textproduct: Bismarck

KEY MESSAGES

- Widespread shower and thunderstorm chances to be found this weekend, followed by near-daily low to medium chances through the work week. Near to slightly above normal temperatures also expected during this time period.

- Marginal (level 1 out of 5) severe weather threat through this evening over far southwest North Dakota.

- Marginal severe threat returns again Sunday afternoon/evening over southwest and parts of south central North Dakota.

UPDATE

Issued at 1251 AM CDT Sun May 31 2026

For late night update main focus for thunderstorms remains over southwest and parts of south central North Dakota where a corridor of instability around 500-1000 J/Kg is noted, but deep layer shear is meager at best. Right now the main area of storms is a line stretching from northwest to southeast South Dakota now nudging into far southwest North Dakota and the other area is now lifting through south central North Dakota more or less centered over the Bismarck area.

UPDATE Issued at 924 PM CDT Sat May 30 2026

No big changes to the going forecast outside of updating latest POPs and winds. Did scale back on thunder mention with MUCAPE more focused west vs east.

UPDATE Issued at 633 PM CDT Sat May 30 2026

The forecast for tonight remains on track. Base of an upper level trough will continue to lift north across the Central Rockies into the Northern High Plains tonight, with a quasi- stationary sfc trough across western South Dakota north- northeast into eastern Montana. Showers and thunderstorm chances will continue under this pattern, with the more robust activity near the sfc trough this evening, and more scattered convection farther east of the trough. POPs were adjusted to better reflect latest radar imagery and trends, with other forecast elements blended to latest observations.

DISCUSSION

Issued at 228 PM CDT Sat May 30 2026

Surface low and broad upper level trough will continue to bring chances for showers and thunderstorms through tonight. Coverage has been fairly isolated to scattered so far today, and this trend may continue through tonight as the state in general may be too far east of the surface low. The exception being the southwest. Here ample instability could bring some isolated strong to severe thunderstorms this evening, with damaging winds and small hail being the main threat. Skinny CAPE and low shear will be the limiting factors for tonight, thus the overall severe weather threat is isolated tonight. Elsewhere could still see showers with a few non severe thunderstorms as increased moisture aloft moves in with the upper level trough. Showers with this feature will still be fairly scattered through tonight. Look for breezy southeast winds to continue tonight with lows in the 50s. Some southwestern areas could see a lighter southeast wind. If showers clear out then perhaps some patchy fog is possible in these areas. Sunday, surface low and upper level trough looks to shift just enough eastward to maintain isolated to scattered showers and thunderstorms across the area. SPC has maintained a Marginal Risk for severe weather in southwestern and south central portions. Instability, especially at the surface, is slightly increased tomorrow in these areas. Shear still remains lows, although the effective shear may be slightly improved. CAPE profiles also look slightly more robust. Thus the main threats Sunday will be wind gusts to 60 mph and hail up to an inch in size. Otherwise look for highs on Sunday in the 70s and breezy southeast winds to continue. Sunday night a weak cold front looks to push from west to east bringing more chances for showers and thunderstorms and shifting breezy southeast winds to breezy westerly winds. This front will also bring cooler low temperatures Sunday night in the 40s west to lower 50s east.

Mentioned cold front moves through then stalls on Monday. Along this stalled front could be lingering showers and thunderstorms, especially in the north and east. A breezy westerly wind could linger through Monday with slightly cooler temperatures also expected. Cutoff low in west central Canada will bring an unsettled southwest flow Tuesday and Wednesday, while increased moisture filters in from a southerly flow at the surface. The result could be the next chances for widespread showers and thunderstorms. CSU-MLP hinting some isolated severe thunderstorms are also possible with this pattern each day. The return flow is forecast to provide PWATs over an inch as well. Some models showing localized heavy rain possible, although NBM chances for over an inch in a 24 hour period Tuesday through Wednesday are around 10 to 20%. Temperatures through mid week look to remain near to slightly above normal. Some uncertainty remains later in the week. Early indications are the southwest flow pattern becomes more zonal. A slight increase in temperatures is possible, with disturbances in the westerly flow continuing slight to chance pops for showers and thunderstorms. CSU-MLP also showing some isolated severe weather possible. Overall look for a generic summer pattern with near normal temperatures and daily chances for showers and thunderstorms to start the month of June.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 1251 AM CDT Sun May 31 2026

Rain showers will continue moving through the area overnight through Sunday. Mainly MVFR ceilings are forecast, though there will be a period of IFR ceilings over various locations overnight into Sunday morning. Periods of thunderstorms will also be in the mix through the forecast period, mainly addressed with separate PROB30 groups.

BIS WATCHES/WARNINGS/ADVISORIES

None.