textproduct: Bismarck

KEY MESSAGES

- An Extreme Heat Warning for all of western and central North Dakota from Saturday afternoon through Monday evening.

- Dangerously hot conditions with heat index values of 95 to 105 each day, and possibly up to 110 on Sunday. High temperatures will range from around 93 to 102 Saturday, 98 to 108 Sunday, and 91 to 106 Monday.

- Mainly dry conditions are expected through the hot spell.

- A little cooler with daily hit and miss thunderstorm chances next week.

DISCUSSION

Issued at 215 PM CDT Fri Jul 10 2026

Currently ridge is over the western half of the CONUS from a large upper level high sitting over the Desert Southwest. A low pressure and upper level trough sits off the coast of Washington state. At the surface that high pressure continues near the Four Corners region, along with most of the CONUS west of the Mississippi River.

Starting today the extreme heat will start to kick in as the large high pressure in the Southwest creates a Heat Dome. This compresses the air down to the surface and does not allow radiational cooling at night. Therefore temperatures each day have a large head start diurnally warming. As mentioned, low temperatures through early next week will only be allowed to cool to the lower 70s generally across North Dakota. High temperatures will get dangerously high, reaching the lower 100s by Sunday. An Extreme Heat Warning is in effect for Saturday through Monday night for temperatures up to 106 and heat indices near the same. Sunday and Monday will be the warmest days as the upper level high moves right into the state. Thats when the most dangerous heat will occur with highs up to 106.

On the northern extent of the large ridge that is over North Dakota, the ridge is slightly flatter and bringing moist pacific air east. This will create dew points in the upper 50s to mid 60s, increasing the heat index. As always in North Dakota, this high heat will be collocated with strong south winds. Saturday through Tuesday expect south winds gusting to 30 mph as well. Wednesday winds will turn easterly but continue gusting near 30 mph.

Next week the ridge will slowly break down and move slightly east, leading to southwest flow over eastern Montana. This could lead to a few showers and thunderstorms across the west and north middle to late week. The northern half of the state will cool back into the 80s as the backside of the ridge pulls in the slightly cooler mountain air off the Rockies. The southern half will likely stay in the low 90s. Looking at the NBM percentiles, there is a fair amount of uncertainty in this, likely due to the timing and shape of the ridge by mid next week.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 215 PM CDT Fri Jul 10 2026

VFR ceilings and visibility is expected at all terminals throughout the 18Z TAF period. Patchy fog may be possible across portions of the James River Valley late tonight into early Friday morning, though dry surface conditions and increasing surface winds is expected to greatly limit the coverage of any fog that does develop. Thus confidence remains too low to include visibility reductions at any given terminal at this time. Otherwise, light east winds this afternoon and evening will gradually turn to south overnight, starting to strengthen and become breezy through late Saturday morning and the end of the TAF period.

BIS WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning from 1 PM CDT /noon MDT/ Saturday to 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.