283
FXUS63 KBIS 090448
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1048 PM CST Mon Dec 8 2025

.KEY MESSAGES...

- Freezing rain will impact most of western and central North
  Dakota late tonight and Tuesday morning, with ice
  accumulations as high as one tenth of an inch.

- Very strong winds expected late Tuesday morning through
  Tuesday night, with gusts as high as 65 mph.

- 1 to 4 inches of snow are expected in the Turtle Mountains
  area Tuesday morning through Tuesday night.

- Another round of snow will impact all of western and central
  North Dakota Wednesday afternoon through Thursday night.

- Below average temperatures are expected Wednesday through the
  upcoming weekend, with dangerous wind chills possible Thursday
  evening through Saturday morning.

&&

.UPDATE...
Issued at 1047 PM CST Mon Dec 8 2025

Quick update to add patchy to areas of fog to the forecast over
central ND through about 10 UTC based on observed trends which
have fog developing on the edge of a stratus deck. This is no
doubt aided by boundary layer moisture enhancement resulting
from above-freezing temperatures over the snowpack today, and
from the relatively sharp low-level inversion that`s in place.

UPDATE
Issued at 1005 PM CST Mon Dec 8 2025

Given the consensus of recent CAMs and other incoming 00 UTC
model suites, we delayed the start time of the Winter Weather
Advisory in western ND slightly until 1 am CST, and longer in
central ND until 4 am CST. This was done in order to convey that
impacts will not begin until later in the night, but we need to
emphasize that once precipitation begins to develop, guidance
suggests it will do so quickly, with increasing impacts quickly
to follow. Forecast soundings suggest top-down saturation will
only take 1-2 hours once low- and midlevel ascent arrives in any
given location, and thermal profiles continue to display the
requisite configuration for freezing rain with a warm nose
aloft on the order of +3 to + 6 C atop a shallow, subfreezing
surface layer. The 00z KABR RAOB reflected this thermal profile
already, too. Note that surface temperatures are still expected
to also warm above freezing from west to east Tuesday morning,
but there is apt to be a lag between when surface temperatures
exceed 32 F and when ground conditions warm above that
threshold. We held off adding any of the remainder of far
southwest ND to the Winter Weather Advisory with this update,
since recent guidance suggests the greatest precipitation will
be east of that area, but trends will be monitored closely in
case a short-fuse expansion is needed. Otherwise, we updated
hourly forecast fields with this update based on recent rapid-
refresh model guidance. The overall forecast theme underwent
only minor changes in timing, but we did increase precipitation
chances into the 80-100 percent range over more of the area
Tuesday morning.

UPDATE
Issued at 635 PM CST Mon Dec 8 2025

Little change is needed to the forecast, and there were no
changes to the Winter Weather Advisory and High Wind Warning
with this update. As of early evening, a weak surface low is
near Devils Lake and moving southeast out of the area. The
midlevel air mass west and southwest of that system is very
warm, with the 18z KBIS RAOB having already sampled a warm nose
aloft that was around +3 C in the 900 to 850 mb layer. That will
set the stage for freezing rain late tonight and Tuesday morning
as forcing for ascent increases as a low- and midlevel warm front
tied to a rapidly-deepening surface low in southern Canada and
an associated intense jet streak aloft move across western and
central ND. The 18 UTC global model guidance and recent rapid-
refresh guidance remains in agreement on this scenario, so no
changes were needed to our messaging at this time. We will need
to carefully consider whether the rest of southwestern ND not
already in a Winter Weather Advisory will need one for freezing
rain for a few hours late tonight and Tuesday morning, but that
area will be closest to the surface freezing line when
precipitation develops. Otherwise, the incipient surface low
with the upcoming system is in west central Alberta as of this
writing, with water vapor imagery suggesting the intensifying
upper-level jet streak that will foster its rapid strengthening
the next 12 hours beginning to spread east across the Rockies.

&&

.DISCUSSION...
Issued at 315 PM CST Mon Dec 8 2025

Currently northwest flow is over the Northern Plains. At the
surface a warm front has moved east through North Dakota. Colder
air sits in southern Canada awaiting to be pulled into the
state by the backside of the low pressure system moving in
tonight. Across western ND temperatures are above freezing post
warm front, with breezy west winds. An Atmospheric River from
the Pacific Ocean is flowing over the Northern Rockies creating
a large high cloud shield over Montana and North Dakota.

The Storm:

Tonight an Alberta Clipper will start to move into the Northern
Plains, tapping into that Pacific Ocean moisture. With the
current northwest flow, there is warm air aloft ahead of the low
across eastern Montana and North Dakota. This will create a
swath of freezing rain as surface temperatures will be below
freezing, moving west to east early Tuesday morning through
about noon CST. A Winter Weather Advisory has been issued for
this threat across most of western and central ND. We left the
far southwest out because most of the precip will be farther
north and east. If you are traveling to work in the morning be
sure to check the road conditions.

