textproduct: Bismarck

KEY MESSAGES

- Critical fire weather conditions in far southwest North Dakota through early evening.

- Chances for showers and thunderstorms increase through the holiday weekend. A few strong to severe thunderstorms could develop Saturday through Sunday.

- Well above normal temperatures today and Saturday, followed by a gradual cooling trend through the middle of next week.

UPDATE

Issued at 651 PM CDT Fri Sep 4 2026

There is an areas of thunderstorms going up the southwest and will likely stay sub severe as there is a lot of CIN that will prevent storms from strengthening. However, there is decent shear and CAPE that could support a stronger storm or two if they can over come the CIN. Added PoPs to match the current storms across the southwest. There is another wave that is moving across the north central South Dakota that could clip the southern James River Valley in North Dakota later tonight. The current forecast remains on track as of this time.

DISCUSSION

Issued at 308 PM CDT Fri Sep 4 2026

Critical fire weather conditions continue to be possible across the southwest through this evening. RH values have been slow to lower, although there appears to be a dry line now pushing through these far southwest areas. Thus will continue current Red Flag Warning as breezy southeast winds are still expected with these lowering RH values. Developing surface low in western MT will develop a warm front across northern and eastern ND tonight. Some weak showers are already forming along this boundary, with shower and thunderstorm activity forecast to increase somewhat this evening through tonight. The threat for severe weather remains low, although there remains high amounts of MUCAPE tonight. Shear is only modest, although hodographs would indicate some rotating cells are possible. Thus some near severe hail is possible. DCAPE and 0 to 3 km shear are also increased tonight, indicating some near severe winds are possible. The main threat tonight could be heavy rain, as PWAT values near 1.5 inches are forecast. Otherwise mild lows in the 60s are expected today with a steady southeast wind. Increased dewpoints will be found through the night bringing high RH recoveries. This could lead to some low clouds or perhaps fog tonight, although confidence was not high enough to place in fog in the forecast given the steady winds tonight. Surface low stalls across the area for Sunday as well as the mentioned warm front. A morning upper level wave could push overnight convection eastward through the morning. The stalled warm front will bring another hot day with highs in the mid 80s to mid 90s. This combined with continued high dewpoints will bring ample instability for Saturday. Shear remains modest for Saturday, although increases Saturday evening through the night. The result could be isolated severe thunderstorms Saturday through Saturday night. SPC has broaden the Marginal risk as a result for Saturday. It may still be somewhat conditional risk, as mid level ridging and warming overhead could cap the atmosphere somewhat. However, with high CAPE and modest shear, any storms that do develop could be come severe. High pwats of 1 to near 2 inches will also bring a heavy rain threat.

Surface low shifts slightly eastward and stalls Sunday and Monday, while influence from a broad upper trough moves in the state. The result will be increased chances for showers and thunderstorms for the rest of Labor Day Weekend. SPC has maintained a broad Marginal Risk for Sunday given high instability and at least modest shear. Isolated severe thunderstorms could continue into Labor Day, although instability is not as high. High pwats of 1 to 2 inches will also remain Sunday and Monday, bringing a localized heavy rain threat each day. With the stalled warm front across the state, temperatures will remain mild, especially in the south. From Tuesday to Wednesday, a stacked upper level low is projected over the southern Canadian prairie provinces on Tuesday before it quickly jets toward the northern Great Lakes and New England. This favors drier, slightly cooler, and windier conditions for western and central North Dakota Tuesday and Wednesday. Tuesday especially could see at least advisory level west winds. This combined with some lowering of RH could bring the next near critical to critical fire weather day especially in the west. Flow aloft may then transition to quasi- zonal by the end of next week, which could moderate temperatures to near normal values and return periodic lower chances for rain.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 651 PM CDT Fri Sep 4 2026

VFR conditions are forecast to continue across the region with maybe a low chance of fog forming early tomorrow morning. There is a low to medium chance of thunderstorms forming near KDIK in the next hour and KJMS late tonight into early tomorrow morning. Thunderstorms could cause temporary visibility reduction from heavy rain if they do occur over a terminal. Winds are forecast to remain out of the east to southeast through the period.

BIS WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 8 PM MDT this evening for NDZ031-040- 043.