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000
FXUS63 KARX 231120
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
620 AM CDT Tue Apr 23 2024

.KEY MESSAGES...

- Scattered showers and a few storms mainly this afternoon.
  Storms should remain below severe limits...gusty winds are
  expected with the showers/storms.

- Cooler tonight into Wednesday. Low temperatures tonight will
  fall into the middle 20s to middle 30s.

- Several rounds of showers and storms Thursday night into
  Monday. Heavy rain and severe potential will depend on track
  of surface features during this time.

&&

.DISCUSSION...
Issued at 313 AM CDT Tue Apr 23 2024

Today through Thursday

Latest water vapor satellite imagery shows vigorous shortwave trough
over the Northern Plains States/International border. Latest mosaic
radar indicates scattered showers across North Dakota/northern
Minnesota in association with the shortwave trough. Shortwave trough
will track southeast over the Upper Mississippi River today. The
23.00z GFS/NAM show decent 500-300mb positive vorticity advection
with the shortwave trough. Along with daytime heating/lift scattered
showers will continue under the shortwave trough and move over
mainly the northern half of the forecast area. Bufkit soundings
indicate limited instability of  up to 300 j/kg surface base CAPE
across the forecast area this afternoon. A few storms are expected
in amongst the scattered showers. Storms should remain below severe
limits. However...with dry airmass/deep mixing and bufkit soundings
showing inverted V sounding...some of the storms/showers could
produce gusty winds and small hail this afternoon.

Colder airmass advects into the forecast area behind shortwave
trough tonight into Wednesday. Clear skies/light winds and 925mb
temperatures cooling to minus 4 to plus 1 degree celsius by 12z
Wednesday will allow temperatures to drop into the middle 20s to
middle 30s tonight. Both Wednesday into Thursday will remain mainly
dry over the forecast area...as upper level ridge builds over the
Upper Mississippi River Valley.

Friday through Monday

Main forecast concerns Friday through Monday are showers/storms
through the forecast period. Upper level ridge builds over the
eastern United States this weekend and southwesterly flow aloft
develops over central United States. Several pieces of energy
embedded in the southwesterly flow will move over the Upper Great
Lakes/Upper Mississippi River valley and provide periods of
showers/storms through the forecast period. Latest
deterministic/ensembles show ample moisture transport/convergence
during this period and could lead to the possibility of heavy rain
across parts of the forecast area. Given differences in surface low
track/features...confidence is low where the heavy rain/severe
potential will occur at this time.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 620 AM CDT Tue Apr 23 2024

Scattered showers and thunderstorms are expected during the
afternoon and evening today. Gusty winds are the main threat
with these storms. Drier conditions for Wednesday. Some high
level clouds this morning then as precipitation enters the
region, CIGS drop to near 5kft. These lowered CIGS are not
expected to last long, as skies will clear after midnight.
Southwest winds will transition to northwest winds this morning.
Gusts this afternoon will be between 20 and 30 mph.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.

&&

$$

DISCUSSION...DTJ
AVIATION...Cecava