281
FXUS63 KARX 251945
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
145 PM CST Tue Nov 25 2025

.KEY MESSAGES...

- Rain changes to snow tonight and persists into Wednesday
  morning resulting in accumulating snow for the local area.
  Highest accumulations will likely be generally near and north
  of I-90 where anywhere from 1 to 4 inches may fall.
  Accumulations of 3 to 6 inches are possible north of Hwy 29 in
  north-central WI.

- Winds increase early Wednesday morning and afternoon with wind
  gusts to 45 mph or greater. The combination of windy
  conditions and ongoing light, fluffy snow will result in near-
  blizzard conditions at times Wednesday morning.

- Much colder temperatures move in beginning Wednesday and
  continue for an extended period with highs not getting above
  freezing for most locations into next week.

- Increasing confidence for additional accumulating snow late
  Friday and into Saturday. If you have after Thanksgiving
  travel plans for this weekend, be sure to monitor the forecast
  closely!

&&

.DISCUSSION...
Issued at 145 PM CST Tue Nov 25 2025

Rest of Today - Tonight: Rain Changing to Snow Overnight

Today will likely be our last "mild" day for quite some time as a
upper-level comma head shown on GOES-19 water vapor imagery and
25.15z RAP 500mb heights situated in the Dakotas pushes eastward
towards the local area. As this feature moves into the region, an
axis of rain will move through during the afternoon and early
evening as depicted in many of the CAMs out ahead of the surface
cold front associated with this system. As this robust cold
advection pushes into the area overnight, temperatures will
drop quickly falling through the 30s and into the 20s. While
much of the CAMs keep us in the dry slot during the overnight
hours initially with some subsidence behind the cold front,
eventually the backside deformation zone of this system will
sneak into the area with saturation increasing into the
dendritic zone and snow pushing into the local area as soon as
1-3am.

Wednesday: Windy with Snow and Much Colder

During the pre-dawn hours on Wednesday, the aforementioned
deformation zone will firmly push into the local area with
accumulating snow overspreading much of the area. In tandem with
this, winds will dramatically increase as a sharply increasing
low-level jet at 850mb positions over the area to 50-60 kts as
this system really intensifies right over the local area. The
eastward progressing wind gradient aloft in addition is really
quite remarkable as in a matter of two counties 850mb winds in
the RAP increase from 15 kts to near 60 kts. Consequently, winds
may noticeably increase rather rapidly overnight. As a result,
have made several changes to forecast and headlines over the
past few hours as recent Hi-Res guidance has ramped up the
surface winds fairly significantly. The 25.12z HREF has very
high probabilities (70-100% chance) for wind gusts over 45 mph
with even respectable probabilities (40-70% chance) for gusts
over 50 mph. This combined with falling and accumulating snow
will likely lead to near-blizzard conditions as joint
probabilities in the 25.12z HREF for 1/4 mile visibilities and
strong wind gusts are respectable on Wednesday morning (30-60%
chance). Needless to say, if you have any travel plans on
Wednesday for Thanksgiving consider delaying travel if at all
possible until afternoon when conditions will improve as the
deformation zone pushes east of the local area.

As far as accumulations are concerned, these will be limited to some
extent by the fact that the snow will occur in a fairly short time
frame on Wednesday morning. Regardless, the cold advection will push
the thermal profile into the dendritic growth zone aloft which will
coincide with fairly good vertical motion in the layer.
However, given the strong winds near the surface, this will
likely fracture any dendrites and thus lower snow ratios. So
thinking our snow to liquid ratios here will be around 13-15:1,
certainly a drier snow. Considering this, expecting
accumulations in between I-90 and Hwy 29 in the 1 to 4 inch
range as the 25.12z HREF has high probabilities (70-100%) for
amounts over 1 inch in this general area. Higher amounts north
of Hwy 29 in Taylor County seem more plausible as probabilistic
guidance in the HREF highlights this area for amounts in the
3-6" range as they will likely reside in the deformation zone
for a longer period. Consequently, have issued a Winter Weather
Advisory for areas near and north of I-90. What is important to
reiterate, is that while snow amounts may not be overly
significant, the strong winds in combination with falling snow
for the morning commute will make travel hazardous.

As this system exits the area, continued windy conditions and
northwesterly flow will usher in much colder air into the region.
Subsequently, temperatures will struggle to warm any on Wednesday
with highs not making it above the freezing mark in most areas, the
only exception being in river valley locations. So would expect some
slushy accumulations on roadways to occur as a result.

Thanksgiving - Sunday: Staying Cold, Weekend Snow Potential

As we head into the later part of the holiday week, the upper-level
trough that instigated this pattern change will slowly pull eastward
and subject the local area to a northwesterly flow. Consequently,
expecting temperatures to remain on the colder side with a
persistent continental polar airmass residing over the region.
As a result, much of ensemble guidance keeps highs in the 20s to
lower 30s for Thanksgiving and into Friday with this
reinforcing airmass in place. With little ridging working into
the area, would expect some cloud cover to linger which in
combination with steeper low-level lapse rates to around 7-8
C/km and weak 0-3km instability in the 25.12z NAM on
Thanksgiving could lead to some flurries and snow showers with
the cyclonic flow on the back edge of the upper-level trough,
primarily in north-central WI.

Eyes then turn to a potential secondary system to affect the local
area from late Friday and into Saturday night. The general
conceptual model depicted by deterministic guidance features a
relatively weak upper-level shortwave descending out of
Alberta/Manitoba, Canada and into the Northern Plains. As this
occurs, deterministic guidance has this wave phasing with a southern
stream wave in the Central Plains which in turn aids in the
development of a strong surface low. The main point of disagreement
with this system is exactly when/where this phasing of these waves
occurs and how the surface low responds.

Cluster analysis of the grand ensemble (GEFS/EC/Canadian ensemble)
gives some hints to the scenarios at play with the more amplified
and earlier phasing trough system allowing more room for the
attending surface low to push north. In this scenario, the
probability for 3 inches or greater (assuming a 10:1 ratio, this
will likely be higher) are respectable (30-60% chance) south of the
MN/IA state line in the grand ensemble as the low treks slightly
further north. The other scenario would keep the surface low weaker,
have the phasing occur later and keep the surface low further south
which would not favor more robust snow accumulations as much (10-40%
chance for 3 inches south of MN/IA state line). Whats also is important
to note in the NBM and deterministic runs are more aggressive
with the recent NBM having high probabilities (50-80% chance) for
6 inches or greater of snow accumulation south of I-94 over the
course of the weekend. Regardless, confidence is quite high
(80-100% chance) in the grand ensemble (GEFS/EC/Canadian
ensemble) for at least measurable snowfall for much of the
region in the grand ensemble so certainly will be the next
system to keep our eyes on and if you have post-Thanksgiving
travel plans be sure to watch the forecast for the weekend
closely!

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1141 AM CST Tue Nov 25 2025

Lowered flight categories due to both visibility and CIGS,
mainly IFR to LIFR, through the overnight period then increasing
to MVFR to IFR for Wednesday morning. Light rain will move
through the area this afternoon and into the early evening.
There will be a slight break in the rain this evening and early
overnight, however with the low level saturation and lowered
CIGS (between 500 and 1500ft), mist will likely continue. During
the overnight, a rain/snow line moves into southeast Minnesota
and northeast Iowa between 03 and 05Z. This line will move east
and is expected to be at the KLSE terminal between 06 and 08Z.
Behind this rain/snow line, light snow will continue to fall
through the morning. Light south winds this afternoon will
gradually pick up this evening then switch to northwest winds as
a cold front moves through. With sustained winds of 25 and 35
mph and gusts between 45 and 55 mph, blowing snow will be likely
across open areas. The wind gusts diminish a little bit into the
afternoon.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory from midnight tonight to 9 AM CST
     Wednesday for WIZ032-033.
     Winter Weather Advisory from 3 AM to noon CST Wednesday for
     WIZ017-029-034-041>044-053.
     Wind Advisory from 3 AM to 3 PM CST Wednesday for WIZ032>034-
     041>044-053>055-061.
MN...Wind Advisory from midnight tonight to noon CST Wednesday for
     MNZ079-086>088-094>096.
     Winter Weather Advisory from midnight tonight to 9 AM CST
     Wednesday for MNZ079-086>088-094-095.
     Winter Weather Advisory from 3 AM to noon CST Wednesday for
     MNZ096.
IA...Wind Advisory from midnight tonight to noon CST Wednesday for
     IAZ008>011-018-019-029-030.

&&

$$

DISCUSSION...Naylor
AVIATION...Cecava