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000
FXUS63 KARX 200849
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
349 AM CDT Sat Apr 20 2024

.KEY MESSAGES...

- Freeze warning continues for eastern MN, northeast IA, and
  parts of western WI through early morning.

- Continued below normal temperatures today with some
  flurries/flurry-rain mix today and freeze headlines expected
  again for Sunday morning.

- Shower chances Monday night and Tuesday (80% chance less than
  0.25"); how cold Wednesday morning? Current probabilities for
  lows <32 degrees F are 70% near Medford to 30-40% toward New
  Hampton and Elkader IA.

- More Seasonable to end the week, but shower and thunderstorm
  chances return.

&&

.DISCUSSION...
Issued at 330 AM CDT Sat Apr 20 2024

Overview:

It felt more like March than April Friday as several locations were
held to the 40s. Combined with gusty northwest winds mostly 38 to 48
mph; it felt quite blustery.  Rochester topped out at 56 mph!

Water vapor satellite imagery and heights early this morning showed
a seasonably strong, broad trough encompassing much for the U.S. and
was centered over Hudson Bay. A 500mb ridge was located over the
West Coast. The surface map showed west to northwest winds with
a re-inforcing cold front upstream. By 3am, temperatures were
in the 30s area-wide with a few upper 20s. Winds were northwest mostly
5 to 15 mph with gusts 15 to 25 mph. Nighttime microphysics
satellite imagery and radar showed considerable clouds across
the region with flurries/flurry-rain mix and trace reports of
precipitation. Some of the snow showers were working into
Wabasha County and Medford had dropped to less than 3 miles for
a time.

Continued below normal temperatures today with some flurries/flurry-
rain mix today and freeze headlines expected for Sunday morning:

We remain under the influence of cyclonic flow today as re-inforcing
cold air arrives this morning.  Light snow/flurries have been noted
on the upstream obs and a few snow showers have been steadily
dropping southeast toward the forecast area with some visibility
restrictions 2 to 5 miles. Forecast soundings show convective
temperatures in the mid 30s with increasing moisture 1500-3800ft AGL
during the day with low freezing levels.  Thus, expect areas of
clouds to re-develop today. There is better warm air aloft early
this morning and again some weaker warm air aloft this afternoon
with some upper level jet support this afternoon. The HRRR had
some hints at snow showers from 18Z on, but the most recent
20.07Z run had backed off on this somewhat. The RAP more from
21Z on. The Hi-res models have not picked up on the current
activity well, thus this lowers confidence. Did add low pops to
the forecast today for flurries or a flurry/rain mix. Continued
brisk northwest winds today, but not as strong as Friday with
gusts mostly 15 to 25 mph. Temperatures remain below normal with
highs in the 40s.

The skies clear tonight with diminishing winds.  With the chilly
airmass in place, low temperatures look to fall into the mid-20s to
lower 30s.  With these freezing temperatures again forecast, we`ll
likely need another freeze warning headline for Sunday morning.

Mid-level ridging builds in for Sunday.  Northwest winds continue
with a relatively dry airmass.  Weekend precipitable water values
are 50 to 75% of normal, but with the warmer temperatures Sunday,
lowest relatively humidities lower to 20 to 30%.  Northwest winds
again gusting 15 to 30 mph. East of the Mississippi river
Monday, it will be dry with strengthening winds area-wide with
gusts 25 to 40 mph. Dewpoints gradually increase west of the
Mississippi River. Highs Monday top out in the 60s with rain
chances increasing during the afternoon.

Attention turns to fire weather concerns. With the recent
snow/rains, there has been some progress on green-up and the
Fine Fuel Moisture is mostly in the 80s Sunday and Monday. With
low RH values and stronger winds gusts, we`ll continue to
coordinate with local officials each day related to fire weather
concerns.

Shower chances Monday night and Tuesday; how cold Wednesday
morning?

Monday afternoon/Monday night, an area of low pressure will track
through the U.P. of Michigan with a surface cold front passing
through the local area.  This will bring a good chance for light
rain especially Monday night and again Tuesday afternoon with a
re-inforcing cold front. There is a 30-50% chance of 0.1" or
more with an 80% chance of the rain being less than 0.25".
Behind the cold front Tuesday afternoon, temperatures could
again be below freezing Wednesday morning. This far out, there
is not good agreement with a large spread in solutions. The
current GEFS/EC/Canadian ensembles means are 29-35 for the local
area for Wednesday morning.

More Seasonable to end the week, but shower and thunderstorm
chances return:

Temperatures are currently forecast to moderate into the 60s
for the end of the week with the potential for another storm
system to bring showers/thunderstorms to the region Thursday
night/Friday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1102 PM CDT Fri Apr 19 2024

A series of northern stream systems will keep skies mostly
cloudy through the TAF period. Ceilings will be VFR. With
a tight surface pressure gradient continuing, sustained west
and northwest winds will be in the 10 to 20 knot range with
wind gusts of 20 to 30 knots.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Freeze Warning until 8 AM CDT this morning for WIZ032-033-041-
     053>055-061.
MN...Freeze Warning until 8 AM CDT this morning for MNZ079-086>088-
     094>096.
IA...Freeze Warning until 8 AM CDT this morning for IAZ008>011-018-
     019-029-030.

&&

$$

DISCUSSION...Zapotocny
AVIATION...Boyne