textproduct: Bismarck

KEY MESSAGES

- Low to medium chances of showers and thunderstorms in western North Dakota late this afternoon and evening, and in central North Dakota tonight into Thursday. Isolated severe thunderstorms are possible, mainly in western North Dakota this evening.

- Low chances of thunderstorms Friday and Saturday, then medium to high chances for showers and thunderstorms Sunday through early next week.

- Expect a warming trend through the end of the week, then cooling somewhat late this weekend into early next week.

UPDATE

Issued at 629 PM CDT Wed Sep 2 2026

In general, the forecast remains on track for tonight. We're monitoring the progress of a few isolated showers and storms across eastern Montana and northwestern South Dakota. While convective inhibition is expected to increase over the next few hours with the loss of diurnal heating, it's possible some of this activity could make it to western North Dakota before decreasing in intensity late tonight. While chances remain low (20-30%), there is an outside chance of a rouge severe storm sneaking into western North Dakota before midnight.

DISCUSSION

Issued at 249 PM CDT Wed Sep 2 2026

Southwesterly flow aloft continues across the Northern Plains as a warm front moves through eastern Montana into North Dakota later this evening. Storms could fire along the front this evening as ample instability remains in place across eastern Montana into western North Dakota. However, forecast soundings show that there will be a very strong CAP the further east you go into North Dakota later this evening mainly impacting anything that wants to move in the south central. Some of the CAMs try to bring a stronger storm across the southwest this evening and a cluster of weaker storms across the northwest along the front. The southwest storms are less in coverage now as the models have pulled back slightly. CAMs are increasing their coverage of storms developing in the early morning hours across the north central. SBCAPE tomorrow morning and afternoon will range around 1500-2500 j/kg of cape and 40 kts of shear. Storms will likely progress and strengthen by the early afternoon across the north central moving across eastern North Dakota into western Minnesota.

High temperatures this afternoon are forecast to warm into the 80s across the state. Overnight low temperatures tonight are forecast to drop down into the upper 50s to lower 60s. A weak low level jet will continue tonight moving eastward with the frontal progression. This could lead to breezy conditions and sustained storm development tonight across eastern and central North Dakota. Tomorrow, temperatures are forecast to warm into the warm upper 70s north to the upper 80s south. The warmer weather will move into the region by the end of the week as an upper level ridge builds across the region. Temperatures, Friday are forecast to warm into the upper 80s to lower 90s.

The upper level ridge is forecast to break down by this weekend leading to cooler temperatures. The ridge breaking down will open the door for an upper level low to move through the region Sunday into Memorial Day bringing forth increased chances of rain. The probabilities continue to increase for 1 inch of rain where the north now has around 50 percent shot of an inch of rain. The NBM 25th to 75th percentile for KBIS are around the 70s for later next week as the ridge breaks down.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 629 PM CDT Wed Sep 2 2026

Scattered showers and storms are forecast portions of northwestern and north-central North Dakota late tonight into Thursday morning. Mainly forecast to impact KXWA and KMOT, the primary concerns with this activity would be a few lightning strikes, gusty winds, small hail, and brief reductions in visibility from heavy rainfall. In general, timing for storms will be between 08Z-18Z Thursday.

Elsewhere, VFR conditions are forecast to prevail. Though, it should be noted that a low chance (under 20%) of an isolated storm is possible at KDIK, KBIS, KJMS, and surrounding locations, and amendments may be necessary if that occurs before 06Z.

Surface winds will be fairly consistent out of the east and southeast at around 10 to 15 knots with gusts around 20 to 25 knots over the first 12 hours of the TAF period. Then, surface winds will gradually become light and variable as a weak surface ridge slides across the region Thursday morning and early afternoon.

BIS WATCHES/WARNINGS/ADVISORIES

None.