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