572 FXUS63 KBIS 010250 AFDBISArea Forecast Discussion National Weather Service Bismarck ND 950 PM CDT Tue Sep 30 2025
.KEY MESSAGES...
- High temperatures around 10 to 20 degrees above average expected Wednesday and Thursday.
- Cooler temperatures return to end the week, with temperatures dipping below average to start the upcoming week.
- Rain chances return across the area to end the week and start the upcoming week.
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.UPDATE... Issued at 950 PM CDT Tue Sep 30 2025
A few weak returns are starting to show up in eastern ND and eastern MT as a surface trough and upper level wave move through. These features could still bring a few isolated showers or thunderstorms to the west and east tonight. Slight PoPs in the forecast remain on track given current radar trends. Thus little needing updating at this time.
UPDATE Issued at 658 PM CDT Tue Sep 30 2025
Limited updates needed early this evening. Isolated showers have formed in the northeast, while some weak showers are trying to form in the south central areas near the SD/ND border. As a surface trough and upper level wave moves through tonight there could be a few thunderstorms in the west and east. There is some modest elevated cape and increased shear tonight, although the atmosphere is fairly dry and capped. Thus the current isolated thunderstorms chances in the forecast remain on track.
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.DISCUSSION... Issued at 244 PM CDT Tue Sep 30 2025
Current surface analysis places low along the Alberta/Saskatchewan border stretching into central/eastern Montana, while ridge stretches from Ontario into the Midwest. Upper level analysis places ridge over the Midwest into western Ontario, with deep low off the Pacific Northwest coast. Over our area, south/southeasterly winds continue between the aforementioned surface features, with some clouds noted mainly over the James River Valley region.
For tonight, a few showers and maybe a rumble or two of thunder will be possible over the James River Valley region as a modest wave lifts through the area, but expect and activity to be weak and isolated. Some additional showers possible late tonight over the west as aforementioned surface low lifts northeasterly and its affiliated trough passes over.
On Wednesday, with the exception of some lingering showers over the west, quiet weather is expected with another very warm day on tap as thermal ridge remains over the region. Highs remain around 10 to 20 degrees above average.
The warm temperatures continue into Thursday along with dry conditions. Changes start to come late Thursday into Friday as aforementioned upper low off the Pacific Northwest moves onshore and digs southerly as it opens up during its approach. This will start bringing precipitation chances to the area, along with some thunderstorms. Latest runs of the CSU Machine Learning Probabilities indicate a low chance for severe mainly over eastern portions of our area Friday into Saturday. Cooler air will also start gradually working its way into our area.
Going into early next week, precipitation chances linger over various parts of the area and temperatures drop below average per latest NBM guidance.
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.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 658 PM CDT Tue Sep 30 2025
Overall VFR conditions are expected through the forecast period. An isolated shower or thunderstorm is possible tonight into Wednesday morning in the east and the northwest. Only KXWA had high enough confidence for a PROB30 group. Breezy southerly winds will also be found tonight, lingering in the east on Wednesday, while winds become westerly across the west then central. Some low level wind shear is possible in central portions tonight, and remains in the KBIS TAF.
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.BIS WATCHES/WARNINGS/ADVISORIES... None.
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UPDATE... DISCUSSION...Anglin AVIATION...Anglin
NWS BIS Office Area Forecast Discussion