textproduct: Bismarck

KEY MESSAGES

- Areas of freezing drizzle and light snow across southwest and south central North Dakota this morning.

- Near daily chances for light snow through Tuesday.

- High confidence in 1 to 2 inches of snow along and to the south and west of the Missouri River tonight through Saturday, with locally higher amounts up to 4 inches in southwest parts of the state.

- A more impactful system could bring strong winds along with both rain and snow (medium to high chances) across the region Monday night through Tuesday night.

- Near average temperatures today, below average this weekend, above average Monday and Tuesday, then below average favored again the second half of next week.

UPDATE

Issued at 650 AM CST Fri Dec 5 2025

Surface observations and webcams continue to indicate widespread mixed precipitation across the southern half of our forecast area early this morning. Only a few tenths of an inch of snow have been reported across western and south central parts of the state since late last evening, but it was a wet and slippery snow and there is now increasing concern in a thin layer of ice coating over it. Observed, analysis, and forecast soundings are atypical for freezing drizzle, so there is low confidence on how long this threat will continue and how impactful it may become. A Special Weather Statement has been issued to cover this hazard, and the gridded forecast has been updated accordingly.

DISCUSSION

Issued at 509 AM CST Fri Dec 5 2025

Synopsis: A persistent northwest flow pattern over the Northern Plains will bring a parade of clippers across the region through next week. Ensembles are fairly consistent in the timing and placement of each system through Tuesday, with notable differences among ensemble clusters emerging thereafter. This pattern results in a forecast that contains repeated chances for snow (with mixed precipitation at times), wildly varying temperatures, and periods of breezy, if not windy conditions.

Today: Surface low pressure is analyzed over southeast North Dakota early this morning, with the parent mid level trough dropping into western North Dakota. Snow has not been nearly as widespread as anticipated during the overnight hours, and some automated observations continue to indicate mixed phase hydrometeors, including freezing drizzle. Areas of light precipitation are likely to continue along and ahead of the southward surging cold front attendant to the surface low this morning, which has already reached from around Williston to Fargo. There could also be a separate area of flurries crossing northern parts of the state later this morning from weak DCVA. Most of the precipitation should exit or diminish by the afternoon, but there are two exceptions. One is the potential for light lake effect snow to the south-southeast of Lake Sakakawea as low level temperatures cool below -10 C in a north-northwest flow over the lake. This would particularly favor locations downwind of the Van Hook Arm from northwest to central Mercer County for a period of lake effect snow with light accumulations possible. There could also be some light snow along a baroclinic zone in southwest North Dakota this afternoon, with no accumulation expected. Otherwise, expect near steady to falling temperatures around 20 degrees north to 30 degrees southwest this afternoon as another surge of Arctic air approaches from southern Canada. Breezy conditions are also expected this afternoon.

Tonight-Saturday night: The next wave is forecast to bring accumulating snow to western and south central parts of the state late tonight through Saturday evening. There is uncertainty in the northward extent of the snow as it will be contending with a dry and cold northeasterly surface flow eminating from an Arctic high pressure over Saskatchewan that has a tangential ridge axis extending down through the northern Red River Valley. The highest snow accumulation probabilities are generally along and to the south and west of the Missouri River, with medium to high chances for at least 1 inch and low to medium chances for exceeding 2 inches per the experimental NBM version 5.0 (similar probabilities are exhibited by the HREF). There is a low potential for a smaller area of higher amounts (most likely high-end amounts around 4 inches) driven by transient low level frontogenesis coupled with strong Q- vector convergence and a deep layer of steep lapse rates, but deterministic models are not in agreement whether these ingredients will simultaneously come to fruition in the same area. Aside from the snow, it will once again become colder tonight into Saturday, when daytime highs are only forecast to reach the single digits above zero north and east to near 20 in the southwest corner of the state. Most of the state is then forecast to see sub-zero lows Saturday night, but lighter winds should keep wind chills from falling colder than -20.

Sunday-Monday: A warm front is forecast to cross the region from west to east Sunday afternoon through Sunday night. The western half of the state could see around a 10 degree improvement in afternoon temperatures from Saturday to Sunday, while the eastern half struggles to rise out of the single digits. A band of light snow is also favored to accompany the warm front, with ensembles showing medium to high probabilities for measurable snow, but very low probabilities for exceeding 1 inch (less than 20 percent). Near- steady or rising temperatures are forecast Sunday night, followed by highs on Monday rebounding to the mid 20s northeast to mid 30s southwest. The shortwave that is responsible for the Sunday warm front could bring some light snow to north central and eastern parts of the state on Monday. Western North Dakota could see windy conditions in the warm sector on Monday. The cold front attendant to this wave looks to be much weaker and is barely expected to impact temperatures.

Monday night-Tuesday night: The warm front attendant to the next system is forecast arrive in western North Dakota as early as late Monday night. There is unusually high ensemble agreement given the time range and pattern that this clipper will be the strongest in this series, with a surface low forecast to cross the state from northwest to southeast during the day Tuesday. There are high probabilities for precipitation with this system, including a medium potential for at least 0.25" QPF from northwest to east central North Dakota. Precipitation types look to be an issue across western and south central North Dakota. There is high confidence that it will be warm enough both above and at the surface for precipitation to fall as rain over the aforementioned areas from late morning through the afternoon. What is less certain is whether the initial precpitation associated with the warm front will arrive early enough to fall through a warm layer aloft (high probabilities for 850 mb temperatures above freezing) onto surface temperatures that are still below freezing. Both deterministic and ensemble guidance hint at this potential, but there is not enough consistency to begin widely advertising an icing threat at this time. Accumulating snow also seems very likely with this system to the north and east of the Missouri River, but climatologically low snow ratios render the threshold probabilities of 0.25" QPF equivalent to those for around 1 to 2 inches of snow. Finally, deterministic guidance and the conceptual model suggest this system could produce very strong winds, and there is a shift-of-tails showing up in the ECMWF EFI wind gusts fields, indicating a low probability of high-impact wind event.

As mentioned in the opening paragraph, there is far less certainty and greater ensemble spread beginning mid next week, despite confidence remaining high in the synoptic northwest flow pattern continuing. The NBM maintains a 20 to 30 percent chance of snow through Thursday, and despite large 25th-75th percentile ranges, there is a distinct shift colder in the NBM maximum and minimum temperature distributions.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 555 AM CST Fri Dec 5 2025

Light snow and patchy freezing drizzle remain possible across southwest and south central North Dakota early this morning, but chances diminish from north to south by early afternoon. Low ceilings are expected to prevail through this afternoon, with LIFR to MVFR heights early this morning transitioning to just MVFR this afternoon. Southwest North Dakota could maintain a low ceiling through tonight, including falling back to IFR. MVFR ceilings are also forecast to expand back across the western half of the state by early Saturday morning. Another round of snow is expected to enter western North Dakota late tonight, but may not reach the major terminals until near the end of this forecast period. Gusty northwesterly winds are expected later this morning through the afternoon, then becoming light and variable this evening into tonight, and easterly around 10 kts in western North Dakota later tonight.

BIS WATCHES/WARNINGS/ADVISORIES

None.