974 FXUS63 KBIS 231502 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 1002 AM CDT Sun Aug 23 2026 .KEY MESSAGES... - Isolated to scattered severe thunderstorms are possible across western and south central North Dakota this afternoon and evening. Potential hazards include hail up to the size of ping pong balls, damaging winds up to 70 mph, and torrential downpours. - Conditional risk for isolated severe thunderstorms in central and eastern North Dakota Monday afternoon and evening. Potential hazards include large hail up to 2 inches in diameter and damaging winds up to 70 mph. - Temperatures generally favored to remain near average through next week. - Near-critical fire weather conditions could develop in parts of western North Dakota on Monday, and the far southwest on Tuesday. && .UPDATE... Issued at 1000 AM CDT Sun Aug 23 2026 Scattered convection has developed near the Montana/North Dakota border and continues to lift northeast. Instability is rather weak in this area, so do not believe it poses a severe threat as it continues to work into northwest North Dakota, but have increased precipitation chances to address the showers/storms. UPDATE Issued at 644 AM CDT Sun Aug 23 2026 The forecast for today remains on track. Current conditions and trends were blended in for this update. && .DISCUSSION... Issued at 422 AM CDT Sun Aug 23 2026 An upper level ridge axis extends from the Texas Panhandle through western North Dakota early this morning, with a shortwave ejecting off the Northern Rockies preceding a deeper closed low over western Washington. The shortwave will be the main focus for showers and thunderstorms developing in western and central North Dakota later this morning through this evening. A handful of models bring some weaker elevated convection into southwest North Dakota by mid morning, but there is better consensus for an increase in both coverage and intensity beginning in northwest North Dakota early this afternoon and spreading south and eastward through the late afternoon and evening hours. Showers and storms will develop over a boundary layer with a southerly, moisture-rich return flow, although there is some question whether an MCS over southwest South Dakota and northern Nebraska early this morning could impede moisture transport to some extent. That uncertainty aside, diurnal heating should contribute to CAPE increasing as high as 2000 J/kg with deep layer shear forecast to increase from 30 kts in the afternoon to 40 kts in the evening. There are some factors that could dampen the intensity of convection, including mid level lapse rates less than 6 C/km and a capping inversion that boundary layer mixing and cooling aloft from height falls may not be able to fully erode. Nevertheless, recent CAMs have certainly honed in on an outcome that includes a few severe thunderstorms over parts of western and central North Dakota from mid afternoon through this evening. A lack of a well-defined surface boundary and a mixture of shear and deep layer wind vector orientation to the dewpoint/CAPE gradient would seemingly point toward a multicell/cluster storm mode, which fits with CAMs' reflectivity simulations. Confidence in sustained supercellular structure is low, so have limited our most likely maximum hail size forecast to ping pong balls for now. If upscale growth can lead to more organized convection, damaging winds up to 70 mph could emerge as the dominant severe hazard, especially in the evening when 0-3 km shear could increase to 35 kts. Despite low LCLs and 0-1 km shear greater than 10 kts, model hodographs do not appear to be supportive of tornadogenesis. While instantaneous rainfall rates could be quite high with these storms, their forward propagation should limit the risk for localized flooding, with urban areas being a possible exception. Back to the west, the deeper closed low is forecast to eject off the Canadian Rockies this evening. Lee cyclogenesis is already underway from Alberta through central Montana, but the lee trough/cold front is not forecast to reach western North Dakota until later tonight. Models have shown mixed signals on whether strong to severe convection associated with the trough in central/eastern Montana this afternoon and evening will survive into western North Dakota later tonight. More recent guidance has trended to a lower probability of convective maintenance, which may be due in part to the increased probabilities of thunderstorms in North Dakota stabilizing the air mass in between the two convective systems. MUCAPE is actually projected to remain as high as 2000 J/kg through the night in western North Dakota, but model