562
FXUS63 KBIS 050722
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
122 AM CST Fri Dec 5 2025

.KEY MESSAGES...

- 1 to 4 inches of snow are possible tonight through Saturday
  with multiple small systems.

- Active weather pattern continues with near daily medium to
  high chances for snow over much of the area through next week.

- Temperatures remain near average for Friday, significantly
  cool this weekend, then gradually warm to start the next work
  week.

&&

.UPDATE...
Issued at 120 AM CST Fri Dec 5 2025

Snow continues to fall along and south of a line from Williston
to Jamestown. Automated surface observations also continue to
indicate some mixed phasing of hydrometeors, including freezing
drizzle. We have extended the mention of patchy freezing drizzle
through the night, and shifted it south in alignment with RAP
0-1 km RH fields. But snow remains the dominant precipitation
type in our forecast through Friday morning. CAMs do not appear
to have a good handle on the spatial extent and coverage of
accumulating snow, so current observations and trends were
heavily relied on for PoPs with this update. All other aspects
of the near-term forecast remain on track.

UPDATE
Issued at 945 PM CST Thu Dec 4 2025

The forecast for tonight remains on track. Main forecast change
was to add in some patchy freezing drizzle, based on ND DOT road
reports and an occasional mixed/unknown precip observation.
Overall, snow remains the dominate precip type, and we`re still
on track for a swath of 1-2 inches through sunrise Fri morning.

UPDATE
Issued at 628 PM CST Thu Dec 4 2025

Embedded wave/clipper system moving southeast into the Northern
Plains this evening, and will bring a swath of light
accumulating snow to much of western and central North Dakota
tonight, ending Friday morning after sunrise. 1-2 inches is
still looking good considering minimal forcing outside of the
wave itself and along the associated sfc trough axis. Initially
we are getting mixed precipitation reports where sfc
temperatures are at 32F or a tad warmer, though this has been
quickly changing over to snow via web cam imagery. RAP/HRRR
soundings do indicate a weak warm layer near the surface, and
not completely saturated. So does make sense that a brief mix
will be possible till we saturate and cool resulting quickly in
all snow.

&&

.DISCUSSION...
Issued at 200 PM CST Thu Dec 4 2025

Currently the Northern Plains are under northwest flow between a
large lower heights area in the Pacific Ocean, and another one
north of Maine. At the surface, a warm front is moving east
through the Dakotas and there is a cold front in southern Canada
aimed at North Dakota.

This evening the northwest flow through Montana will develop a
small wave off the Northern Rockies. This will then move through
the Dakotas tonight, along with a cold front out of Canada.
Pacific moisture embedded in the wave will meet up with the
dropping cold front over North Dakota. This front will create
strong frontogenesis (fgen) between northwest ND and southeast
ND. In turn this will create a banded snow event somewhere along
that diagonal line. Hi-res models are not in agreement fully on
where the axis of the highest snowfall will be. Some are off by
a county or 2 from the others. There will be some synoptic
driven factors as well like diverging Q vectors and steep lapse
rates around 8 degrees Celsius per km. The strongest diverging Q
vectors seems to be along the fgen or to the north. With all
these factors in mind we boosted the PoP chances from the NBM,
as well as used the QPF from WPC. We drew in a broad 40 percent
area along the fgen for now, and when we are more confident in
the snow band location it will be bumped up to likely (60+
percent). Timing looks like sunset in the northwest, expanding
south and east through the night and ending around 11am CT
Friday. A trace to 2 inches can be expected in this first round
tonight. The north central and far southwest may not get snow
at all.

Friday will be another warmer day with highs in the 20s and 30s.
Breezy winds could create blowing and drifting snow. Saturday
morning the next round of snow moves in from another small wave
creating a Northern Rockies low. This time the snow axis looks
more like the southwest part of the state. This will be a
familiar setup with a fgen band and steep lapse rates. Snow
amounts could be 1 to 2 inches in southwest ND and drop to just
a trace along the Missouri River. So across both systems 1 to 4
inches of snow are possible. This system will also bring in
much colder air, making morning lows well below freezing and
daytime highs in the single digits to teens through Sunday.

Next week northwest flow will still continue, this time with
near daily waves. This will create light snow chances most days
next week. The NBM already has likely (60%) chances in the
forecast. Temperatures will be mild across most of the state
with highs in the 20s and 30s. With those small quick moving
systems, breezy to windy winds are possible and maybe create
very low visibility.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 120 AM CST Fri Dec 5 2025

Snow will continue over most terminals, with some patchy
freezing drizzle possible at times north and east tonight.
Expect continued IFR to LIFR ceilings and visibility with the
snow. The snow will end Friday morning after sunrise, with
gradual improving ceiling conditions thereafter during the day
Friday.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...Hollan
DISCUSSION...Smith
AVIATION...NH