textproduct: Bismarck

KEY MESSAGES

- Much cooler but windy today, with critical fire weather conditions in southwest and parts of south central North Dakota.

- Periods of scattered showers and thunderstorms across much of the state today. A few storms could be strong to severe from south central North Dakota into the James River Valley.

- Highs in the 70s on Tuesday, then warming back up to the 80s and 90s by the end of the week.

DISCUSSION

Issued at 536 AM CDT Mon Aug 3 2026

An occluded upper low is spinning from Saskatchewan into Manitoba early this morning. A positively tilted trough axis extends southwestward from the low, with a shortwave at its base preparing to eject off the Northern Rockies. An inverted surface trough is analyzed from a low pressure over the Black Hills to the northern Red River Valley. The inverted trough extends vertically, with strong 850-700 mb warm air advection, frontogenesis, and moisture transport. This has resulted in scattered showers and isolated thunderstorms developing across much of western and central North Dakota early this morning. The most recent suite of CAMs was far too slow in developing this activity, but they do consolidate on a broader area of more persistent showers and thunderstorms shifting from south central into eastern North Dakota around 6 to 9 AM CDT. The convection is presently and forecast to remain elevated, with effective bulk shear ranging from as high as 55 kts from southwest to central North Dakota to as low as 30 kts in the southeast. So far, it appears that updrafts have not been able to realize the full extent of this shear and 1000-2000 J/kg MUCAPE, but recent model trends suggest this may change closer to sunrise. Periods of scattered showers and isolated thunderstorms are likely to continue through the afternoon as the upstream shortwave moves into the Northern Plains, but 00-06Z initialized CAMs have almost completely shifted any severe threat east of our forecast area. The HREF and RAP do maintain 1000-2000 J/kg of MUCAPE in the James River Valley through the afternoon though, with effective bulk shear there increasing closer to 50 kts by late afternoon. Any afternoon convection in this part of the state should also remain elevated, which keeps our confidence in the threat ceiling low.

The other concern for today is northerly winds increasing to around 25 to 30 mph with gusts as high as 40 mph through this afternoon. The upstream shortwave will bring a stronger push of cooler and drier air into the state, limiting highs to the upper 60s in the far northwest but still reaching the 80s across the south. Humidity falling as low as 25 percent in southwest North Dakota keeps critical fire weather conditions in the forecast through early evening. A Red Flag Warning remains in effect for most areas south and west of the Missouri River. See the fire section below for details.

Surface high pressure will begin building into the region on Tuesday as longwave troughing resides overhead. Forecast highs remain in the 70s for all of western and central North Dakota on Tuesday, and both tonight and Tuesday night could see widespread lows in the mid to upper 40s. Through the rest of the week, the longwave trough is forecast to slowly shift eastward, allowing the western CONUS upper ridge to build back closer to the Northern High Plains. This brings a projected warming trend heading into the weekend, with the NBM advertising highs in the 90s returning to the southwest quadrant of the state Friday and Saturday. The median 50th percentile spreads do increase to 10-15 degrees Fahrenheit, but the cooler side of the distribution shows a clear warming trend through at least Friday. Ensembles generally favor a transition to a quasi-zonal flow pattern this weekend into early next week, but there is at least one cluster each day that maintains northwest flow with an upper level ridge axis between the Northern Rockies and Northern Plains. After today, chances for measurable rain remain very low through the end of the week.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 536 AM CDT Mon Aug 3 2026

Scattered showers and thunderstorms are possible across much of the state this morning and afternoon. Brief MVFR/IFR visibility restrictions, MVFR ceilings, and gusty winds can be expected with heavier showers and storms. Small hail is also possible with stronger storms. Smoke may continue to reduce visibility at times today, but it is expected to clear from northwest to southeast this afternoon and evening. North-northeast to northwest winds will increase to 20-25 kts this afternoon, with gusts as high as 35 kts. Northwest winds will then diminish this evening into tonight, with VFR conditions prevailing.

FIRE WEATHER

Issued at 536 AM CDT Mon Aug 3 2026

A Red Flag Warning for critical fire weather conditions is in effect for areas south and west of the Missouri River, except McKenzie County, until 8 PM MDT. Recent forecast guidance has trended slightly windier, but with higher minimum RH. Still expecting sustained winds to increase near 30 mph this afternoon, with direction turning from north-northeast this morning to north-northwest by mid afternoon. Minimum humidity is still forecast to fall as low as 25 percent in far southwest North Dakota, but could hold closer to 30-35 percent in surrounding areas.

BIS WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 9 PM CDT /8 PM MDT/ this evening for NDZ018-031>033-040-041-043-044. Red Flag Warning from noon CDT /11 AM MDT/ today to 9 PM CDT /8 PM MDT/ this evening for NDZ019-020-034-042-045.