textproduct: Bismarck

KEY MESSAGES

- Isolated to scattered showers and thunderstorms expected this afternoon. A few storms could be severe.

- Windy on Tuesday, with near-critical to critical fire weather conditions across southwest and south central North Dakota.

- Unseasonably warm and humid today, then cooler Tuesday and Wednesday. A brief warm up on Thursday could be followed by much cooler temperatures next weekend.

DISCUSSION

Issued at 229 PM CDT Mon Sep 7 2026

A dynamic system continues impacting the forecast area. Currently, surface low is located over eastern Montana/southwestern North Dakota, while upper low is primarily over north central Montana propagating into south central Canada. For the most part, thunderstorms from earlier today have exited the CWA. However, another severe weather threat persists this afternoon, and seems especially focused along and west of Highway 83 where skies cleared out quicker in the day. RAP analysis suggests a narrow corridor of enhanced instability this afternoon that will be collocated with 40 to 50 kts of deep layer shear. Wherever this ultimately sets up would be the primary focus for severe weather. With bulk shear vectors generally perpendicular to the frontal boundary off the surface low, supercells are possible that could lead to large hail and damaging winds. A tornado or two cannot be ruled out, especially near the surface low.

By this evening, any remaining instability should rapidly decrease as dry air moves in, while CIN increases. Thus any severe weather threat should also diminish as the sun sets. After which, a few showers are possible mainly in the north on Tuesday, with additional rain chances overnight. Gusty westerly winds will develop Tuesday as the surface low lifts northeast, especially in the northern half of the state. Though pressure rises and CAA advection aren't the strongest, there was enough confidence to issue a Wind Advisory for most counties north of I94.

For Tuesday, the strongest winds are not collocated with the driest air. Still, critical fire weather conditions are possible in the far southwest. In addition, near critical conditions are expected in the remainder of the southwest and south central. Drier conditions and breezy winds could once again produce near critical to critical fire weather conditions across much of the southwest and south central on Thursday.

Beyond Tuesday, mostly dry conditions are favored through the remainder of the workweek. After which, widespread precipitation chances return Sunday and into early next week. Temperatures Tuesday and Wednesday will be seasonable before another brief warm-up Thursday. A cooling trend is then expected this weekend and into early next week with highs possibly in the upper 50s and 60s by early next week.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 102 PM CDT Mon Sep 7 2026

Scattered showers and a few thunderstorms persist in eastern, central, and parts of northwestern North Dakota early this afternoon. Additional development is possible as the afternoon goes on, which could lead to severe weather including gusty and erratic winds, as well as large hail. Placing exactly where these storms will develop remains a challenge so maintained PROB30s as needed. Shower and thunderstorm activity should rapidly diminish as the sun sets. Tuesday morning will be mostly dry, though gusty westerly winds will begin to develop, especially north of I94.

BIS WATCHES/WARNINGS/ADVISORIES

Wind Advisory from 7 AM CDT /6 AM MDT/ to 7 PM CDT /6 PM MDT/ Tuesday for NDZ001>005-009-010-012-013-017>019-022-023-025- 055>058.