textproduct: Bismarck

KEY MESSAGES

- Long duration of bitterly cold temperatures with dangerous to life- threatening wind chills begins today and continues through the weekend.

- Coldest conditions expected this evening through Friday morning, with low temperatures around 25 to 35 below zero and wind chills around 45 to 55 below zero.

- Temperatures favored to warm next week, but could still remain below normal.

DISCUSSION

Issued at 417 AM CST Thu Jan 22 2026

A very deep closed upper level low is spinning from eastern Manitoba into western Ontario early this morning, placing northwest flow aloft over the Northern Plains. An Arctic cold front that can be seen through analyzed surface pressure rises is advancing southward through northern North Dakota and will continue on this trajectory through the morning. This frontal passage marks the beginning of our long-duration Arctic outbreak. Temperatures are forecast to keep falling through the day today, with perhaps a slight steadying trend near peak solar insolation. Afternoon highs are forecast to range from around zero southwest to near 20 below in the Turtle Mountains. Then from tonight into Friday morning, high pressure is forecast to slide into the region, with a northwest-to-southeast orientation. The most likely location of the surface ridge axis has tilted slightly eastward compared to previous forecasts, now extending from northwest to south central North Dakota. This doesn't really change our low temperature expectations in northwest North Dakota tonight, where we had already been advertising lower to mid 30s below. But the eastward shift of the southern extent of the surface high/ridge could trend overnight/Friday morning temperatures "warmer" (still 20s below) in the southwest and even colder in south central parts of the state. For now we maintained the 50th percentile of the NBM distribution for the low temperature forecast tonight, which limits sub-minus 30 values to western and far north central parts of the state. But this may need to be re-evaluated if the eastward shift in the surface high is maintained in future model updates.

Regardless of how cold temperatures fall tonight, dangerous to life- threatening wind chills are expected across all of western and central North Dakota. Wind chills have already fallen into the 30s below across northern parts of the state early this morning, and these will only continue to decrease as gusty northwest winds develop behind the Arctic frontal passage this morning and afternoon. By late morning we could already be facing 40 to 50 below wind chills from Williston to Jamestown and all points to the north. The plunge continues this evening through tonight and into Friday morning when life-threatening wind chills as low as 55 below are anticipated for many areas north and east of the Missouri River. Far northern parts of the state could see over 12 consecutive hours of wind chills colder than 50 below. These conditions are life- threatening if not properly dressed in multiple layers with no exposed skin, and are still quite dangerous even if dressed properly. Minimum wind chills closer to 45 below will be more common to the south and west of the Missouri River, which are still dangerous and can cause frostbite in less than 10 minutes. Even though the high pressure could render winds to be very light, it only takes a 5 mph breath of wind to create a wind chill of 45 below with an air temperature of 30 below.

Friday is expected to be the coldest daytime period of this Arctic outbreak. Deterministic NBM guidance continues to exhibit an unrealistic warm bias that is placing its maximum temperature projections in the 90th to 95th percentile range. We have limited the high temperature forecast on Friday to be no warmer than 1) the NBM 90th percentile or 2) the previously issued forecast. This keeps teens below for all but the far southwest. Friday night will not be as cold as tonight as a period of weak warm air advection commences, but still expecting teens and 20s below given daytime highs are not expected to be that much warmer. Highs on Saturday could actually rise above zero south and west of the Missouri River, with mostly single digits below elsewhere and perhaps still teens below far north central. A reinforcing shot of Arctic air is then forecast to arrive Saturday night with lows once again in the teens and 20s below. The heart of this secondary lob of Arctic air could shift into eastern North Dakota by Sunday afternoon, allowing the western half of the state to rise above zero.

Daytime wind chills on Friday are likely to remain in the 20s and 30s below, followed by teens and 20s below for maximum wind chills Saturday afternoon. Both Friday and Saturday nights have widespread minimum wind chills forecast in the 30s and 40s below. No changes are needed to the Extreme Cold Warnings that are currently in effect.

Mostly dry weather is expected through the weekend, but there is some potential for flurries or light snow at times along the baroclinic zone that marks the southwestward extend of the Arctic air mass, including early this morning. This would mainly be for just southwest North Dakota. However, ensembles are coming into better agreement on a couple of shortwave passages Friday through Saturday night that are producing low to medium chances for measurable snow (using a 10:1 ratio, which is likely too low for this type of environment). But at least the first of the two shortwaves, perhaps both, will have to contend with surface high pressure that could greatly limit any snow potential. Will maintain the mostly dry forecast (less than 10 percent chance except in the far southwest) provided by the NBM for now.

Confidence remains high in a predominant northwest flow pattern continuing through next week, but low on the western and southern regional extent of Arctic air. We can say with a fairly high degree of confidence that any Arctic air that intrudes our area next week will not be as intense as what we are about to experience over the next 36 to 48 hours. Ensemble cluster analysis paired with deterministic guidance would seemingly imply another round of Arctic air is likely at some point next week, but there is uncertainty in both timing and magnitude (but again, still high confidence in it not being as cold as late this week). It also seems likely that there will be a few shortwaves embedded in the northwest flow next week. The highest snow chances associated with any given wave are likely to be along the baroclinic zone, but again its location is uncertain and could vary from day-to-day. The NBM maintains a mostly dry forecast next week, but has introduced a 10 to 20 percent chance of snow late Tuesday, which does appear to line up with a projected upper level jet streak that is being picked up on by 3 out of 4 ensemble clusters.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 417 AM CST Thu Jan 22 2026

Isolated light snow showers/flurries under MVFR to low VFR ceilings remain possible early this morning, especially in western North Dakota. Winds will remain out of the northwest, breezy at times some areas. Generally VFR conditions with breezy northwest winds are forecast later this morning through the afternoon.

BIS WATCHES/WARNINGS/ADVISORIES

Extreme Cold Warning until noon CST Sunday for NDZ001>005- 009>013-021>023-025-035>037-046>048-050-051. Extreme Cold Warning from 6 PM CST /5 PM MST/ this evening to noon CST /11 AM MST/ Friday for NDZ017>020-031>034-040>045.