757
FXUS63 KFGF 172130
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
330 PM CST Wed Dec 17 2025

.KEY MESSAGES...

- Blizzard conditions will impact much of the Red River Valley
  and points west Thursday. Falling snow elsewhere will combine
  with gusty winds to reduce visibility on a more periodic
  basis.

- Widespread travel impacts are expected across much of eastern
  North Dakota and parts of northwest Minnesota Thursday.
  Dangerously cold wind chills along and north of US Highway 2,
  combined with blizzard conditions, will lead to potentially
  life-threatening travel conditions.

- High winds will develop across the Red River Valley and west.
  Sustained northwest winds of 40 mph are expected, with
  occasional gusts up to 70 mph.

&&

.DISCUSSION...
Issued at 131 PM CST Wed Dec 17 2025

...Synopsis...

Surface analysis this afternoon indicates the center of the
upcoming storm low over southeastern Alberta crossing into
Saskatchewan. A very broad warm front is attached to it and is
contributing to ongoing isentropic ascent across the
international border. Sounding analysis indicates that the lift
appears to be centered in a dry layer between 925 and 700 mb, so
there have been sparse observations of precipitation making it
to the surface. Having said that, freezing rain was observed up
in Winnipeg and a few flakes have mixed in. Surface analyses
indicate subfreezing temperatures ongoing and with max wet bulb
temperatures above 0C, freezing rain remains a possibility this
afternoon. Close monitoring will be necessary through the
afternoon hours for potential freezing rain.

As we progress into the evening and overnight hours, the surface
low will begin to approach from the west. The central pressure
is expected to rapidly deepen in the lee of the Rocky Mountains,
forcing baroclinicity to increase with the low. Pacific moisture
and weak gulf moisture return will facilitate widespread light
snow across the region with very strong winds associated with
the low. Major travel impacts are expected to begin around
midnight to early morning, generally peaking mid-morning, and
slowly beginning to taper off thereafter.

On the backside of this Winter Storm, another swath of light
snow can be expected Friday, although lack of winds should limit
impacts to areas of blowing snow. Travel may become hazardous
but is not expected to become dangerous quite like tomorrow.

...MAJOR WINTER STORM...

Surface analysis this afternoon indicates the central pressure
sits around 977mb and is centered in southeastern Alberta and
will cross into Saskatchewan in the next hour. Temperature
observations indicate a healthy developing extratropical cyclone
with intensifying cold air advection west of the central low.
As we progress into the evening, the low will continue to
approach from the west. As this occurs, isentropic ascent will
increase and will continue to warm near surface temperatures. As
a result, a swath of rain is expected across the region
beginning this evening and lasting towards midnight. Eventually,
a brief break will occur as the main isentropic ascent
propagates eastward, giving a brief break from precipitation
before the main impacts arrive.

As the cold front approaches, high resolution guidance has keyed
off of the strong instability in the lowest 1 km of the
atmosphere. While most guidance keeps the strongest
frontogenesis to our south, there have been a few members that
have output snow squalls. Should we see a snow squall, the most
likely impact timeframe would be between 3 AM and 9 AM and would
most likely impact southeast North Dakota into west-central
Minnesota. Impacts from a snow squall would be a very quick drop
in visibility from clear to whiteout, followed by a rapid
increase in winds. Given instability, strength of the low-level
jet and cold air advection, and strong frontogenesis, snow
squalls do appear possible somewhere within the northern plains,
with the bulk of guidance keeping it to the south of our area.
Be prepared for alternate travel plans should a Snow Squall
Warning be issued.

Pretty much everything with this system surrounding winds will
be going right to make for a high wind event. We start with the
pressure gradient force component of surface winds. As stated
above, this system has rapidly deepened over the last several
hours and is down to sub-980 already. This should remain fairly
steady state as it approaches. Behind the low is roughly a
1018mb high pressure system so as this event is ongoing, we will
have a very tight pressure gradient. This means pressure rises
will at least exceed 4mb/hr, with some guidance pushing
5-6mb/hr. This means that the low pressure alone will produce
strong northwesterly winds, at least sustained to 40 mph or
greater in the High Wind Warning area. To add to this background
environment, strong quasi-geostrophic descent associated with
the cold air advection and differential advection patterns at
the surface and aloft will allow for steepening lapse rates.
This means vertical mixing is also in play to assist strong
winds and provide gusts approaching 50-60 mph at times. Putting
both of those together, we also have the perfect wind direction
to access stronger winds within the Red River Valley,
intensifying both sustained winds and wind gusts. This is why
there is the low potential to exceed 60 mph at times with wind
gusts. The general ceiling based on all of these ingredients
places the ceiling for winds around 65-70 mph, but most should
remain closer to the 55-60 mph gust range at its highest. All of
these ingredients will be mainly over the Red River Valley and
west. East of the Red River Valley, sustained winds will be
elevated, but without the strong pressure rises and strong cold
air advection, gusts will be much less and generally around
35-50 mph.

