textproduct: Bismarck

KEY MESSAGES

- Much colder tonight, with dangerously cold wind chills to continue across northeastern and portions of north central North Dakota through tonight.

- Another clipper system will bring low to medium chances (20 to 60%) for a wintry mix of snow, freezing rain, and sleet Friday from west to east.

- Windy conditions may also return Friday, with some blowing snow possible.

- After a cooler Saturday, temperatures are favored to warm back to near or above average leading up to Christmas.

UPDATE

Issued at 950 PM CST Thu Dec 18 2025

Made some minor timing and coverage adjustments to POPs overnight associated with the next embedded wave and sfc low set to move through the local area. Increasing southerly winds tonight through Friday AM ahead of a warm frontal zone, decreasing some along the sfc trough axis during the day, with gusty winds into Fri evening across the north behind a cold FROPA and rather strong CAA. Something we will need to keep an eye on with another 1-2 inches of new snow forecast across the north and this area seeing some recent snow (1-2 inches) over the past 24 hours. This will be especially true northeast where temperatures tomorrow will stay below freezing, thus blowable snow will remain coupled with expected new snow and the aforementioned strong winds. Winter Weather headlines are very possible for tomorrow and Friday night.

UPDATE Issued at 656 PM CST Thu Dec 18 2025

The main update for this evening was to sky cover, with increasing clouds west to east. Already BKN-OVC west, so sky grids were increased a bit through tonight. Still on track for an area of mixed precpitation moving from west to east late tonight through Friday AM, along with winds increasing out of the south, then transitioning to more westerly tomorrow.

DISCUSSION

Issued at 245 PM CST Thu Dec 18 2025

Conditions have greatly improved this afternoon, thus all remaining High Wind Warning, Winter Weather Advisory, and Blizzard Warning products have been expired or cancelled. Strong low pressure system will exit the state tonight, bringing a brief period of high pressure to much of the state. This high pressure will bring in cold air from the north with overnight lows below zero for most areas except the southwest. The coldest areas will be in the north central and northeast, where some light winds may linger. Thus extended the Cold Weather Advisory through the night and Friday morning in this area. As this high moves east later tonight a breezy return southerly flow ahead of the next clipper system looks to return. This could bring some patchy blowing snow. The developing warm front from this low could also bring some snow showers to the west late tonight.

The next clipper system then moves across the state Friday. Warm front lifts from west to east Friday morning. Most hi-res models have this bringing a band of snow ending as freezing rain. Both snow and ice accumulations may be light but still may approach advisory level impacts. Main concern is some dry air being introduced in the lower levels with the southerly flow. Given this uncertainty held off on any advisories for now, although it is important to know if this warm front can overcome the dry air, impacts to the morning commute from snow and ice is possible. Cold front from this system then moves through Friday afternoon, brining strong westerly winds and lingering chances of light snow. Push of cold air advection and pressure rises from this front could bring advisory level winds, especially to the north with gusts approaching 55 mph. Blended NBM/NBM90th data for wind forecast, yet held off on any highlights given some slight discrepancies on the timing of this front. It is of note through that ECMWF EFI values are elevated for Friday and again Saturday to an extent. If strong winds materialize, blowing snow will also be of concern especially to any areas with fresh snowfall from today or Friday morning. Overall confidence fell just short of any highlights for Friday on this shift, yet the potential is there for another impactful wind and winter event. Warm front on Friday will bring mild temperatures to most areas with highs in the 40s west to the 30s east. Cold temperatures could then move in Friday night behind this front, with breezy winds and blowing snow perhaps continuing. This time period may also need to be monitored for Cold Weather Advisory potential in the north.

Breezy and cooler conditions are then expected for Saturday. Some patchy blowing snow may linger as a result. NBM has a dry forecast, although and upper level trough could perhaps bring some flurries or scattered light snow showers. Highs Saturday will be in the single digits north to teens and perhaps 20s south. Cold temperatures may again be found Saturday night, although lighter winds could limit the dangerous wind chill readings. Light southerly winds under flat ridging could then bring warming and mainly conditions on Sunday. Next week, zonal flow could swap back and forth from ridging to weak troughing. The result are large temperature spreads in the NBM, although the overall pattern is to stay somewhat near normal. Precipitation chances are also limited for next week at this time, and will once again depend on any weak wave moving through the zonal flow pattern. ECMWF EFI values also indicating strong winds are not likely to return next week.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 656 PM CST Thu Dec 18 2025

VFR conditions all terminals this evening, with increasing upper level clouds west to east. Winds will transition to southerly, and increase through the night as an area of surface low pressure approaches. After 06Z, an area of snow mixed with freezing rain and sleet is forecast to move from west to east across the state through Friday morning, maybe lingering into early afternoon for KJMS. This could bring MVFR to IFR conditions, though confidence of this occurring at any given terminal is low. Winds become more westerly as we progress through the day Friday, perhaps leading to some blowing snow and low level wind shear issues.

BIS WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory until noon CST Friday for NDZ004-005-012- 013.