206 FXUS63 KBIS 302012 AFDBISArea Forecast Discussion National Weather Service Bismarck ND 312 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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.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 /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 112 PM CDT Tue Sep 30 2025
VFR conditions will prevail through the forecast period. LLWS will be possible at the KBIS terminal along with over south central North Dakota this evening and overnight.
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.BIS WATCHES/WARNINGS/ADVISORIES... None.
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DISCUSSION...JJS AVIATION...JJS
NWS BIS Office Area Forecast Discussion