textproduct: Bismarck

KEY MESSAGES

- Frigid wind chills through Sunday morning over most locations north and east of the Missouri River, especially across the north where wind chills could fall as low as 40 below zero. - Well below average temperatures continue through Saturday, with highs in the single digits above and below zero and lows in the teens and 20s below zero.

- Another round of accumulating snow will impact areas mainly south and west of Lake Sakakawea and the Missouri River through Saturday morning.

- Temperatures are expected to warm to above normal for much of next work week.

UPDATE

Issued at 1149 PM CST Fri Dec 12 2025

Latest radar and observations show widespread snow falling across southwest ND late this evening. Otherwise, mainly high clouds across western and central ND with very cold temperatures and dangerous wind chills over northern and eastern portions of the forecast area. Updated text products will be transmitted shortly. Little changes needed to the going forecast.

UPDATE Issued at 1004 PM CST Fri Dec 12 2025

Snow has spread through much of southwest North Dakota, with snow increasing over the past hour or so in Dickinson. Snow amount forecast remains on track, but have bumped up chances through the southwest part of the state.

UPDATE Issued at 705 PM CST Fri Dec 12 2025

Snow has developed over southwest North Dakota in line with headlines that are in place. No changes needed at this time as will see how this system continues to evolve. Otherwise, frigid wind chills remain over areas with ongoing Cold Weather Advisory, with coldest readings below -30 remaining over northern portions of the area.

DISCUSSION

Issued at 251 PM CST Fri Dec 12 2025

This afternoon, a deep closed low was placed over Ontario, with broadly cyclonic flow aloft across much of the central and eastern CONUS. At the surface a stout Arctic high continued to expand into the Northern Plains from the southern Canadian Prairies, with a modest enough surface pressure gradient that gusty northwest winds have persisted into the afternoon longer than originally forecast. 20 UTC temperatures are generally around zero south to -10 F north, with wind chills anywhere from -15 to -35 F. A Cold Weather Advisory is in effect across northern and parts of central North Dakota.

A shortwave embedded in the northwest flow aloft is tracking along the southern edge of the surface high and a modest baroclinic zone, with a round of accumulating snow expected to move in later this afternoon and continue through tonight, with southwest North Dakota the primary area of accumulations. As the previous shift noted, there is some signal for potentially higher snow-liquid ratios, with forecast soundings advertising the bulk of the profile up to around 600mb within the dendritic growth zone, overlapping with modest omega. The HREF-based snowband probability tracker does not highlight any part of the forecast area for banded snow, which fits with deterministic and high-resolution guidance not advertising much low-level frontogenesis within the forecast area. This also fits with HREF chances for snowfall rates of at least 1 inch per hour being extremely low. Lapse rates, another needed ingredient for true banded snow, look marginal at best, although they do increase southwest of the forecast area. NBM probabilities for exceeding 6 inches of snow top out around 15 percent, so comfortable with the current headline. The Winter Weather Advisory for southwest North Dakota goes into effect early this evening and continues through Saturday morning, with a general 2 to 5 inches of snow expected and highest in the farthest southwest corner of the state. Forecast snow accumulations decrease to the north and east.

The Cold Weather Advisory continues through tonight, Saturday, and Saturday night, before ending Sunday morning. Air temperatures will be generally from -5 to -15 tonight, and -10 to -20 tomorrow night, with daytime highs on Saturday 5 degrees above zero to 5 degrees below zero. Very cold wind chills persist, approaching -40 F across northern North Dakota in the advisory area, but even across the southwest where we will see accumulating snow, wind chills will drop to around -20 which could prove dangerous if you have travel issues from the snow.

Snow will taper off through the morning Saturday as clouds slowly diminish from north to south, although still with those very cold temperatures as the Arctic high slides southeast. Deterministic guidance places the surface high in our favorable spot Saturday night that typically produces temperatures colder than forecast, although an impressive push of low-level warm air advection moving in from Montana could lead to temperatures tanking Saturday evening and early in the overnight period before moderating for much of the forecast area.

Confidence is high per ensemble and blended guidance on an upper level ridge building in to start next week, which will significantly boost temperatures across the state. Sunday will still have modest spread across the state as the warmer air filters in, with forecast highs from the lower 20s east to the upper 30s southwest, but we will then have high temperatures mainly in the lower 30s to lower 40s on Monday, and the widespread on 40s on Tuesday, with low NBM percentile spread showing strong agreement amongst ensemble members in this outcome. After Tuesday, uncertainty in the broad synoptic pattern increases as the ridge begins to weaken and shortwaves potentially move through, shown by blended POPs producing low to medium chances for precipitation on Wednesday. With the warmer temperatures aloft this introduces the potential for mixed precipitation, so this period will be one to watch for potential hazardous weather, as well as strong winds per the latest ECMWF EFI. CIPs Extended Analogs and CPC outlooks continue to favor a more active pattern across the region leading up to Christmas.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1149 PM CST Fri Dec 12 2025

IFR visibility and mainly MVFR ceilings in falling snow is expected to continue overnight and into early Saturday morning over southwest North Dakota. Otherwise, generally VFR ceilings and visibilities where snow is not falling. The northwest to south central could see periods of MVFR vsbys if snow pushes far enough north and east. Ceilings and vsbys will then improve through Saturday morning to VFR levels over the southwest. Mostly VFR cigs and vsbys expected elsewhere. Winds variable around 12 knots or less through the TAF period.

BIS WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory until 9 AM CST Sunday for NDZ001>005- 009>013-021>023-025-036-037. Winter Weather Advisory until 8 AM MST Saturday for NDZ031>033- 040-041-043-044.