188
FXUS63 KARX 022312
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
512 PM CST Tue Dec 2 2025

.KEY MESSAGES...

- Light snow chances (20 to 45%) tonight into Wednesday
  morning. Snow accumulations of a trace to 1/2" possible.

- Very cold Wednesday night into Thursday with wind chills of
  10 to 25 degrees below zero Thursday morning. High
  temperatures for Thursday remaining in the low teens.

- Additional snowfall chances Friday through early next week.

&&

.DISCUSSION...
Issued at 126 PM CST Tue Dec 2 2025

Today-Thursday: Light Snow Tonight, Very Cold Thursday

Today will be a quiet and mostly cloudy day. Heading into tonight, a
cold front moves through the region and while the forcing with the
front is not expected to be impressive, the low level saturation
already in the area will help to produce light snow. The timing for
this snow is roughly between 03 and 13Z tonight. HREF probability of
measurable snowfall compared to the previous forecast has about the
same 30 to 65% chance for measurable snowfall for most locations
outside of northeast Iowa and far southwest Wisconsin. The total
accumulations from this light snow will mostly be a few tenths with
some locations potentially seeing up to 0.5". With this snow,
the morning commute may be impacted as snow covered roads will
be possible especially on untreated roads.

After this snow leaves the area, colder air will filter in behind
the cold front. Wednesday is looking like one of those days where
the "warmest" part of the day will be in the morning where
temperatures are expected to be in the 20s. As the cold air moves
in, temperatures dip down into the teens for most locations by the
evening with some areas in the western and northern portions of the
CWA getting down into the single digits. Once the evening rolls
around, skies begin to clear up as a surface high moves overhead.
Radiational cooling will help to lower temperatures rather
efficiently Wednesday night into Thursday morning. Low temperatures
for Wednesday night/Thursday morning are currently forecasted to
range from -5 to -10F. With snow on the ground and combined with the
clearing skies, these temperatures could end up being slightly
colder. To put into perspective how cold this will be for this time
of year, the EFI values for Wednesday night/Thursday morning are
between -0.7 to -0.9 which indicates these temperatures are on the
lower side of climatology for this time of year.

As the aforementioned surface high moves into central Iowa,
northwest winds gradually diminish by Thursday morning, but since we
would be on the northern end of the surface high, a pressure
gradient remains over the area, causing northwest winds around 10mph
during the overnight to be possible. These winds will create wind
chills in the -10 to -25F. One thing to note is that depending on
how far south the surface high goes will determine our wind speeds
overnight. If the high goes slightly further south, this could
increase winds slightly, making the wind chills a little colder.
While Thursday will bring some warm air advection to the region via
southwesterly winds, it will be very weak and only help to increase
high temperatures into the low to mid teens.

Friday-Monday: More Snow Chances

As we head towards the end of the week, there looks to be a few
chances at snow. The first chance is associated with a shortwave
that moves through the Great Lakes on Friday morning. The best
chance for light snow remains along and north of I-94, however this
shortwave will bring a cold front with it during the afternoon but
the surface front does not come through until later Friday night.
GFS and NAM soundings for Friday do show the northwest aloft with
low level saturation and as a result, light snow showers look to be
possible during the morning and afternoon for much of the CWA.

The next timeframe to look for potential impactful snow is Saturday
night into Sunday as another shortwave trough dips down into the
Plains. There still remain a bit of uncertainty as the deterministic
GFS keeps this in Nebraska and Iowa whereas the ECMWF is further
north in southern Minnesota and Iowa. Comparing these to LREF (GEFS/
cluster analysis about 70% of ensemble members continue to show the
longwave trough to the north not being as deep compared to the other
30%. This means that the shortwave trough won`t dip down into the
central Plains as much and impact more of the Upper Midwest. When
looking at the probability for at least 1" of snow, the members that
have the shortwave further north have a 30 to 50% chance across much
of the CWA. The solution with the shortwave dipping further south
would mean northeast Iowa has the best chance at seeing at least 1"
(30 to 40%). Another weak shortwave passes through on Monday ahead
of a stronger shortwave that will increase light snow chance for the
day on Monday.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 510 PM CST Tue Dec 2 2025

MVFR to VFR conditions currently present across the region early
this evening. A batch of MVFR/IFR stratus and some light snow is
expected to move into the area ahead of an approaching cold
front to our northwest. Snow will likely cause some minor
categorical reductions but they shouldn`t go below high-end IFR,
mainly for areas along and east of the Mississippi River. This
should move out late overnight with only some light flurries
possible by daybreak for the terminals. Ceilings should begin to
scatter out and return to VFR during the late morning/early
afternoon. Southerly winds early in the period will begin to
veer to the northwest after midnight as the front moves through
the area. Wind speeds will increase to between 10-15 kts around
daybreak with some higher gusts possible through the afternoon.

&&

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

&&

$$

DISCUSSION...Cecava
AVIATION...Barendse