textproduct: Bismarck

KEY MESSAGES

- Low to medium chances for freezing drizzle moving from northeast to southwest across western and central North Dakota late tonight through Wednesday morning.

- Medium to high chances for light snow accumulations (less than an inch) north central into the northern James river Valley late tonight into Wednesday morning. Low chances for at least an inch of snow around the Turtle Mountains.

- Low chances for fog developing northwest and central tonight into Wednesday morning.

- Mild temperatures in the upper teens to upper 20s tonight. Then temperatures falling through the day Wednesday for most areas. Highs northwest and central will be early in the day. Still mild southwest though, with highs in the lower 30s.

- Large spread in temperatures from northeast (colder) to southwest (warmer) through the end of the week.

UPDATE

Issued at 758 PM CST Tue Dec 30 2025

Forecast confidence is increasing in a low- to moderate-impact freezing drizzle event across much of western and central North Dakota late tonight through Wednesday morning.

A large area of stratus blankets the eastern half of the state this evening, with its western extent near Highway 83. Despite broad warm air advection and +20 kt winds in the lower levels to the west of the stratus, model soundings and visibility fields do show fog developing later this evening, mainly from Lake Oahe up towards Mountrail County. A separate area of fog could migrate from northeast to southwest North Dakota along the leading edge of the backdoor cold front later tonight into Wednesday morning. Forecast confidence in coverage and intensity of fog remains low, but any dense fog should quickly diminish after the frontal passage.

Just trailing the cold front, HRRR/RAP soundings and 2-D fields have been consistently showing a saturated near-surface layer with depth around or greater than 1 km, and upward vertical motion within the saturated layer driven by low level frontogenesis and orographic ascent in a predominant northeasterly surface flow. These model sounding profiles are highly analogous for freezing drizzle. The threat for freezing drizzle is expected to last for around 2 to 4 hours at any given location. At 6 AM CST, the highest freezing drizzle probabilities are forecast from around Crosby to Minot to Carrington. By 9 AM CST, the highest probabilities shift southwestward to around Williston to Bismarck to Wishek. As the afternoon approaches, confidence in the freezing drizzle potential decreases as it shifts into southwest North Dakota, with recent HRRR/RAP soundings showing unfavorable saturated layer depth at Bowman, and unfavorable vertical motion profiles at Dickinson.

There are 2 possible caveats to freezing drizzle being the primary precipitation type, mostly affecting northern parts of the state: 1) ice crystal production in more deeply saturated mid levels could provide a seeder feeder mechanism for ice nucleation in the near- surface saturated layer, but this appears to only be possible in north central North Dakota near the beginning of the freezing drizzle threat window; and 2) the lowest 0.5 km of the near surface saturated layer could have temperatures cool enough (below -10 C) to introduce ice nucleation, which would favor a transition from freezing drizzle to flurries. The probability of flurries rather than freezing drizzle is not high enough to include in the forecast at this time, and it would only happen near the end time of the freezing drizzle threat across northwest and central North Dakota.

A 20 to 40 percent chance of freezing drizzle has been added to the forecast. If rapid refresh model trends continue to support the freezing drizzle, an increase in messaging will need to be considered.

DISCUSSION

Issued at 1258 PM CST Tue Dec 30 2025

Currently, skies were partly to mostly cloudy across western and central ND, with temperatures ranging from the mid 30s to mid 40s as a warm front has pushed through the entire state. Precipitation has pretty much pushed east of the forecast area. there was a brief period of UP recently near Bottineau, but amazingly air temperatures and surface temperatures were both above freezing and precip was very light. There was additional precipitation over southwest Manitoba, but it was moving southeast and currently looks like it may just miss the north central this afternoon.

The next wave tracks through the forecast area this evening through Wednesday morning. Currently, guidance suggests that snowfall with this system will be mainly confined to the north central into the James River Valley, with only light accumulations (less than and inch). Only the Turtle Mountains area is seeing low probabilities for an inch or more of snow.

Probably the more interesting and possibly the more impactful story could be the temperature trend through tomorrow and the possibility for low stratus/fog and possibly some freezing drizzle somewhere across northwest and central ND.

The clipper that pushed through last night into this morning will push a backdoor cold front back into western/central ND tonight. Behind the next clipper (that brings the light snow to north central into eastern ND) will have a reinforcing shot of cold air with it, that pushes the cold front west through the state. After a mild night tonight with lows mostly in the 20s. Temperatures most areas will fall through the day Wednesday. Thus highs will be early in the morning. The southwest looks to be the only areas that sees any significant temperature rises tomorrow afternoon. Late afternoon temperature are forecast to be below zero around the Turtle Mountains, and in the single digits above zero most areas in the northwest and east of the Highway 83 corridor in central ND.

Another forecast issue is the potential for low stratus and fog to develop along the westward pushing cold front late tonight into Wednesday morning. Forecast RAP/HRRR low level RH suggest an areas of stratus pushing from northeast to southwest this evening and overnight, possibly reaching the far southwest Wednesday before beginning to work back to the east. Don't have a good feeling about the potential for fog, and especially drizzle/freezing drizzle this evening into tonight. Did end up adding an area of patchy fog from northwest to southeast across the forecast area, similar to the area covered by the NBM probability for visibilities less than 3SM (generally 20 to 30 percent in this area). On Wednesday, and into New Years Day morning, if this low status remains along the baroclinic zone, think the potential for fog and flurries/freezing drizzle may increase. Will hold off on anything more than the patchy fog for now though. Certainly something to monitor going forward given the Holiday and all. Otherwise New Year's Day and Friday look to be mainly dry, with low chances for light snow, mainly north and east over the weekend.

The wide range in temperatures will continue through the Holiday weekend, with warmest temperatures southwest to coldest in the Turtle Mountains area. High temperatures in the mid 40s will be possible over the weekend in southwest North Dakota.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 758 PM CST Tue Dec 30 2025

The 00z TAF cycle starts out with MVFR ceilings across the eastern half of North Dakota. These are likely to persist through the evening and could expand westward. There is also a potential for fog developing just to the west of the stratus in central North Dakota later this evening into the overnight hours.

Areas to the northeast of KMOT and KJMS are likely to see a period of light snow later tonight, with IFR visibility. This should not reach either of those TAF sites.

A northwest-to-southeast oriented cold front will move from northeast to southwest across western and central North Dakota late tonight through Wednesday morning. The frontal passage could bring a variety of aviation impacts to all terminals, including 1) an initial period of IFR to LIFR ceilings and freezing fog/mist reducing visibility; and 2) a 2 to 4 hour period of light freezing drizzle trailing the front, with mostly IFR ceilings. The chance of freezing drizzle becomes lower as it reaches southwest North Dakota around midday, but IFR ceilings appear likely to persist from KXWA to KDIK through the afternoon, along with MVFR ceilings from KMOT to KBIS to KJMS.

Winds will primarily be westerly around 5-10 kts through this evening, switching to the northeast with the passage of the cold front.

BIS WATCHES/WARNINGS/ADVISORIES

None.