textproduct: Bismarck

KEY MESSAGES

- Winter storm will continue to wind down from west to east this morning.

- Low chances for scattered light rain or freezing rain showers across northwest and central North Dakota tonight.

- Well below normal temperatures expected for most areas through Monday.

- Windy conditions expected Tuesday through Wednesday, with low to medium chances for light rain or snow.

UPDATE

Issued at 656 AM CDT Sat Apr 4 2026

The winter storm continues to unfold as expected, with the western edge of the snow now from around New Rockford to Fort Yates. Sheridan, Oliver, Morton, and Grant Counties were removed from the Winter Storm Warning for this update.

DISCUSSION

Issued at 443 AM CDT Sat Apr 4 2026

The closed upper low that has brought us a winter storm has spun into eastern South Dakota as of 4 AM CDT. The western edge of the shield of snowfall has now reached around Rugby to Elgin. Radar still shows some embedded enhanced snowfall rates from around Lake Oahe to the James River Valley. The entirety of the Winter Weather Advisory has now been cancelled, and the western edge of the Winter Storm Warning has been trimmed back to Sheridan, Burleigh, and Oliver through Sioux Counties. The snow is expected to continue ending from west to east through the morning, leaving behind a mostly cloudy and cool afternoon, with highs only around 35 to 40 where several inches of snow have fallen but closer to 50 along the Montana border from around Beach northward. Breezy northwest winds are still anticipated in south central and eastern North Dakota later this morning and afternoon, but not strong enough to cause impactful blowing and drifting snow given the heavy and wet nature of the snowfall.

A clipper system will move from northern Alberta this morning towards the western Great Lakes on Sunday. The attendant warm front could bring some scattered light showers across northwest and central North Dakota late this evening through early Sunday morning. Forecast maximum temperatures aloft are cold enough to support snow only in the Turtle Mountains area, yielding rain or freezing rain as an expected type elsewhere. Given CAM output for both surface temperatures and precipitation types, we blended some higher hourly temperatures into the forecast overnight to keep the western half of the state above freezing as the chance of light rain showers moves through. The risk of freezing rain as a type increases as the precipitation moves into eastern North Dakota early Sunday morning, but the point- specific probabilities for accumulating ice are very low. The 00Z HREF mean FRAM does show some pockets of 0.01" ice, but any impacts from freezing rain should be very short-lived and limited spatially. Previous forecasts had also mentioned a potential for a few thunderstorms, but while there is some model support for weak MUCAPE on the order of 100-200 J/kg, the probability of lightning is no longer high enough to advertise in any other forecast products.

The cold front attendant to clipper will sag into northern and eastern North Dakota during the day Sunday, keeping highs in the mid 30s east to mid and perhaps upper 40s far west. A strong isobaric gradient will increase northwest winds to around 20 to 30 mph across northern and eastern North Dakota during the day Sunday, slightly weaker to the southwest. A few CAMs hint at some light precipitation with the cold frontal passage in the morning, as well as diurnally driven cyclonic flow popcorn showers in the afternoon in eastern North Dakota, but these probabilities are not high enough to add to the forecast at this time.

A modified Arctic air mass tied to a ~1040 mb surface high (MSLP above the 99th climatological percentile for early April) will sink into the region Sunday night through Monday, keeping temperatures well below average. From late Monday night into Tuesday, a transient upper ridge will allow southerly return flow to increase as a potent upper low digs into the Northern Rockies. The warm sector of the approaching system could reach western North Dakota by the end of the day Tuesday, which would likely allow highs to reach the 50s and 60s. But it is more likely to remain in the 40s through central North Dakota and 30s in the east within a poor mixing regime. Tuesday will be windy out of the south around 20 to 30 mph, with gusts around 40 mph.

There is increased ensemble agreement on the base of the potent shortwave/closed low quickly moving through the region along the international border late Tuesday into Wednesday, but still with some timing and placement discrepancies and some clusters being heavily weighted by ensemble system type. Surface-based fields are not drastically different among each cluster though, with only light precipitation favored across northern North Dakota (medium chances for a tenth of an inch of QPF) and even lighter to no precipitation favored to the south. Any precipitation with this system would likely start as rain and then transition to snow in the north. But even the snowiest ensemble cluster only has a low chance of accumulations exceeding one inch (10:1 snow ratio) along the Canadian border over this time frame. There is still higher confidence in Wednesday being another windy day, with direction shifting to the northwest. Using the 850 mb level as a proxy for mean BL winds, maximum momentum transfer potential to the surface would produce surface gusts around 35 to 45 mph. Spread in the NBM distribution for highs on Wednesday remains large, but the deterministic output tends to favor the lower 50th percentile, keeping highs in the 40s. Longer-range ensemble guidance is now trending towards keeping temperatures below normal in an active pattern through the end of next week.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 656 AM CDT Sat Apr 4 2026

Snow producing mostly IFR visibility will continue to end from west to east across south central and eastern North Dakota this morning. Ceilings across southern North Dakota are mostly MVFR this morning, with some pockets of IFR and VFR. The general expectation is for ceilings to improve from west to east later this morning and afternoon, but there could be alternating periods of MVFR and VFR from KDIK to KBIS until then. VFR ceilings are expected across northern North Dakota, but there is a low chance for a brief period of MVFR moving over KXWA this morning. Northwest winds will become sustained around 10 kts in the west to 15-20 kts in the east this afternoon, with some higher gusts possible at KJMS and surrounding areas. Lighter westerly winds are expected this evening through tonight until a cold front enters far northwest North Dakota late tonight, turning winds to the northwest around 10-15 kts.

Later this evening through tonight, isolated to scattered light rain showers could move through northwest and central North Dakota, with precipitation changing over to a freezing rain/snow mix as it enters the eastern half of the state late tonight. At this time, both ceilings and visibility are expected to remain at VFR levels. A wintry mix could be approaching KJMS near the end of the forecast period.

BIS WATCHES/WARNINGS/ADVISORIES

Winter Storm Warning until 4 PM CDT this afternoon for NDZ023- 025-035>037-046>048-050-051. Winter Storm Warning until 1 PM CDT /noon MDT/ this afternoon for NDZ045.