textproduct: Bismarck

KEY MESSAGES

- Isolated to scattered thunderstorms will continue this afternoon into this evening. Primary hazard will be wind gusts to 70 mph, with a secondary hazard of ping pong ball size hail.

- High chances (60 to 90 percent) for scattered thunderstorms across southern North Dakota including the James River Valley on Thursday. A few storms could be severe and produce locally heavy rainfall.

- Cooler on Thursday, then becoming hot once again through the weekend.

DISCUSSION

Issued at 234 PM CDT Wed Jul 29 2026

Current surface analysis places low over northeast Wyoming, with inverted trough stretching to the north towards northwest North Dakota. Upper level analysis places high over New Mexico with ridge stretching to the north/northeast. Noted in the flow is a short wave pushing through eastern Montana/Wyoming into the Dakotas. This wave, along with the aforementioned trough, are leading to thunderstorm development over the area.

For the rest of this afternoon into this evening, showers and thunderstorms will continue to develop over the area then slowly push towards the east. Elevated instability (CAPE values around 2000 J/Kg) combined with very marginal shear remain in place, but what continues to be notable is the steep low level lapse rates, and forecast downdraft CAPE values around 1500 to 1800 J/Kg. Therefore, continue to believe that the primary threat with any storm will by strong wind gusts, with a lower secondary threat of large hail. Storms will continue into the evening, with guidance continuing to show diminishing in strength and coverage later in the evening.

The other ongoing issue is the hot temperatures today combined with somewhat elevated humidity. Therefore, we have previously issued a Heat Advisory, and plan to let that continue into early this evening.

On Thursday, a stronger short wave pushes into the area bringing greater coverage of showers and thunderstorms, particularly to southern portions of the area per latest guidance. Shear values through the day look marginal at best, with enough instability to not rule out the potential for an isolated severe storm. With that said, there is the potential for some locally heavy rainfall given the moisture in place and the possibility for multiple rounds of showers/storms.

Temperatures start to rebound on Friday, with the possibility of a stray shower/storm mainly over the north as a disturbance moves through.

Saturday into Sunday hot weather returns, with increasing winds ahead of a cold front on Sunday. This elevates the fire weather concerns, particularly over the west. This will bring cooler weather to start the work week with shower/storm chances.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 121 PM CDT Wed Jul 29 2026

Distant wildfire smoke will continue over parts of the area into this evening. This may lead to occasional periods of MVFR visibility. Scattered showers and thunderstorms will push into western North Dakota this afternoon, sliding east this evening before decreasing in coverage. Another disturbance moving through will bring additional showers and thunderstorms on Thursday.

BIS WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 8 PM CDT /7 PM MDT/ this evening for NDZ009-010-012-013-017>020-022-023-025-031>033-035>037-041-042- 044-046>048-050-051-056>062.