textproduct: Bismarck

KEY MESSAGES

- Very hot conditions through the weekend, with dangerously high temperatures and heat index values around 100 to 105 degrees.

- The combination of hot, dry, and breezy conditions on Sunday may cause near-critical fire weather conditions in parts of western and central North Dakota.

- The very hot temperatures may continue into Monday southwest, with a slight drop in temperatures elsewhere. The rest of the week remains hot with highs mostly in the 90s, but with some reading above 100 degrees possible in southwest North Dakota.

- Daily low to medium (20-40%) chances for thunderstorms remain in the forecast through the work week.

UPDATE

Issued at 630 PM CDT Sat Jul 25 2026

Isolated weak radar returns linger over portions of the far southwest at the time of this early evening update. Later this evening into early tonight, showers and storms currently developing upstream in central Montana are expected to begin moving toward the ND/MT border. Short term CAMs continue to have difficulty resolving the longevity of these storms due to the fairly robust capping expected to be in place over western North Dakota by this time, though one or two models continue to propagate at least some showers and storms across western North Dakota into central North Dakota overnight. Considering this, have opted to spread low PoPs (less than 20 percent) overnight through early Sunday morning. In the scenario where storms do end up diminishing rapidly as they cross over the ND/MT border, there is some potential for isolated strong winds as the very hot and dry vertical column across western North Dakota would be supportive of heat bursts. All of that is to say, we will need to monitor conditions as we head into the evening.

DISCUSSION

Issued at 250 PM CDT Sat Jul 25 2026

Very hot temperatures continue across much of western and central North Dakota this Saturday afternoon. Hettinger had already reached 104 degrees as of noon MDT. Many other locations south and west of the Missouri River are also around the 100 degree mark early this afternoon. In Bismarck, our morning fog held temperatures down a bit through mid morning, but we are catching up quick with an early afternoon reading in the mid 90s. The Heat Advisory started at 1 PM CDT and no changes here with temperatures and/or heat indices in the 100-105 range for the Advisory area.

The risk for thunderstorms remains low tonight, especially over northern and eastern portions of the forecast area. The better forcing for ascent will remain over southeast Montana into northwest South Dakota, yet a stronger storm or two can not be ruled out in the far southwest, producing a marginally severe wind gust.

Sunday will be a repeat of today temperatures wise, with forecast highs once again expected to be over 100 degrees over much of the southwest and south central. Only slightly cooler temperatures in the 90s are anticipated along the International Border. The very hot temperatures should keep thunderstorm chances to a minimum. If anything, perhaps an isolated shower/storm brushing the International Border Sunday morning, and possibly some dissipating convection moving into the west later Sunday night. Most of the day will be sunny and hot. The threat for severe storms Sunday is minimal.

The very hot and dry conditions Sunday, combined with a dry cold front passage, may create near critical fire weather concerns Sunday afternoon and early evening. Afternoon relative humidities will drop to 12 to 18 percent across much of western North Dakota. Northwest winds will increase behind the dry cold front to 15 to 20 mph with gust to 30 mph. Due to the recent dry conditions, grasses have begun to cure and near critical fire weather conditions may be reached.

On Monday, the upper level ridge over the Northern Plains flattens a little bringing cooler temperatures northeast, but with very hot temperatures still possible in the southwest and far south central. Will hold off on any extensions of the Heat Advisory, but this is something that may be needed as we get closer to Monday. As was mentioned above, daytime thunderstorm activity will be suppressed due to the hot temperatures. A morning or overnight isolated thunderstorm can not be ruled out though.

The remainder of the work week will continue to bring hot temperatures, mainly in the 90s, but with some 100 degree readings still possible in the southwest. Overall though, not quite as hot as this weekend. Daily low chances (20-30%) thunderstorm chances will remain through the week but with a low predictability in when and where they may occur. There does look to be a little better chance of precipitation in the Wednesday/Thursday timeframe with another impulse that briefly flattens the mean upper level ridge.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 630 PM CDT Sat Jul 25 2026

VFR ceilings and visibility are generally expected at all terminals throughout the 00Z TAF period. Late this evening and tonight, scattered showers and a few thunderstorms may cross into western North Dakota and move into south central North Dakota through tomorrow morning. Confidence on coverage and location is very low, and thus no mentions have been included at any give TAF site. Otherwise, patchy fog is possible over portions of the James River Valley overnight, though confidence in visibility impacts at KJMS are also very low at this time. Light and variable winds are generally expected this evening tonight, before strengthening and turning cyclonically around a low pressure system passing to the north of the forecast area Sunday morning and afternoon. Wind speeds up to around 15 knots and gusts up to 25 knots are expected Sunday afternoon, mainly west.

BIS WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 9 PM CDT /8 PM MDT/ Sunday for NDZ017>020- 022-023-025-031>033-035>037-040>044-046>048-050-051-057>062.