980
FXUS63 KARX 012331
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
531 PM CST Mon Dec 1 2025

.KEY MESSAGES...

- Some light snow accumulations from this afternoon into the
  early evening and from Tuesday night into Wednesday morning.
  Snow accumulations of a trace to around a half-inch.

- Very cold from Wednesday night into Thursday night. Wind
  chills of 10 to 25 below during the overnights and early
  mornings.

- Another round of potential snow from Saturday into Saturday
  night. Lots of uncertainties on the track of this system.

&&

.DISCUSSION...
Issued at 145 PM CST Mon Dec 1 2025

This Afternoon and Evening

A longwave trough will move southeast through southeast Minnesota,
Wisconsin, eastern Iowa, and Illinois. While the best synoptic
forcing and 850 mb moisture transport will remain just south and
east, there is enough lift from 700 to 300 mb for some light
snow. Up to 100 mb of the sounding profile is located in
dendritic growth zone. This will aid in helping to produce some
light snow accumulations. Snow amounts will likely range from a
trace to a few tenths of an inch. After the passage of this
trough, the forcing quickly wanes.

Tuesday Night into Wednesday Morning

Another longwave trough will move southeast through the area.
Like the system today, there is about 100 mb located in the
dendritic growth zone. This will aid increasing the snow to
liquid ratios close to the 13 to 1 snow to liquid ratio
climatology. With many of the models showing anywhere from a
trace to 0.3" of liquid. As a result expecting snow totals
ranging from a trace to a half-inch.

Wednesday Night into Thursday Night

Arctic air will be located over the region. Low temperatures on
Wednesday night will be mainly in the single digits below zero.
Highs on Thursday will range from 5 to 15 above. Low
temperatures on Thursday night be range from around 0 to 5
above. Wind chills during the overnights and early mornings may
range from 10 to 25 below.

Saturday into Saturday Night

The models are in good agreement that yet another shortwave
trough will move southeast through the region. This one looks to
be stronger than its predecessors. Still plenty of spread in the
models from this system moving southeast across northern and
eastern Wisconsin and then southeast into the southern Great
Lakes to others which have this system remaining to our
west and south. The 01.12z operational models have been trending
more toward the western portion of model solution envelope.
Looking at the Grand Ensemble up to 15% of the members have snow
totals in the excess of 3 inches.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 525 PM CST Mon Dec 1 2025

A range of VFR to IFR conditions are currently present across
the Upper Mississippi Valley this evening. MVFR to IFR CIGs are
expected to build back in across the area but there is low
confidence in when exactly this will occur with hi-res models
struggling to initialize the near-term properly. A deck of IFR
to low-end MVFR stratus currently sits over NE Iowa and is
progged to expand north and east through the overnight hours.
Amendments to the arrival time of the lower CIGs will likely be
needed in the short term using observational and satellite
trends. Model soundings for RST seem to indicate deep enough mixing
below the inversion to prevent LIFR CIGs from developing so have
upped CIGs slightly from the previous package. Once the lower
CIGs arrive, they should linger through tomorrow morning before
lifting to VFR generally after 18Z. Winds overnight will remain
light out of the south at less than 10 kts, picking up to
between 8-12 kts by late tomorrow morning.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.

&&

$$

DISCUSSION...Boyne
AVIATION...Barendse