938
FXUS63 KARX 042345
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
545 PM CST Wed Dec 4 2024

.KEY MESSAGES...

- Strong northwest winds gusting 45 to 55 mph will persist
  through the evening and a Wind Advisory remains in effect.

- Cold start to Thu with -5 to -15 F wind chills.

- Above normal temps return for the weekend with highs into the
  40s for many, Sunday looking like the warmest day.

&&

.DISCUSSION...
Issued at 210 PM CST Wed Dec 4 2024

- TONIGHT/THU MORNING: strong winds persisting through the evening,
cold start to the day Thursday.

The strong/gusty winds will persist through the evening hours, but as
the storm system shifts east overnight...the pressure gradient will
star to slacken, mixing in the near sfc layer won`t be as deep nor
as uni-directional farther a loft, and the strongest low level cold
air advection shifts south/east. So, a drop in wind speed is
expected - still blustery - but enough that the wind advisory should
not need to be extended past midnight.

RAP/HRRR bufkit soundings continue to point to weak instability,
with RAP 1000:850 C/km also still pegging 8-9 C/km through the rest
of the afternoon hours. Radar imagery shows numerous snow showers
over central MN, mostly parallel to the mean flow, with a mix bag in
visibilities. This will spread across the local area through the
afternoon hours, gradually diminishing in extent/intensity and
exiting southeast by early evening. Accumulations still look to be
minor.

Strong influx of cold air, comparatively to the season, flows in
tonight with lows still looking to bottom out in the single digits
for most. Add in the still blustery winds and wind chills from -5 to
-15 will greet those headed to work/school Thu morning. Bundle up!


- WEEKEND: much warmer! Highs into the 40s for most Sunday.

Shortwave ridging builds across the upper mississippi river valley
for the weekend, providing an avenue for more seasonable to mild air
to surge northward. The EPS and GEFS have been very consistent in
this warming with approx 75% of both their ensemble suites pushing
40+ highs for most of the local area Sunday. The upper 5-10% suggest
50 could be reached at a location or two. A few degrees cooler
Sat/Mon.

Pcpn chances could return for Sunday night/Mon as the ridge starts
to exit east and a shortwave trough scoots across the region. EPS
and GEFS members currently hold the bulk of related QPF to the north
and south, although low level thermodynamics will aid pcpn chances
locally.


- NEXT WEEK: trending seasonable with periodic pcpn chance

After a quick shot of colder (but not as cold as Thu) air with the
shortwave for Monday, the long range models currently favoring more
zonal to broad ridging to work back in for much of the new week.
Moderating temps more in line with the seasonable norms would
result. Not much for pcpn chances at this time.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 541 PM CST Wed Dec 4 2024

Widespread snow showers, bringing periods of IFR to even LIFR
visibilities, shift east of the region by 02-03Z, with MVFR to
VFR ceilings lingering for the rest of the night. Confidence is
low in when these ceilings will clear, but the current
indications are possibly around mid to late morning. Strong and
gusty northwesterly winds of 20-30G30-40kts slowly subside
through the night and the morning hours, becoming 5-10kts from
the WNW at by Thursday afternoon.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Wind Advisory until midnight CST tonight for WIZ017-029-
     032>034-041>044-053>055-061.
MN...Wind Advisory until midnight CST tonight for MNZ079-086>088-
     094>096.
IA...Wind Advisory until midnight CST tonight for IAZ008>011-018-
     019-029-030.

&&

$$

DISCUSSION...Rieck
AVIATION...Skow