soundings reveal the most-unstable layer to be highly-capped. Depending on the timing of decaying convection, there could be some higher wind gusts sneaking across the Montana border around midnight. A conditional threat for severe storms continues in central and eastern North Dakota on Monday, but confidence in convective initiation is quite low. Even though several forcing mechanisms are forecast to be present, including mid level height falls/ DCVA, low level warm air convergence, and surface convergence along the frontal boundary attendant to the Canadian low, there may not be enough of an alignment of these features to ensure deep moist convection initiates, and there are a number of possible scenarios and combinations thereof being displayed by the suite of CAMs. First, there is potential for elevated morning convection moving across northern North Dakota ahead of the surface front in an area where stronger warm air advection on the mesoscale could overlap with stronger height falls as the Canadian upper low spins over southern Saskatchewan. This may or may not play a role in afternoon convection if it occurs. A capping inversion will almost certainly delay surface-based convection until late afternoon and early evening. Then it becomes a question of whether strong enough forcing will come into alignment for sustained deep moist convection. Despite the low probabilities for convective initiation and coverage, the threat ceiling may be higher than today, with CAPE around 2000-2500 J/kg and deep layer shear closer to 40-50 kts. Unlike today, there is a clear favoring of a discrete storm mode with shear and deep layer wind vectors perpendicular to the surface boundary. Model hodographs are long and mostly straight, but with enough curvature to support splitting supercells. The most likely maximum hail size forecast for Monday has therefore been increased to 2 inches in diameter, with the maximum wind gust forecast remaining at 70 mph on account of forecast DCAPE around 1000-1500 J/kg. Similar to today, the tornado risk on Monday appears to be low on account of modeled hodograph structure, despite low LCLs and modest low level shear. In non-convective forecast news, today will be seasonably warm and humid with highs mostly in the 80s and dewpoints rising into the mid 50s to mid 60s. It will also be a bit breezy with southeast winds around 15-20 mph. Monday is favored to be the warmest day of the upcoming week for most areas, with widespread highs around 85 to 90. The post-frontal air mass in western North Dakota will become very dry and could feature gusty northwest winds Monday afternoon, which may lead to near- critical fire weather conditions. The southern Canadian low, which will become nearly-stacked Monday night, is forecast to dive southeastward into the Red River Valley on Tuesday. This brings slightly cooler daytime temperatures and stronger northwest winds into the forecast as the surface pressure gradient gets squeezed between the low and high pressure building over Alberta and Saskatchewan. RH could be low enough in the far southwest for another afternoon of near-critical fire weather conditions on Tuesday. The NBM has also increased PoPs for diurnally-driven showers in the northwest cyclonic flow regime Tuesday afternoon, just in the Turtle Mountains area for now but could see that expanding with future forecast updates. The downstream low continues a southeastward trajectory toward the Great Lakes on Wednesday as surface ridging slides into the Northern Plains and the upper level ridge begins to reamplify over the Rockies. A deeper trough digging into the Pacific Northwest on Thursday could push the upper ridge back into the Northern Plains by the end of the week, with ensemble spread on the synoptic pattern increasing thereafter. Ensemble clusters now tend to favor more of a quasi-zonal flow pattern heading into next weekend, which is evident in deterministic guidance. But there is still some support for yet another reemergence of the upper level ridge somewhere between the Rockies and Great Plains. The potential quasi-zonal flow is reflected in the NBM returning daily low to medium shower and thunderstorm chances to the forecast from Friday onward. The temperature outlook for mid to late next week remains close to average, with highs mostly in the upper 70s to mid 80s and lows mostly in the 50s. && .AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 644 AM CDT Sun Aug 23 2026 Chances for showers and thunderstorms will increase from west to east this morning through this evening. A few storms could be severe, particularly in southwest and south central North Dakota from mid afternoon through early evening. If a storm moves over a terminal, IFR visibility and strong wind gusts can be expected, with large hail and a brief MVFR ceiling possible. A few showers and storms could linger into the overnight hours or re-enter western North Dakota late tonight. Outside of showers and storms, VFR conditions and south to southeast winds around 10-20 kts are expected through the forecast period. