Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 302331
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
531 PM CST Mon Jan 30 2023

.DISCUSSION...(This evening through Monday)
Issued at 255 PM CST Mon Jan 30 2023

Key Messages:

 - Bitter cold temperatures to end the month.

 - Another blast of cold Thursday night and Friday.

 - Warmer for the weekend with small chances for snow.

Overview:

Overnight lows ranged from a few degrees above zero over southwest
Wisconsin to -10 to -13 for parts of west central Wisconsin,
southeast Minnesota, and northeast Iowa.  The coldest wind chills
were -24 to -28 near Rochester/Eyota, and in Taylor, Dodge, Wabasha,
Winona, and Mower counties.

Water vapor satellite imagery/heights show a mid-tropospheric trough
over Hudson Bay extending southwestward through the Northern Plains
and Rockies toward closed low pressure off the southern California
coast. At 20Z...a 1035mb area of surface high pressure was centered
over southeast South Dakota.   This broad area of surface high
pressure extended well into MN/IA.  20Z temperatures were mostly in
the single digits with light northwest winds 5 to 15 mph with a
few patchy clouds. Surface dewpoints were in the single digits
below zero, however to the west, they were more -10 to -20.

Through mid-day Tuesday, the cold air will remain in place, with the
cold air beginning to retreat as the ridge over the West Coast
begins to affect the area with rising heights.

Bitter cold wind chills tonight and Tuesday morning:

There remains some large differences in the MOS guidance tonight
with temperature and dewpoint forecasts.  The MAV guidance at
Medford has -22 and the MET, -15.  Similarly, the RAP has dewpoint
temperatures plummet to -30 to -38 for dewpoints toward RST.  Our in-
house verification shows that the NBM/CONSALL do a good job.  This
would put dewpoints in the -10 to -20 degree range. Surface high
pressure passes to our south with light and variable winds becoming
southwest or (southeast at LSE). The 900mb winds are a minimum
through 06Z...then begin to increase from the west to around 20 or
25kts. With fresh snowpack for some and the forecast soundings
showing a strong inversion with good radiational cooling...have lows
of -10 to -20. The winds will be light northwest then southwest,
increasing after 12Z Tuesday. Coldest wind chills drop to -20 to
minus 35, thus have issued a wind chill advisory for the forecast
area through 16Z Tuesday. Temperatures remain in the single
digits and teens for Tuesday with single digit above and below
zero Wednesday morning.

Wednesday Not As Cold, but another Arctic Blast Thursday night and
Friday:

Wednesday, return flow sets up with rising heights and warmer
temperatures with highs in the teens and 20s.  Temperatures Thursday
will be similar, however...another shot of cold air arrives with the
current timing of falling temperatures in the afternoon. Patchy
clouds are on tap and there could be some flurries with the surge
of cold air Thursday.

The NAEFS anomalies for Friday are 1 to 2 standard deviations below
normal. The NAEFS ENS are similar...but still more around 2.  A 1040
large area of high pressure plunges southward with 850mb
temperatures by Friday morning around -18 deg C.  Lows of -5 to -15
are forecast with bitter cold wind chills again of -15 to -30.

A clipper brings a chance for light snow Saturday, but also warmer
temperatures in the 20s and 30s for the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 529 PM CST Mon Jan 30 2023

VFR conditions persist through the TAF period. Patchy high level
clouds move over the terminals periodically, but in general mostly
clear skies with bitterly cold wind chills early tomorrow morning.
Winds shift to the southwest later this evening but remain light
overnight. Winds strengthen to 10-15 knots tomorrow afternoon
with gusts up to 20 knots Tuesday afternoon.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Wind Chill Advisory until 10 AM CST Tuesday for WIZ017-029-
     032>034-041>044-053>055-061.

MN...Wind Chill Advisory until 10 AM CST Tuesday for MNZ079-086>088-
     094>096.

IA...Wind Chill Advisory until 10 AM CST Tuesday for IAZ008>011-018-
     019-029-030.

&&

$$

DISCUSSION...Zapotocny
AVIATION...KAA


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