textproduct: Bismarck

KEY MESSAGES

- Dangerous heat today through Monday evening, with high temperatures and heat index values in the upper 90s to near 110, and overnight lows in the 70s tonight.

- Cooler north mid to late week, but still hot across southern North Dakota.

- Dry today through Tuesday daytime, then low to medium (20 to 40%) chances for thunderstorms Tuesday night through Wednesday.

- Near daily low (20%) chances for thunderstorms Thursday through the weekend.

UPDATE

Issued at 630 AM CDT Sun Jul 12 2026

No changes to the forecast needed for the early morning update.

DISCUSSION

Issued at 353 AM CDT Sun Jul 12 2026

Dangerous heat continues across western and central North Dakota today through Monday. Currently, skies were mostly clear across the area with temperatures mainly in the 70s. Very hot today with near record or record high temperatures expected. Heat index values this afternoon will range from around 100 to 110 degrees. This oppressive heat will produce major to extreme heat related impacts if you do not take appropriate precautions. The hottest temperatures today are expected to be in the far west central and southwest North Dakota. The highest heat indices will be across the northern half of the state, where humidity will be the highest. Lows tonight are forecast to be in the 70s, with many areas seeing mid and upper 70s. Record high minimum temperatures will be possible at all major reporting stations tonight.

Monday will bring minor relief to the far northwest as the upper level ridge flattens a bit and a cold front drops into the northern portion of the state. The hottest temperatures Monday will shift south and east, extending from far southwest into northeast North Dakota. The highest heat indices will also extend from southwest to northeast ND. It's possible we may be able to cancel a portion of the Extreme Heat Warning over northwest ND on Monday. Will visit that after we get through today. Most of forecast area will still be seeing forecast heat indices of 95 to 105 degrees on Monday.

Tuesday will definitely be a little cooler across the north as the aforementioned cold front sinks a little farther south. In general, areas along and south of the I-94 corridor will still see forecast highs of 95 to 105 with heat indices also ranging from 95 to 105. Forecast highs drop into the 80s along and north of the Highway 2 corridor.

There remains a lot of uncertainty in temperatures as we go through the rest of the week. NBM ensemble temperatures vary widely from north to south. On Wednesday the 25th/75th ensemble spread ranges from 82 to 92 at Williston, but from 98 to 103 at Hettinger. Thus the farther south, the higher the confidence, in the hot weather continuing through mid-week. As we get into the latter portions of the work week and the weekend, there is a definite downward tick in the ensemble forecast temperatures, but the spread remains rather large, thus confidence is low that a significant cooldown will occur later in the forecast period.

Precipitation chances remain near zero through the heatwave (Monday) with low to medium chances returning over northern ND Tuesday night into Wednesday as another shortwave tries to flatten the upper ridge. At this time the south looks mostly dry with this feature. Thereafter, a lot of uncertainty remains in the upper level flow pattern over the Northern Plains as the mean upper ridge pops up and gets flattened a number of times through the rest of the week, with hit and miss thunderstorm chances in the forecast with each ridge flattening. Current NBM pops are a spattering of mainly low (20%) pops Thursday through Sunday.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 630 AM CDT Sun Jul 12 2026

VFR conditions are expected at all TAF sites through the 12Z TAF period. Light southerly winds to begin the period. Winds increasing to around 15 to 25 knots across the areas by 16-18 UTC. Winds subside a little this evening. However, LLWS around 1000ft will be present at all Taf sites from around 04 UTC through 12 UTC.

BIS WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning until 1 AM CDT /midnight MDT/ Tuesday for NDZ001>005-009-010-012-013-017>020-022-023-025-031>033-035>037- 040>044-046>048-050-051-055>062.