textproduct: Bismarck

KEY MESSAGES

- Cooler temperatures through the weekend, though still above normal.

- Widespread shower and thunderstorm chances return this weekend, followed by near-daily low to medium chances next week.

- Marginal (level 1 out of 5) severe weather threat Saturday afternoon/evening over far southwest North Dakota.

UPDATE

Issued at 1014 PM CDT Fri May 29 2026

Winds continue to diminish across the area with a few showers moving across south central North Dakota. No updates are needed at this time, as the forecast remains on track.

UPDATE Issued at 635 PM CDT Fri May 29 2026

Light scattered showers continue to move across the Devils Lake Basin and the James River Valley. There is hardly any instability across the region to warrant any thunderstorms tonight. No updates need to the forecast, as the forecast remains on track.

DISCUSSION

Issued at 230 PM CDT Fri May 29 2026

Currently weak southerly flow exists at the upper levels. A low pressure that was in California, is now in southern Nevada. Downstream a ridge is over the eastern half of the CONUS. At the surface, a low pressure sits in eastern Montana, creating southerly surface flow. The western half of North Dakota has a tight pressure gradient off the low, where winds are gusting to 50 mph. A Wind Advisory is in place across the west and north central through 02z tonight. In the warm moist conveyor belt stretching from the Gulf of America into eastern North Dakota and southern Canada, light rain showers.

Tonight through this weekend that upper level low will start to move northeast towards the Plains, at the same time the surface low will move into the state. With the diffluent southwest flow aloft and the surface low, widespread showers and thunderstorms will occur starting late tonight through Sunday. There is a marginal (level 1 of 5) risk of severe storms in southwestern North Dakota Saturday. Model soundings in this area have anywhere from 500 J/kg to 1100 J/kg. However, the CAPE profile is very skinny, and almost no 0-6km shear, so hail will likely be limited to small if at all. Wind will be the main concern as DCAPE will be around 1000 J/kg with an inverted V lower levels of the atmosphere. Low level shear around 20 kts will enhance the wind threat. For now, we are going with 60mph wind gusts. Sunday showers and thunderstorms will continue with a similar CAPE and shear profile. There could be a strong storm or two. This low pressure system will also bring cooler temperatures in the 70s and 80s, which is still above normal. Winds will remain strong as well from the pressure gradient off the low.

Next week the pattern remains in cyclonic flow from the upper level low eventually lingering in Montana. This in turn creates daily chances for showers and thunderstorms. Temperatures will remain above normal in the mid 70s north to lower 80s south.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 635 PM CDT Fri May 29 2026

Shower probabilities will increase through the night into tomorrow. Showers tonight and even thunderstorms tomorrow afternoon could cause MVFR conditions across the state and visibility reductions. Ceilings will increase by tomorrow afternoon, but there could remain some pockets of MVFR conditions. Southeast winds will continue through the TAF period with wind gusts diminishing this evening.

BIS WATCHES/WARNINGS/ADVISORIES

None.