textproduct: Bismarck

KEY MESSAGES

- Areas of dense fog possible across parts of western North Dakota Wednesday morning, and across much of western and central North Dakota Wednesday night through Thanksgiving morning.

- There are medium to high chances (60-80 percent) for light accumulating snowfall (up to 3 inches) Friday and Friday night across portions of western and central North Dakota.

- Well below normal temperatures are favored for the weekend after Thanksgiving and into early next week. Wind chill temperatures as low as 25 below zero will be possible both Saturday night and Sunday night.

UPDATE

Issued at 132 AM CST Wed Nov 26 2025

Main forecast update was to sky cover based on latest satellite imagery and trends. Hard to find any given model depicting reality, so hand-drawn sky cover grids were done through this morning. Area of low stratus pushing off to the south faster than models had earlier shown, with a some mid level clouds also trending conditions BKN-OVC for a period at various locations. Will also maintain fog as is with this update. Thus far nothing widespread or needing elevated messaging.

UPDATE Issued at 900 PM CST Tue Nov 25 2025

The Winter Storm Warning has been cancelled. A few light flurries could persist through the evening in the southern James River Valley, but accumulating snow has ended. Patchy blowing and drifting snow will continue late this evening, diminishing overnight as winds relax.

Attention now turns to what could be a prolonged and widespread dense fog event. Confidence in dense fog is higher Wednesday night into Thanksgiving morning, but western parts of the state could see some later tonight into Wednesday morning as well. This is especially true in the northwest where low clouds have eroded and dense fog has already been reported at Plentywood, MT. Recent satellite imagery suggests this may be starting spread into Divide and Williams Counties. Forecast conditions seem highly favorable for widespread dense fog Wednesday night as a surface ridge axis resides over fresh snowfall.

UPDATE Issued at 619 PM CST Tue Nov 25 2025

The Winter Weather Advisory has been cancelled. Conditions have greatly improved outside of the southern James River Valley, where a Winter Storm Warning remains in effect. Still could see patchy blowing and drifting snow through the evening, and roads are likely to remain or become very slick.

The main concern for the short term period is the potential for fog development later tonight. Stratus is beginning to retreat from western North Dakota where a surface ridge is forecast to build in through tonight. This could promote a favorable setup for fog formation with light winds and differential cooling along the edge of the stratus, and surface dewpoint depressions are already near zero. Some models maintain fog, or perhaps very low clouds, through the day tomorrow and then show potential for a widespread dense fog event from northwest to south central North Dakota Wednesday night.

UPDATE Issued at 348 PM CST Tue Nov 25 2025

Canceled the Winter Weather Advisory for the northern tier of counties now that the snow has fully left the area. Blowing snow is not a major concern with how wet it has been.

DISCUSSION

Issued at 245 PM CST Tue Nov 25 2025

Currently the upper level low is maturing and deepening over northeastern South Dakota. There is an obvious dry slot wrapping in over southwest Minnesota, with a warm front moving through southern Minnesota. The surface low is almost in the same spot, so the low pressure system should be stacked at this point and continue to create high snowfall rates and amounts.

Here in western and central North Dakota, the snow has ended across the west and north central. Fog has now formed in the west and north as the wet snow starts to evaporate. In the south central a band of snow has formed in the diffluent flow as the low pulls away. It is currently moving east through Bismarck/Mandan. We had to update the NBM forecast to account for this since it had no snow there anymore. Snow is also starting to let up in the southeast. We have not received any recent reports, but it looks like the upgrade to a warning has worked out. Overall winds underperformed since the surface low was further south into South Dakota than forecasted. Still, blowing snow is possible through this evening, especially in the southeast. High pressure has formed in Montana under northwest flow and will push into the state overnight. With this, overnight lows will be in the single digits to teens.

The rest of this week will be much colder, about 10 degrees below average highs (mid 30s). Strong northwest flow will dominate. Friday another system looks to impact the Northern Plains. A shortwave will dig through Montana, producing a Northern Rockies low. Confidence is increasing in this event as it has been in the models for a few days now. With this a few inches are possible but it should not be as much as the current storm. Timing as of now looks like Friday early afternoon through Saturday evening. This low will wrap even colder air down from Canada, cooling our highs down to the teens. Low temperatures will likely be in the negatives with wind chills even lower. We will continue to closely monitor this, especially with the holiday weekend travel.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 132 AM CST Wed Nov 26 2025

MVFR ceilings at both KBIS and KJMS should improve early this morning. Other terminals mainly VFR. Exception will be areas of IFR-LIFR ceilings as fog develops this morning, which should be mainly over western terminals (KDIK and KXWA). Winds remain out of the northwest central and east through the 06Z period, and more light and variable west. Another period of IFR-LIFR cigs and vis expected Wed evening into Thu morning west and central.

BIS WATCHES/WARNINGS/ADVISORIES

None.