As the low moves through ND, and surface temperatures warm
above freezing, it will switch to rain and the Winter Weather
Advisory will expire at noon CST. The Turtle Mountains will be
cooler and remain in the cold sector of the low, so mainly snow
is expected. Current forecast totals are 1-4 inches with
locally heavier amounts as you get closer to Canada and farther
east into Towner County. The Winter Weather Advisory will remain
there all day. QPF amounts are anywhere from 0.10 to 0.20 for
the west and central. Closer to the northeast and east (the
bullseye of the system) the amounts increase to 0.30 inches. A
lot more snow will fall in the eastern part of the state where
the cold sector and very strong frontogenesis with high lapse
rates are located. Northeast ND will also be the left exit
region of the jet stream, enhancing the lift and strength of the
system. All that to say, snow amounts will be limited in our
CWA by the length of time in the warm sector and lack of
forcing. There will be a lull in precip in the afternoon before
the wrap around moisture moves in from the north in the
evening. This wrap around will mainly be snow, especially after
sunset and through the overnight. Snow accumulations from
Tuesday night will likely be below 1 inch and be limited to the
Highway 52 corridor.

For the winds, the pressure gradient will tighten in the late
morning and combine forces with cold air advection (CAA) on the
backside of the low. A strong pressure bubble will also be with
the CAA, creating winds up to 65mph, possibly 70mph at times.
We have a High Wind Warning out that will replace the Winter
Weather Advisory at noon CST. The far southwest`s Warning will
start a tad earlier at 8am MST. The strong winds will reside
Tuesday night, but breezy winds will continue through Wednesday
morning. Blowing snow is also a concern but may be limited if
the freezing rain puts a crust on the snow or if the rain soaks
the snow enough to be too wet to be lofted. Likely either way
there will be plenty of drifting snow across the roads
Tuesday afternoon through the overnight.

Rest of the week:

Wednesday a Northern Rockies low will form and move through the
state, bringing the next round of snow. Models continue showing
strong frontogenesis setting up in a northwest to southeast
diagonal across ND with jet stream support. Calibrated NBM
probabilities for 1 inch of snow range from 20 to 50 percent.
The higher chances are in the southwest where the frontogenesis
may linger longer. Winds will not be as strong as Tuesday, only
around 20mph. High temperatures will also be much cooler in the
single digits in the northeast to the low 30s in the southwest
(no snow pack). This snow system will linger into Friday.

Northwest flow will then continue through the weekend, with
very cold Arctic air dropping into the state. Lows starting
Friday morning will be in the negatives statewide. Expect lows
around 15 below in the north and 5 below in the south. This will
make wind chill values of -25 to -40 across the state. This
will need a Cold Weather product later this week. Saturday
morning will be similar and Sunday morning will be slightly
warmer but will still have wind chills around -20. In the
northwest flow through the weekend, small waves will form off
the Rocky Mountains, bringing low to medium (20-40%) chances of
snow to North Dakota.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 1005 PM CST Mon Dec 8 2025

High-impact weather for aviation interests is expected across
western and central ND during the 00 UTC TAF cycle and beyond.
Initially, an area of IFR to MVFR ceilings in north central and
east central ND will impact the KJMS terminal until late
tonight. However, the main impacts from the upcoming Alberta
Clipper passage will begin in western ND in the 07-10 UTC time
frame when rain and freezing rain is expected to develop.
Freezing rain is forecast to move into central ND in the 10 to
13 UTC time frame. Expect a few hours of freezing rain at most
if not all terminals in western and central ND late tonight and
Tuesday morning, before temperatures rise above freezing,
turning precipitation to rain. MVFR to IFR ceilings will also
occur late tonight and Tuesday. Precipitation will generally
diminish from west to east during the day Tuesday. Low-level
wind shear will develop late tonight and Tuesday as well, with
westerly winds of 45 to 55 kt as low as 1500 AGL. Strong
westerly surface winds will also develop from Tuesday morning
into the early afternoon, before increasing further and turning
more northwest, with peak gusts to around 50 kt Tuesday
afternoon and Tuesday evening.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon CST /11 AM MST/ Tuesday for
NDZ001-002-009-010-017-018-033-041-044.
High Wind Warning from noon CST /11 AM MST/ to 9 PM CST /8 PM
MST/ Tuesday for NDZ001>003-009>012-017>021.
Winter Weather Advisory from 4 AM CST /3 AM MST/ to noon CST
/11 AM MST/ Tuesday for NDZ003-011-012-019>023-025-034>037-042-
045>048-050-051.
Winter Weather Advisory from 4 AM Tuesday to midnight CST
Tuesday night for NDZ004-005-013.
High Wind Warning from noon CST /11 AM MST/ Tuesday to 3 AM
CST /2 AM MST/ Wednesday for NDZ022-023-025-033>037-041-042-
044>048-050-051.
High Wind Warning from 8 AM to 8 PM MST Tuesday for NDZ031-032-
040-043.

&&

$$

UPDATE...CJS
DISCUSSION...Smith
AVIATION...CJS