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...JJS DISCUSSION...Hollan AVIATION...Hollan  224 FXUS64 KHUN 231508 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 1008 AM CDT Sun Aug 23 2026 ...New NEAR TERM, SHORT TERM... .KEY MESSAGES... Updated at 1008 AM CDT Sun Aug 23 2026 - There are low to medium chances of thunderstorms for much of next week. However, timing and impact confidence remains low at this time. && .NEAR TERM... (Rest of Today and Tonight) Issued at 1008 AM CDT Sun Aug 23 2026 Nice start to this morning with current temps in the 70s and sunny skies. The weak cold front will continue pushing southward across the state, keeping us in a drier airmass today. With sfc high pressure pushing into the region from the Midwest, and northwesterly flow aloft, we will see dry conditions under mainly sunny skies. Daytime highs will be seasonable in the upper 80s to lower 90s. Tonight will be really nice as temps fall into the low to mid 60s under partly cloudy skies. && .SHORT TERM... (Monday through Wednesday) Issued at 1008 AM CDT Sun Aug 23 2026 We will start out the week with an upper level low centered in Quebec, a ridge centered in the southern Rockies but amplified up into the Northern Plains and another upper level low in Saskatchewan. Sfc high pressure will continue to push southeastward into the region and keep an MCS dropping out of the Central Plains on Monday to our west. The TN Valley will have a much needed break from the heat and humidity on Monday as daytime highs reach the upper 80s and dewpoints only in the 50s-60s! On Tuesday, a sfc low in the Southern Plains will help return moisture to the region and lift a warm front northward through the day. Could see a few showers/storms return to the far west portion of the CWA on Tuesday otherwise it will be moreso Tuesday night for everyone. Still stuck in this northwesterly flow pattern, a disturbance will slide into the TN Valley on Wednesday, increasing POPs from low chances (20-40%) during the day to to medium chances (50-60%) by Wednesday night. Daytime highs will be in the upper 80s to lower 90s on both Tuesday and Wednesday. && .LONG TERM... (Tuesday night through Saturday) Issued at 641 PM CDT Sat Aug 22 2026 We will continue to be in a northwest flow regime aloft for most of the long term period. However, by Saturday, this pattern begins to break down as the upper trough to the north/northeast flattens and the upper ridge over the Desert Southwest flattens as well and pushes farther east into the ArkLaTex. A lingering surface boundary will also persist over the Southeast into Thursday before what looks like a reinforcing cold front swings through. By late week and into the first part of next weekend high pressure builds over the Appalachians and Ohio Valley. Overall, highs in the upper 80s to lower 90s with lows in the mid 60s to lower 70s will be common through the period. In addition, the above pattern will lead to daily chances of showers and storms from Tuesday through Thursday at least. Expecting lower chances come Friday/Saturday. The best chances look to be during the afternoon and evening hours, during peak heating when storms can take advantage of the greater thermodynamics in place. Ample instability in addition to bulk shear between 20-30 knots, 0-3km lapse rates between 7-8 deg C/km, along with DCAPE around or above 1000 J/kg, will warrant us keeping an eye on the forecast for at least strong to severe downburst potential Wednesday and Thursday. As has been the case recently, the main hazards are likely to be damaging winds, frequent lightning, and perhaps some hail (but freezing levels may be too high). As for heavy rain and flooding concerns, this will need to be monitored as well, since most PWATS are generally between 1.7-2.0 inches Tuesday through Thursday. These values are between the 75th and 90th percentiles when compared to BMX Sounding Climatology, which means that showers and storms will be efficient rainfall producers. Stay weather aware especially if you work outside or have outdoor activities and check back for forecast updates! && .AVIATION... (12Z TAFS) Issued at 633 AM CDT Sun Aug 23 2026 There have been no major changes to previous aviation forecast reasoning, as mid-level clouds should rapidly disperse after 12Z, with only a few fair-weather Cu and few Ci expected during the day. The coverage of high-lvl clouds in NW flow aloft will begin to increase this evening, perhaps becoming overcast and capable of generating some virga or lgt SHRA (especially across northwest AL) by the end of the TAF period. Sfc winds will range from 340-020 at 5-10 kts today, but should veer to NE and diminish after sunset this evening. