437
FXUS63 KFGF 050530
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1130 PM CST Tue Feb 4 2025

.KEY MESSAGES...

- Snow accumulations of 1-3 inches are likely in eastern North
  Dakota towards north central Minnesota Wednesday into
  Wednesday night bringing the chance for minor impacts to
  travel.

- Chance for hazardous travel conditions Thursday afternoon and
  evening for eastern North Dakota and portions of northwestern
  Minnesota due to blowing/drifting snow.

&&

.UPDATE...
Issued at 944 PM CST Tue Feb 4 2025

Cloud cover has continued to increase, especially along the
south. Still haven`t seen much in the way of reports of snow, so
for now don`t expect snow through noon. Expect snow to begin
after noon, overspreading much of northwest Minnesota by the
evening.

UPDATE
Issued at 636 PM CST Tue Feb 4 2025

Sky cover remains the only real thing going on. Based on
observations, it appears that most of the echoes on radar are
not making it to the surface, although there is the low chance
for some to make it in the Devils Lake Basin. No accumulations
can be expected from snow this evening and impacts will be
limited to almost nonexistent.

&&

.DISCUSSION...
Issued at 221 PM CST Tue Feb 4 2025

...Synopsis...

Quiet conditions are expected throughout today as a broken cloud
deck moves through the northern plains. Temperatures will be in the
negative single digits to single digits for high temperatures. Weak
winds have helped keep apparent temperatures from reaching advisory
level criteria. Thus we don`t expect a cold weather advisory this
evening and tonight.

Split flow continues to dominate across North America. Southwesterly
flow extends across the southwestern United States through the
central plains and northwesterly flow over the Canadian prairies
through the Great Lakes. Out of these flows we have several chances
for potential impactful weather across the northern plains. First
moves out of the northwesterly flow Wednesday through Thursday and a
secondary system moves through over the weekend. Temperatures will
be in the single digits to lower teens through this period, with a
push of CAA bringing temperatures below zero for daytime highs post
next weekend. The first system tracks along the International Border
bringing the chance for accumulating snow Wednesday into Wednesday
night. Weak cold air advection wraps around the system Thursday
afternoon, with daytime mixing. Confidence is on the lower end with
regards to the blowability of the snowpack. These are key to the
impact level of the blowing/drifting snow. Confidence is increasing
in the secondary system being driven by frontogentic forcing, but
this lowers the confidence in placement and snowfall amounts.

...Accumulating snow Wednesday...

A open wave shifts through southern Canada Wednesday bringing the
chance for accumulating snow to the area. Main driver of
precipitation is synoptic with the strongest forcing along and north
of the International Border. Widespread snowfall is expected, with
the heaviest north of the International Border and further into the
Arrowhead of MN where the main open wave system tracks. Probabilities
of seeing over 2 inches being 60-80% along the International Border
and into north central MN. Any frontogentic forcing remains north of
the border limiting any banding potential within our area.
Probabilities of seeing over an inch are 40-60% for the Sheyenne River
Valley, Devils Lake Basin, and wet central MN. There is a 60% chance
for minor impacts to travel for areas around Lake of the Woods and
along the International Border due to accumulating snow.
Precipitation exists the area late Wednesday night, with winds
switching toward the WNW.

...Blowing and drifting snow Thursday...

Recent reports from observers near the Devils Lake Basin into
northeastern North Dakota indicate some of the snowpack is still
blowable even with the lighter winds today. Winds are expected to
increase as the system Wednesday shifts away from our area. Guidance
continues to show weak CAA on the back edge of the system Thursday.
The strongest winds will be tied to the daytime mixing in the lower
levels during the afternoon and evening on Thursday. Uncertainty
arises with the amount of snowpack that is blowable, snowfall from
Wednesday, and if we can mix and get higher winds. Three types of
scenarios are on the table for what may occur during this time on
Thursday.

The first scenario (60% chance) would indicate weaker WNW winds on
Thursday as mixing is limited thanks to the weak CAA and orientation
of the low level winds. Snow is blowable from the recent snow and
the old snowpack. This would result in minor impacts to the area and
near advisory criteria for portions of eastern ND and northwestern
MN. The second scenario (20% chance) would be, we are able to mix
down the higher winds aloft of 35-40mph. This combined with snowpack
and recent snow fall would cultivate in widespread blowing snow and
reductions in visibility down to a quarter of a mile or less
(especially in open country). The last scenario (20% chance) is
weaker winds in the low levels combined with a lack of blowability
of snowpack resulting in heightened impacts to travel. An SPS was
issued to bring awareness to the potential of wintry impacts.

After the system on Thursday, we have a brief break in activity
before another system starts to shift in from the south bringing
stronger frontogentic forcing to areas along and south of I-94. It`s
still to early to determine the severity of impacts from
accumulating snow as guidance struggles with the track of the
frontogentic forcing which drives the potential banding and heaviest
portion of the snowfall. Stronger forcing and longer residence time
would lead to heavier snowfall rates and thus higher accumulations.
As of right now probabilities of over 2 inches are 60-70% along and
south of I-94.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1130 PM CST Tue Feb 4 2025

For the most part, expect VFR conditions but ceilings will begin
slowly lowering through the overnight. MVFR ceilings may make it to
FAR before 12z, but confidence is very low in this regard.
Conditions will slowly deteriorate to MVFR by the late afternoon as
snow arrives and ceilings lower. Isolated IFR to LIFR can be
expected as well, although confidence in where this occurs is low.
Once snow develops, expect MVFR to IFR conditions to continue
through the remainder of the TAF period, with the clearing beginning
from west to east closer to 06z. Winds will shift to westerly by
then with a sharp increase in wind speeds, bringing the potential
for blowing snow to keep visibilities below VFR.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.

&&

$$

UPDATE...Perroux
DISCUSSION...Spender
AVIATION...Perroux