textproduct: Bismarck

KEY MESSAGES

- Above normal temperatures are forecast through the work week, then much cooler temperatures this weekend.

- Dry conditions through Thursday, then low to medium chances for showers Friday into Saturday.

- Breezy to windy Friday and Saturday.

UPDATE

Issued at 610 AM CDT Tue Oct 20 2026

Mostly clear and quiet this Tuesday morning. No updates needed at this time.

DISCUSSION

Issued at 400 AM CDT Tue Oct 20 2026

Currently skies were mostly clear across western and central ND with a light southerly surface flow and temperatures in the upper 30s to mid 40s.

A quasi-zonal upper level flow will persist over the local area today. A weak, dry cold front will propagate through the upper flow turning our southerly winds this morning to a northerly surface flow, from west to east with the frontal passage. Even with the cold front passage, temperatures are forecast to be similar (northwest ND) or warmer (southwest and central) than yesterday. We did utilize a blend of NBM and NBM90 guidance to trend temperatures warmer. NBM ensemble guidance has been around 3 to 7 degrees warmer than our observed temperatures since late last week.

Wednesday through Friday upper level ridging builds over the central portion of the U.S. ahead of an upper level trough developing in the eastern Pacific. Wednesday is forecast to be a little cooler than today as high pressure builds over the area behind the cold front passage, but a southerly return flow is already developing over western ND by Wednesday afternoon. This will set the stage for a couple of unseasonably warm days on Thursday and Friday. As mentioned in the previous discussion, normal highs for this time of year are in the low to mid 50s, so temperatures will be approaching 20 degrees above normal. If our current trend of cooler than observed forecast high temperatures continues, which I suspect it may, Bismarck and Dickinson could see near record highs Thursday and Friday.

On Friday, the aforementioned upper trough over the eastern Pacific lifts into the Northern Rockies, with a surface low over eastern Montana/western North Dakota by 00Z Saturday. With a surge of warm advection ahead of the surface low, and with strong shear lifting into the area, an isolated elevated thunderstorm can not be ruled out on Friday. The CSU machine learning page indicated a threat for thunder on Friday. We'll see how this trends through the week. Friday night into Saturday as the surface low lifts north into Canada, we see a surge of cold advection. Breezy southerly winds Friday shift west to northwest Friday night, with breezy to windy conditions expected Friday night, and Saturday as the upper level system winds up to our north. At this time it looks like mainly light precipitation amounts from low to medium precipitation chances in North Dakota. The better precipitation amounts currently track from central Montana, northeast through Saskatchewan and into northern Manitoba. We could see low chance for showers on Friday then possibly some wrap around precipitation clipping the northwest Friday night.

Given the warm temperatures and breezy conditions Friday, will need to monitor fire weather concerns. Currently the return of moisture with dew point temperatures climbing into the mid 50s is keeping minimum humidities above 30 percent over southwest ND, with sustained southerly winds around 20 to 25 mph. Would not be surprised to see some lower minRH values in the southwest Friday afternoon as short range guidance extends into Friday. Saturday will also be breezy to windy, but with much cooler temperatures. However, being in the dry sector of the system over Canada, we could see windy conditions combined with low afternoon humidities.

Cooler temperatures remain Sunday and into the beginning of next week with mostly dry conditions.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 610 AM CDT Tue Oct 20 2026

VFR conditions are expected through the 12Z TAF period. Light surface winds early this morning remain light southerly ahead of an approaching weak dry cold front. Winds turn northerly behind the cold front 5-10 mph from west to east today into early evening, then diminish this evening. Only some mid and high VFR clouds expected through the TAF period.

BIS WATCHES/WARNINGS/ADVISORIES

None.