The strong winds above, coupled with the intensifying cold air
from the north coming through as the front pushes eastward, will
create dangerous wind chill conditions along and north of US
Highway 2 where winds will be strongest and temperatures
coldest. While air temperatures will be fairly climatologically
normal for this time of year, the strength of winds will drive
wind chills down to the -30s and potentially getting below 40
closer to the international border. Dangerous wind chills will
be solely associated with strong winds through the day tomorrow,
so once winds diminish towards Thursday, wind chills should no
longer be an issue.

Now we get to the main story: the blizzard. We have the winds,
we have the cold, we just need the snow. The main problem is we
have been well above freezing yesterday and today, but this
system brings the solution in additional snow. Now with falling
snow, plus the wind, plus the cold, there will be more than
enough to create whiteout conditions. But how long will it last?
Well it depends on where you are. For a blizzard to develop, you
need one of the two conditions:

1.) Falling snow.

2.) 2 inches of blowable snow on the ground.

Problem #1: Falling snow is likely across pretty much the entire
area. Anywhere where there is falling snow and high winds exist
(which is the Red River Valley and west), whiteout conditions
will develop. Further east, falling snow will contribute to
dangerous travel conditions, but is unlikely to create sustained
blowing snow impacts due to limitations on wind in sheltered
areas.

Problem #2: Blowing snow of at least 2 inches does not exist in
our area right now. Warm temperatures have contributed to pretty
much torching our entire snowpack to make it very hard to
impossible to blow. So what we need is at least 2 inches on the
ground to create blowable snow. Where this is likely to occur is
across northeast North Dakota and northwest Minnesota,
increasing the further north you get. As stated above, the winds
will be strongest in the Red River Valley and west, so the
overlap will be along and north of US Highway 2 within the
Blizzard Warning area. Within this location, blizzard conditions
will be prolonged because adding on the blowing snow component
will allow for whiteout to continue without falling snow. This
means whiteout conditions will likely linger into Thursday
afternoon, whereas south where it is very unlikely 2 inches will
be observed will experience rapid improvements absent falling
snow.

Combining both the blowing snow and falling snow, the longest
duration blizzard conditions will be felt along and west of the
Red River Valley and along and north of US Highway 2 (drawing a
rectangle around those two endpoints up to the international
border). Combine that with the dangerous cold that will develop,
life threatening conditions will arise in this region,
particularly as you get closer to the international border where
snowfall amounts will be heaviest and coldest wind chills will
be observed.

Even with this, however, travel will be impossible within the
Blizzard Warning area and it is mainly a question of how long it
lasts, which will depend on duration of falling snow and amount
of blowable snow. Regardless of these uncertainties, evaluate
travel plans and be prepared for dangerous conditions.

Even with all the uncertainties, this system will exit the
region late Thursday afternoon and early evening, and conditions
will improve by 9 PM at the latest.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1107 AM CST Wed Dec 17 2025

VFR conditions will prevail for the first 6 hours of the TAF
period with gusty southerly winds through the day today. A
strong low level jet will develop and cause wind shear this
afternoon from the southwest, eventually becoming westerly
through the evening.

Rain will shift east through the evening and overnight hours,
with winds eventually becoming westerly behind it. This will
coincide with a reduction in ceilings to MVFR/IFR across much of
the region.

A brief break in precipitation should coincide with a brief rise
to high end MVFR to VFR conditions. However, conditions will
rapidly deteriorate after this break. Snow and very strong
northwesterly winds will develop across the region. GFK/FAR/DVL
are likely to see gusts exceeding 50 knots at times, with weaker
but still strong gusts exceeding 40 knots expected further east.
Snow will accompany these strong winds to create 1/4SM
prevailing visibilities at FAR/GFK/TVF/DVL with MVFR to IFR
visibilities expected also at BJI. This will last through the
end of the TAF period alongside widespread IFR ceilings (to
possibly LIFR as well).

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Blizzard Warning from 3 AM to 6 PM CST Thursday for NDZ008-016-
     026>030-038-039-054.
     Cold Weather Advisory from 6 AM to 6 PM CST Thursday for
     NDZ006>008-014>016-026-027-030-054.
     High Wind Warning from 3 AM to 6 PM CST Thursday for NDZ049-
     052-053.
     Winter Weather Advisory from 3 AM to 6 PM CST Thursday for
     NDZ049-052-053.
     Blizzard Warning from midnight tonight to 6 PM CST Thursday
     for NDZ006-007-014-015-024.
MN...Blizzard Warning from 3 AM to 6 PM CST Thursday for MNZ001>005-
     007-008-013>015.
     Cold Weather Advisory from 6 AM to 6 PM CST Thursday for
     MNZ001-002-004-005-007-008-013>015.
     Winter Storm Warning from 6 AM to 6 PM CST Thursday for MNZ006-
     009.
     Winter Weather Advisory from 6 AM to 6 PM CST Thursday for
     MNZ016-017-022>024-027-028-030>032-040.
     High Wind Warning from 3 AM to 6 PM CST Thursday for MNZ029.
     Winter Weather Advisory from 3 AM to 6 PM CST Thursday for
     MNZ029.

&&

$$

DISCUSSION...Perroux
AVIATION...Perroux