846
FXUS63 KBIS 020920
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
320 AM CST Tue Dec 2 2025

.KEY MESSAGES...

- Warmer temperatures, breezy conditions, and low to medium (10
  to 40 percent) chances for light snow showers today.

- An active weather pattern is forecast for the rest of this
  week, resulting in periodic low to medium chances for snow,
  breezy conditions, and moderate to large fluctuations in day-
  to-day temperatures.

- Very cold temperatures are forecast tonight into Wednesday
  morning and Wednesday night into Thursday morning, with wind
  chills possibly as low as 30 below zero.

&&

.DISCUSSION...
Issued at 320 AM CST Tue Dec 2 2025

Early this morning, broad cyclonic flow aloft due to a Hudson
Bay low dominated the synoptic pattern across the Northern
Plains, with a deepening surface low analyzed in south central
Saskatchewan. A warm front extended south of this surface low
and was placed north-south across western North Dakota, with
winds shifting to be westerly and much warmer air moving into
the area. Ahead of the warm front across central North Dakota,
temperatures were in the single digits above and below zero,
with the coldest area in the southern James River Valley along
the South Dakota border. Some light radar returns were ongoing
across our northernmost tier of counties, but higher ceilings in
this area are likely limiting any precipitation from making it
to the surface, at least for now.

The main weather concern in the near term is for fog and
subsequent reduced visibilities through the early morning, with
Harvey / Wells County the only area with any fog as of 08 UTC.
High-res guidance has been adamant on significantly reduced
visibilities across parts of the south central and southeast,
and there has been fog across the state line in north central
South Dakota, but that has yet to expand north.

Focus then turns to precipitation expected today and into
tonight as a shortwave moves across the region. Latest CAMs are
primarily emphasizing two areas of potential precipitation: one
in north central and northeast North Dakota, in line with an
upper level jet streak, and one in Montana and southwest North
Dakota, where the bulk of the forcing from the upper wave is
projected to track. This leaves the majority of the forecast
area in between these two areas, but opted to carry a broad 20
POP, with higher POPs across the north central and southwest.

We also cannot rule out a brief period of a wintry mix,
primarily in the northwest and west-central parts of the state,
as deterministic guidance is advertising a dry pocket and
potential loss of ice aloft. However, latest forecast soundings
have backed off this potential a bit, so would give this a low
probability outcome through the morning hours before expectation
would be for rain/snow p-types. Any snow accumulations should
be light and only a few tenths of new snow.

Breezy westerly winds are in the forecast as well today, with a
modestly tight surface pressure gradient. Typically that leads
to overperformance of forecast high temperatures, but with a
robust snowpack in place across the forecast area, opted to go
with the NBM 50th percentile for today`s highs. This puts
forecast highs in the mid 20s to mid 30s, with a short-lived
warmup behind the aforementioned warm front. The surface low`s
attendant cold front quickly drops south tonight, taking
overnight lows back into the single digits below zero (north)
and above zero (south). Arctic high pressure builds in on
Wednesday, helping partially clear skies out but keeping
temperatures mainly in the single digits for highs, and some
lower teens southwest. Apparent temperatures could be
approaching 30 degrees below zero both tonight and Wednesday
night.

Ensemble guidance is fairly conclusive on broad cyclonic flow
dominating the synoptic pattern through the rest of the week,
the weekend, and into next week. This means moderate to large
fluctuations in day-to-day temperatures and on and off chances
for precipitation that are relatively low predictability more
than a few days out. Temperatures moderate again for Thursday
and Friday as blended POPs are broadly 20 to 30 percent, with
deterministic guidance showing embedded shortwaves tracking
through the northwest flow. The more notable wave that has
potential to bring more than light accumulations arrives Friday
night through Saturday.

The varying solutions advertised by cluster analysis all show
accumulating snow during this period, increasing confidence in
the general expectation. Newest NBM guidance produces a general 20
to 40 percent chance of at least 2 inches of snow, with a 5 to
15 percent probability of at least 6 inches of snow. There`s
also modest agreement on both mid-level frontogenesis and
Q-vector convergence being present in the general area, which
would indicate banded snow potential, although we won`t be able
to resolve any details on this until much closer to the event.

There is high confidence on temperatures cooling down for the
weekend, although a large spread in NBM temperature percentiles
indicates there are still questions on how cold temperatures end
up. We`re then favored to moderate to near normal to start next
week, with a continued active pattern showing up in NBM
probabilities, CIPs extended analogs, and the CPC 6-10 and 8-14
day outlooks.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1217 AM CST Tue Dec 2 2025

VFR conditions at all terminals to start the 06Z TAF period.
Areas from around KBIS to KJMS could see low clouds or fog
develop overnight tonight, although too low of confidence in
occurrence and location to include with this update. MVFR
ceilings are forecast to develop from west to east during the
day Tuesday. There will also be low chances for light snow at
times, but again, too low of confidence to include any any
particular terminal for now. Light west to southwest winds
through tonight will become west to northwest on Tuesday around
15 knots, with some 25-30 knot gusts possible in the afternoon.

&&

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

&&

$$

DISCUSSION...Jones
AVIATION...Jones