471
FXUS63 KARX 021919
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
219 PM CDT Thu May 2 2024

.KEY MESSAGES...

- Another round of showers late Friday night into Saturday.
  Rainfall amounts of up to a half of an inch possible.

- Active weather pattern develops for next week. Periodic
  showers and storm chances through the period. Severe potential
  will depend on timing of each individual systems.

&&

.DISCUSSION...
Issued at 219 PM CDT Thu May 2 2024

Today through Friday:

Rain will continue to move through the area and into central
Wisconsin. Compared to previous forecasts, model guidance
continues to push the greater instability to our southeast, into
eastern Iowa, northern Illinois, and far southern Wisconsin. As
a result, this will be the area where thunderstorms develop.
Scattered showers will be possible this afternoon, with
northeastern Iowa and southwestern Wisconsin being the areas
that have the greatest potential to see these showers. With
these showers, there is a small chance (10 to 20%) of thunder.
All rain chances are expected to diminish by midnight in our
area. Low clouds will continue to be in the area through the
overnight hours. Skies will gradually clear up and by Friday
mid-morning, clear skies are expected across the area. Southerly
flow will return for Friday out ahead of the next shortwave
trough that will bring us more rain late Friday night into
Saturday.

Friday night through Saturday

Next concern is shower/storm chances late Friday night/Saturday
across the forecast area. Another impulse embedded in the
southwesterly flow aloft will track into the Upper Great Lakes
Region late Friday night/Saturday. The 02.12z GFS/NAM show decent QG
forcing/vertical motion in association with the impulse. This will
spread precipitation over the forecast area late Friday night into
Saturday. Thunderstorm chances continue to diminish...as latest
bufkit soundings and GFS/NAM indicate very little or if any 0-6km
Most Unstable CAPE...less than 100 j/kg. With the limited
instability have removed mention of thunder for Saturday and the
forecast area should see all showers/rain.

Shortwave ridge builds into the Northern Plains/Upper Great Lakes
region Sunday. Subsidence underneath ridge should allow for dry
weather and temperatures will be near normal with highs in the
middle 60s to around 70.

Sunday night through Thursday

Main forecast concerns from Sunday night through Thursday are
shower/storm chances mainly from Monday evening through Thursday.
Shortwave ridge over the region Sunday night into Monday breaks down
Monday evening. