201
FXUS63 KARX 011810
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1210 PM CST Mon Dec 1 2025

.KEY MESSAGES...

- A period of light snow this afternoon and early evening will
  affect the area. Accumulations will be generally less than
  one-half of an inch, but further south in southwest Wisconsin
  an inch of snow is possible.

- Below normal temperatures are expected through the new week.
  The coldest temperatures are expected Thursday morning when
  subzero lows are likely (70-90%). Dangerously cold wind chills
  in the double digits below zero are possible, mainly west of
  the Mississippi River.

- Snow is possible again Wednesday (20-40%) and Saturday (10-30%).

&&

.DISCUSSION...
Issued at 404 AM CST Mon Dec 1 2025

Today

A positively titled trough over the central United States this
morning will quickly translate eastward throughout the day,
supporting snowfall potential across the Midwest. Modest low
level warm air and moisture advection this morning could support
periods of flurries ahead of the wave.

Stronger forcing associated with this wave moves in this
afternoon and evening as the left exit region of a 500hPa jet
streak overspreads the area over top weak positive vorticity
advection within the mean flow and the aforementioned low
level moistening. The strongest forcing remains to the south
over eastern Iowa into central Illinois, and a southward trend
of the highest precipitation probabilities is noted in the
01.00z HREF in response. However, modest forcing is still
expected to nudge over our far southern counties which is
anticipated to coincide with the DGZ which should promote
measurable snowfall. Overall, not much more than a light dusting
of snow is expected for most today with areas over southwest
Wisconsin receiving around 1 inch, but if the southern trend
continues, amounts will likely decrease.

Outside of the snowfall, high temperatures today top out in the
upper teens to low 20s with light southerly winds.

Below Normal Temperatures

Cold temperatures remain situated over the Upper Mississippi
River Valley through the week under primarily northwest flow
with highs generally 5-10 degrees below normal. Thursday is
expected to be the coldest day this week as strong cold air
advection moves in behind a cold front that traverses the region
on Wednesday. Confidence is high that temperatures will be
below zero areawide Thursday morning, as the 01.00z NBM
continues to depict subzero temperatures with a 25th-75th spread
of 5 degrees or less on average and the 90th percentile at or
below zero. Along with these temperatures, dangerously cold wind
chills are possible during this period with current apparent
temperatures in the double digits below zero. Those west of the
Mississippi River will see the coldest apparent temperatures,
with a 20-40% probability of falling below advisory criteria for
a time per the 01.00z LREF, primarily dependent on the strength
of the low level wind field and the timing of a low level ridge
axis moving into the region.

Additional Snowfall Through the Week

Active upper level flow is expected through the week with
several shortwave troughs traversing the region. These
shortwaves will be the catalyst of additional snowfall potential.

The first shortwave moves through on Wednesday, supporting the
aforementioned cold front. Moisture increases along the front
which combined with forcing from the front itself should support
some developing flurries to light snow (20-40%). Steepening low
level lapse rates reaching into the DGZ are possible in the
afternoon under diurnal heating and low level cold air
advection, which could act to support flurries through the
afternoon.

More appreciable snowfall is possible Saturday night through
Sunday, as another 500hPa shortwave trough sinks southward out
of Canada, promoting surface cyclogenesis over the Great Plains.
Confidence remains low with regard to how this period
ultimately plays out as 01.00z LREF cluster analysis paints
several scenarios regarding timing and location of these
features. However, this system could support impactful snowfall
across the area, so continues to be a period to monitor in the
coming days.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1208 PM CST Mon Dec 1 2025

A challenging forecast for aviation with widespread IFR-MVFR
cigs across the area and unorganized visibility in the IFR-
MVFR range. A weather disturbance is bringing afternoon light
snow to the area.

The latest satellite and surface observations at 18Z show some
drying in the very lower levels working into southeast MN from
the west. This drying isnt going to make it too far east it
would appear, but has just arrived in KRST for a reprieve from
IFR cigs. This may hold until the overnight when ceiling
lowering is again expected but confidence is lower in this
forecast.

Visibilities in the snow have generally been lowering to MVFR and
radar indicates the snow becoming a bit more widespread. There
are pockets of IFR snow near 2SM now. This should continue to
shift east and southeast this afternoon, ending from the
northwest during late afternoon and evening.

&&

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

&&

$$

DISCUSSION...Falkinham
AVIATION...Baumgardt