235
FXUS63 KARX 030924
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
324 AM CST Wed Dec 3 2025

.KEY MESSAGES...

- Very cold temperatures are expected tonight and into Thursday
  morning with lows falling below zero areawide. Wind chills of
  10 to 25 degrees below zero are expected Thursday morning.
  Highs will likely only reach into the single digits to lower
  teens for Thursday.

- A weak system brings some snow chances (30-55% chance) for Saturday
  and Saturday night. However uncertainty still remains in the
  exact track of this disturbance.

&&

.DISCUSSION...
Issued at 324 AM CST Wed Dec 3 2025

Today - Thursday: Light Snow Exits, Much Colder Into Thursday

A surface cold frontal passage associated with a large upper-level
trough over Ontario will be the primary synoptic feature that will
dictate our conditions over the next 36-48 hours. Currently, pre-
frontal moisture and weak lift ahead of the cold front has initiated
some pockets of light snow across the area early this morning.
However, given the fast trajectory of the approaching cold front,
much of this should translate east of the local area by daybreak.
Overall accumulations will generally be minimal, on the order of a
trace to 1/2".

The larger story with this passing cold front will be the sharp cold
air advection it will bring along with it. As it passes through the
area this morning, temperatures will drop throughout the afternoon
and evening. As surface high pressure pushes into portions of the
Upper Midwest by the overnight hours, skies will likely clear out
with decreasing winds which will allow for efficient radiational
cooling. As a result, much of the NBM percentiles agree for
temperatures to fall below the 0 degree mark areawide tonight.
Additionally, some wind will remain with a weak surface pressure
gradient in place over the local area as the surface high centering
itself over central IA. Consequently, expecting wind chills by
Thursday morning to fall into the 10 to 25 below zero range, with
the coldest wind chills across unsheltered areas of southeast MN and
northeast IA. Cannot rule out La Crosse even seeing a record cold
low for Thursday morning as their daily record cold low for December
4th is -6F which was set back in 1893. Temperatures will not recover
all that substantially going into the afternoon with highs generally
progged to only reach into the single digits to lower teens above
zero with maximum wind chills still only in the single digits above
and below zero. Needless to say, make sure to wear multiple
layers when heading outdoors on Thursday.

Friday - Early Next Week: Colder Than Normal, Periodic Snow Chances

As we head into Friday, upper-level flow returns to slightly more
zonal allowing for warm air advection to push into the area and
returning highs back into the 20s for much of the local area. By the
weekend, the synoptic setup shows an upper-level trough situated in
Ontario, Canada to our east with our region subjected to quasi-zonal
to northwesterly flow. The main feature to watch will be a shortwave
that descends from western Canada and into the Great Plains during
the day on Saturday and into Saturday night. There still remains
great uncertainty as to where the exact track of this shortwave will
end up as cluster analysis of the grand ensemble (GEFS/EC/Canadian
ensemble) varies greatly. Currently, three scenarios seem to be in
play the first (roughly 20% of members) of which pushes the
shortwave squarely through our area due to the upper-level trough
being weaker with high probabilities (40-70% chance) for
accumulations of an inch or greater. The second and currently most
favored scenario with around 70% of members pushes the wave through
central IA and clips areas west of the Mississippi River with some
probabilities (20-50% chance) for one inch or greater of
accumulations. The last scenario which roughly 10% of members in the
grand ensemble show pushes the shortwave well to our south as the
upper-level trough in Ontario is much stronger and more amplified.
Regardless, very few members have any signal for amounts on the
order of 3" or greater so really not expecting an overly
impactful system, but certainly is our next shot for any
meaningful precipitation.

By next week, northwest flow re-establishes itself with guidance
keeping temperatures still slightly below normal into Monday with
highs likely remaining below the freezing mark. Deterministic
guidance in the GFS/EC/Canadian show various shortwave perturbations
that try to sneak into the area early next week. However, the
resolvability of any of these features remains low at this time. In
any case, would expect at least some periods of precipitation into
next week, but finer details remain unclear at this point.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1147 PM CST Tue Dec 2 2025

Light snow is overspreading areas along and north of a line
defined by the Iowa-Minnesota border with stations north of a
AEL-VOK line reporting at least sporadic snow over the past two
hours. Upstream visibility with this snow has generally be in
the 1 3/4 to 3 mile range so have gone with 2 mile mentions in
the RST/LSE TAFs for the next few hours. Once snow departs
around 12z some flurries may still occur at times through around
18z. Associated MVFR ceilings - generally in the 1-2kft range -
will be predominant as well through midday Wednesday. Skies
eventually trend toward clear during the last 6 hours of the
period.

&&

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

&&

$$

DISCUSSION...Naylor
AVIATION...Barendse/Ferguson