


Area Forecast Discussion
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
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903 FXUS63 KBIS 090837 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 337 AM CDT Wed Jul 9 2025 .KEY MESSAGES... - Isolated to scattered severe thunderstorms are possible late this afternoon and evening, and again Thursday afternoon into the night. - Hot and humid conditions are expected today, with widespread high temperatures in the 90s. - Temperatures will cool down to the 70s to end the work week, before warming back up again for the weekend. && .DISCUSSION... Issued at 337 AM CDT Wed Jul 9 2025 This morning, a stout upper high was placed over the Desert Southwest, with northwest flow across the Dakotas on the northeast side of this feature and upstream of troughing over the Great Lakes. Further upstream, a closed low and attendant trough are moving onto the Pac NW coast, with a secondary wave in northern British Columbia. At the surface, high pressure was drifting off to our east, while a low centered in the southern Canadian Prairies had a warm front and surface trough extending into central Montana. It will be quite hot and humid today, with highs in the upper 80s to upper 90s, and likely seeing a few locations hit 100 F across western North Dakota where humidity is lower and it is closer to the low-level thermal ridge impinging on the region. Apparent temperatures are getting close to Heat Advisory criteria (100 degrees F), although for a relatively limited area across central North Dakota where there is the most favorable overlap between air temperatures and dew points. Looking upstream across the Central Plains, we aren`t seeing dew points exceeding 70 F, so thinking NBM dew points are reasonable. Besides the heat and humidity, main focus of today is potential for isolated to scattered severe thunderstorms across southwest and central North Dakota. As the warm front moves across the state today, deterministic guidance is advertising a weak impulse moving through flow that turns mostly zonal by this evening. Although there have been some concerns of capping with such warm temperatures in the lower levels, most high-resolution guidance has been consistent in developing convection somewhere across southwest and into south central North Dakota, depending on where the embedded impulse ends up tracking, late this afternoon. As previous discussions have noted, the environment is characterized by extreme instability but quite marginal shear, which will likely limit the upper extent of potential hazards with any thunderstorms that develop. A likely scenario is that there is explosive initial development where large hail is possible, and a tornado can`t be ruled out, especially with any initial storms along the boundary. The lack of shear will limit the lifespan of any storms, with severe gusts possible as the storms collapse, with somewhat inverted V soundings due to hot surface temperatures, and DCAPE in excess of 1500 J/kg. There are some hints of an eventual cluster/upscale growth that would also favor a wind threat, with current CAMs highlighting this potential across the James River Valley and into eastern North Dakota. Best timing window is 3 to 11 PM CDT, starting in the southwest and ending east. We are also carrying some low POPs across the west late tonight into Thursday morning, with another weak impulse moving through, but with limited instability thinking this will just be showers and a few rumbles of thunder. Lows tonight will be in the upper 50s to mid 60s. As the upper trough base approaches from the Canadian Prairies on Thursday, a trailing cold front will approach from the northwest. Some capping from warm 850mb temperatures will likely keep convection at bay initially, although the approaching wave and attendant cold front will provide more robust synoptic forcing compared to today. It`s another case of very high instability in the warm sector, but bulk shear is forecast to be just as low, if not slightly lower, than today, especially in the area of highest buoyancy. Shear starts to increase as the front comes in but there doesn`t seem to be much favorable overlap, although the one area that could potentially see higher shear with sufficient instability would be the north central. Some of the higher- res guidance isn`t as set on convective development compared to global models, but thinking there is still potential for isolated to scattered severe thunderstorms across parts of the state Thursday evening and into the overnight hours. We do have some questions on how far to the southwest we could see severe storms in the area outlined as level 2 out of 5 risk, with some guidance hinting that dew points will be lower and temperatures will be higher than what the NBM has. Things will also be very dependent on the timing of the cold front. Highs on Thursday will be in the lower 80s northwest to lower 90s southeast, with dew points in the 60s central and east that will make it feel pretty humid for another day. Friday will be much cooler and less humid in the post-frontal air mass, with highs dropping down into the 70s. There could be a few isolated showers and non-severe thunderstorms from the influence of cyclonic flow aloft as the upper low exits to the east, but blended POPs are only around 10 to 20 percent and taper off in the afternoon. We then dry out and warm up through the weekend with zonal flow aloft dominating, with highs back into the widespread 80s for Saturday and Sunday. Precipitation chances return to start the work week with temperatures cooling into midweek. NSSL machine learning guidance has some low probabilities for severe weather Monday and Tuesday, and then again looking further ahead to next weekend when the NBM has temperatures warming up again. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1248 AM CDT Wed Jul 9 2025 VFR conditions generally expected through the TAF period. Southeasterly winds will get a bit breezy this afternoon, especially central and east, with winds shifting to northwesterly across western North Dakota. Chances for showers and thunderstorms increase late in the TAF period, although too low of confidence in timing and location to include at any specific terminal with this update. A few storms may become strong to severe with large hail and damaging, erratic winds as the primary threats. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Jones AVIATION...Jones