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...JMS SHORT TERM....JMS LONG TERM....17 AVIATION...70  966 FXUS65 KBYZ 231523 AFDBYZ Area Forecast Discussion...Updated National Weather Service Billings MT 923 AM MDT Sun Aug 23 2026 .KEY MESSAGES... - Showers and thunderstorms possible today. A few storms could be strong to severe, with strong wind gusts 55-65 mph the main threat. Localized heavy rainfall is also possible. - Drier with seasonal temps next week with just an occasional chance of precipitation. && .UPDATE... Showers over northeastern areas are slowly exiting off to the east this morning as remaining energy from last nights wave slides into the Dakotas. Still expecting another round of showers and thunderstorms this afternoon and evening, some of them strong to severe. Have updated PoPs, weather and wind to latest observations and trends this morning. STP && .DISCUSSION... Through Saturday... Upper level troughing moving over the ridge will be the dominant factor in the weather over the next couple of days. Today will see 500-1000 J/kg of CAPE, 30-40kts of 0-6KM shear, and steep lapse rates create a favorable environment for thunderstorm development. The Storm Prediction Center has issued a Risk Level 2 of 5 for severe storms. The main threat with these storms is the potential for wind gusts in excess of 70 mph and hail greater than 1 inch. Thunderstorm chances (20-40%) increase along the western foothills around 12 PM and move east throughout the afternoon and evening. Areas west of Billings could see a period of elevated fire weather concerns on Sunday as pre-frontal conditions bring westerly wind gusts of 15-30 mph, with humidity down near 20 percent. A low pressure system moving through southern Canada Monday will bring a cold front through the region decreasing temperatures from the low to mid 90s F on Sunday to the 80s F Monday. Drier air is expected to move in behind the cold front with minimum relative humidity values expected to be in the teens to low twenties. Breezy winds of 20-30 kts are expected along the western foothills and from Northern Rosebud County southeast to Carter County. This will lead to localized areas of elevated fire concern. Cooler conditions in the 80s F continue Tuesday. Upper level troughing begins to move off to the east Tuesday bringing high confidence in upper level ridging returning. This upper level ridging is expected to interact with an upper level trough over the Pacific Northwest. At this time, models are in agreement that the upper level ridge will win keeping warmer temperatures and drier conditions over our region, and cooler conditions to the west. Upper level high pressure centered over the southwestern US is expected to bring in monsoonal high based moisture bringing daily 10-40% chances for showers and thunderstorms Tuesday through the weekend. Temperatures will continue to be slightly above average in the high 80s and low 90s F Wednesday through Saturday. Torgerson .AVIATION... Another round of showers and thunderstorms will develop over the Beartooth/Absaroka mountains around 19Z and spread east through the region into the evening. Strong wind gusts up to 50kts are the main threat from this activity, particularly at KLVM and KBIL from 22Z to 02Z, and at KMLS between 02Z and 05Z. Wildfire smoke may affect slant range visibility at times. BT && .PRELIMINARY POINT TEMP/POPS... Tdy Mon Tue Wed Thu Fri Sat ------------------------------------------------------- BIL 095 062/088 060/085 061/090 063/093 062/091 062/089 3/T 30/U 00/U 00/B 21/B 20/B 11/B LVM 089 050/086 049/085 051/088 052/089 051/087 051/086 6/T 10/U 01/U 11/B 41/B 31/U 22/W HDN 097 059/088 055/087 056/092 060/094 059/092 058/090 3/T 30/U 00/U 00/B 11/B 20/B 11/B MLS 096 064/087 057/084 056/087 060/093 062/091 061/090 1/B 20/U 00/U 00/U 11/B 21/B 21/U 4BQ 095 065/087 058/085 057/088 061/092 062/091 061/090 2/T 20/U 00/U 00/U 11/B 21/B 21/U BHK 093 059/088 053/085 050/086 053/090 056/090 055/090 3/T 20/U 00/U 00/U 01/B 23/T 22/W SHR 092 057/086 053/084 052/087 055/090 055/089 055/088 3/T 30/B 02/T 12/T 11/B 11/B 11/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings