632
FXUS63 KARX 100035
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
635 PM CST Tue Dec 9 2025

.KEY MESSAGES...

- Heavy snow north of I-94 where 4 to 6 inches is expected
  within 4-6 hours under snowfall rates of 1-1.5 inches/hour.
  Periods of moderate to heavy snow to the south through this
  evening with a brief lull south of I-90 between 9pm and
  midnight, followed by more snow shortly thereafter.

- Strong winds gusting to 35 to 45 mph after midnight, coupled
  with the second round of snow, will lead to some blowing and
  drifting of snow in open areas.

- Temperatures begin to fall Wednesday through the rest of the
  week, with highs on Friday and Saturday struggling to climb
  out of the single digits. Wind chills of -25F or lower are
  possible (30-70%).

&&

.UPDATE...
Issued at 631 PM CST Tue Dec 9 2025

The threat for freezing rain is rapidly coming to an end as
warmer air lifts northward ahead of the approaching low
centroid, ceasing by 8pm in southeast MN and northeast IA.
Therefore have started to shift the messaging away from the
freezing rain to the snow.

&&

.DISCUSSION...
Issued at 212 PM CST Tue Dec 9 2025

This Afternoon and Evening

Messy winter weather this afternoon into this evening remains
the primary focus of the forecast as a quick hitting dynamic
system currently situated over the Dakotas moves southeastward
into the region. Starting from the north, snow is expected to
fall, primarily along and north of I-94, highest over Taylor and
Clark counties where a band of 5-7 inches of snow is expected
associated with 900-700hPa frontogenesis. Snowfall rates of
1-1.5 inches are possible per the 09.12z HREF which will lead to
these accumulations over a short period, on the order of around
6 hours. A slight southward shift in the recent High-Resolution
guidance brings some higher amounts towards the I-94 corridor
which primarily affects the northern portions of Jackson,
Juneau, and Adams counties.

Working south, light freezing rain has been observed in west-central
Minnesota this afternoon which is expected to spread southeast into
the region over the next few hours. 850hPa warm air advection
continues, nudging temperatures above freezing over areas south
and west of I-94 which is expected to be enough to warrant some
freezing rain across portions of southeast Minnesota, northeast
Iowa, and southwest Wisconsin this afternoon and evening. There
is a question of how much dry air will be in place within this
warm nose, but a saturated atmosphere above combined with strong
forcing from the dynamic system should be able to overcome
this. Overall, expecting generally a glaze to a 0.05" of ice
accumulation over the aforementioned areas. As warm air
advection continues under southerly flow, a transition to all
rain is expected before colder air is ushered into the region,
allowing for a transition to snow overnight.

Strong Winds and Additional Snowfall Overnight

The synoptic low level wind field increases drastically overnight
for areas west of the Mississippi River into far southwestern
Wisconsin as the pressure gradient associated with this winter
system tightens in response to the low deepening over
Minnesota/Wisconsin. As a result, surface winds increase overnight
into Wednesday morning, with gusts of 40+ mph possible. 09.12z HREF
probabilities are the highest with regard to wind gusts, suggesting
70-90% for gusts greater than 45 mph, only 10-20% in the 09.13z NBM.
Confidence leans towards the stronger wind gust solution given
steepening 0-2km lapse rates, nearly unidirectional wind profile,
and observed winds over the northern Great Plains of 35-45mph.
Despite this confidence, have opted to not issue a Wind Advisory
this afternoon to avoid confusion with the ongoing Winter Weather
Advisory across these areas.

Along with the strong winds, additional accumulating snowfall is
expected overnight along the cold front, generally up to 1 inch
and primarily along and north of I-90. The potential for
intense bursts of snow has fallen off dramatically as low level
lapse rates in the RAP/HRRR/NAM soundings have decreased in
recent runs, limiting the convective nature of the snowfall.
Still expecting difficult travel during this period given the
strong winds and snowfall, but the intense bursts seem less
likely than 24 hours ago.

Very Cold Temperatures Late This Week

Cold air moves into the region behind tonight`s system under
northwest flow, resulting in falling temperatures through the
weekend. Temperatures are currently expected to bottom out Saturday
and Saturday night when the 09.13z NBM mean suggests highs in the
single digits above and below zero and overnight lows in the single
to double digits below zero. Given there are still several days
between now and the weekend, exact values are not certain. However,
probabilities continue to suggest that very cold wind chills are
possible Friday night and again Saturday night with the 09.00z
LREF suggesting 30-60% and 50-70% probabilities for wind chills
less than -25C, respectively.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 555 PM CST Tue Dec 9 2025

Widespread MVFR to IFR snow, mixing in with freezing rain
before 02Z southwest of a RST to DBQ line, impacts much of the
area overnight. There may be a period of lower impacts south of
an RST to DLL line between 02Z and 06Z before snow spreads back
southward. As the snow spreads back south after 06Z, our current
10-15kt southerly winds rapidly veer to the W/NW and increase
to 15-25G25-40kts, strongest west of the Mississippi River,
which could lead to blowing snow and LIFR impacts. Conditions
improve and winds slowly decrease after 12Z, but MVFR ceilings
and blustery northwest winds linger through the day along with
low chances (20-40%) for impactful snow showers.

Additional weather systems that could being aviation impacts
loom for Thursday and Friday.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until 6 AM CST Wednesday for
     WIZ032>034-041>044-053>055-061.
     Winter Storm Warning until 6 AM CST Wednesday for WIZ017-029.
MN...Winter Weather Advisory until 6 AM CST Wednesday for MNZ079-
     086>088-094>096.
IA...Winter Weather Advisory until 6 AM CST Wednesday for
     IAZ008>011-018-019-029-030.

&&

$$

UPDATE...Skow
DISCUSSION...Falkinham
AVIATION...Skow