sat Aug 22 2026 Terminals KABR,KATY,KPIR,KMBG VFR conditions will prevail during the period, as high pressure gradually departs today and leads to increasing high clouds this evening. Tried to show a little decrease in CIGS in central SD during the overnight hours and added in a PROB30 for showers potentially nearing KPIR during the last few hours of the forecast period. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...17 DISCUSSION...13 AVIATION...SRF