textproduct: Bismarck

KEY MESSAGES

- Low to medium chances for light snow and freezing drizzle across northwest and central North Dakota this afternoon through tonight.

- Near to below normal temperatures through Saturday, then warming to above normal for most areas early to mid next week.

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

DISCUSSION

Issued at 248 PM CST Fri Jan 2 2026

Northwest flow aloft over the Northern Plains early this afternoon, with broad but mostly weak easterly surface flow from high pressure over the Red River Valley to lower pressure near the Northern Rockies. A mid level shortwave embedded in the northwest flow will bring low to medium chances for light snow accumulations (high probabilities for not exceeding 1 inch) across northern North Dakota and into the James River Valley this afternoon and evening. Along and to the south and west of these snow chances, a pool of low level moisture remains trapped under an inversion along a baroclinic zone from northwest to south central North Dakota. Low level warm air advection is forecast to intensify within the nearly saturated 0-1 km AGL layer through this afternoon and evening, which may provide enough lift to produce light freezing drizzle. There are several factors that point to this being a low-impact freezing drizzle event, including 1) potential for seeder feeder mechanism to induce ice nucleation in the lower saturated layer; 2) minimum saturated layer temperatures slightly cooler than -10 C at times in some areas; 3) forecast cloud heights slightly higher than what is typically associated with impactful freezing drizzle (greater than 1,000 ft); and 4) an unfavorable synoptic pattern for impactful freezing drizzle, per local research. Nevertheless, it takes very little freezing drizzle to cause impacts, so this threat will need to be monitored closely through the evening. The risk area for freezing drizzle is forecast to slowly expand and drift eastward this evening through tonight, and should quickly end by sunrise Saturday morning with the passage of a weak cold front. In southwest North Dakota, models that simulate surface visibility suggest fog redeveloping early Saturday morning, but this is in a post frontal air mass with elevated northwest winds above the surface. Included a patchy fog mention for this, but think it is more likely to be low stratus that could approach the surface along higher terrain.

Near-steady temperatures are forecast for the next 36 to 42 hours, ranging from the single digits above zero northeast to the 20s southwest. Most locations across western and central North Dakota carry no greater than a 10 degree Fahrenheit difference between forecast maximum and minimum temperatures this afternoon through Saturday night. A westerly 850 mb flow and mid to upper levels turning anticyclonic could finally allow some of the persistent cloud cover to clear on Saturday, but surface flow is already forecast to return to southeasterly by the end of the day. The probability for any precipitation on Saturday is very low.

Strengthening warm air advection is forecast Saturday night into Sunday as an upper level ridge and trailing shortwave slide across the region. Moderate to strong synoptic forcing, primarily from differential cyclonic vorticity advection, is forecast to move across northern North Dakota Sunday morning, where antecedent deep layer moisture is not all that low (at least compared to farther south). This introduces a low chance for very light precipitation reaching the surface. Unfortunately, a strong inversion with above freezing temperatures aloft and below freezing at the surface supports freezing rain as the favored precipitation type, with increasing probabilities for sleet mixing in towards the Turtle Mountains on account of maximum temperatures aloft closer to 0 C. Model guidance shows uncertainty on precipitation reaching the surface, with CAMs extending out that far ranging from nothing to the ultra-agressive 15Z RAP outcome of 0.10" ice in the northwest. Global ensembles' probabilities for measurable precipitation (of any type) are around 15 percent north to 5 percent south, which are around 5 percent higher than those in the NBM. Given what deterministic models are showing for forcing and moisture, in addition to steep mid level lapse rates, we think at least the NBM probabilities may be too low. Combine that with only needing trace amounts of freezing rain to produce impacts, we have introduced a low chance of freezing rain across northwest and north central North Dakota for Sunday morning.

Much warmer temperatures are forecast to begin pushing in from the southwest as surface flow finally turns westerly Sunday afternoon, which should also clear any lingering low stratus. While even the Turtle Mountains should jump into the teens for highs on Sunday, the southwest could be well into the 40s, perhaps touching on 50 degrees in the southwest corner of the state. Then for Monday, the high temperature forecast settles in the 20s northeast to 40s southwest, and remains there through at least Wednesday. 25th-75th NBM percentile spread of maximum temperatures over this time period is only around 5 to 10 degrees, which lends confidence to messaging above normal temperatures for most areas, although to be more nuanced it would be near normal northeast to well above normal southwest. Ensembles favor a quasi-zonal flow pattern through mid week with potential for some embedded impulses that at this time do not have enough predictability for mentionable precipitation chances.

Longer range guidance favors deeper longwave troughing developing over the western and central CONUS late next week. While it remains highly uncertain what might come of this pattern, cluster analysis reveals 2 distinct outcomes. The outcome favored by 60 percent of all global ensemble members is a split flow solution that could bring lighter precipitation across the state. The other solution that has 40 percent membership, but of that includes 90 percent of GEFS members, is more of a traditional Colorado low, but one that keeps higher impacts away from western and most of central North Dakota. The NBM shows a distinct cooling trend over this time period, but with increasing spread and still near normal for early January.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 248 PM CST Fri Jan 2 2026

Widespread IFR ceilings across much of western and central North Dakota this afternoon, with some embedded areas of LIFR. Meanwhile, north central parts of the state maintain a VFR ceiling. The general expectation is for low ceilings to prevail across western and south central North Dakota through the forecast period, though trending closer to MVFR levels. Confidence in KJMS improving to VFR this afternoon has lowered, but will still keep a prevailing period of VFR before higher confidence in low ceilings returning this evening. In north central parts of the state, including KMOT, MVFR ceilings are expected to spread back eastward this evening.

Light snow and patchy light freezing drizzle are possible across much of northwest and central North Dakota this afternoon through tonight. The highest probabilities for snow reducing visibility are from KXWA to KMOT and down towards KJMS, and all points to the north. Fog could also return to southwest parts of the state later tonight into Saturday morning. Mostly light and variable winds through the forecast period, except for 10-15 kt southeasterly winds in western North Dakota this afternoon.

BIS WATCHES/WARNINGS/ADVISORIES

None.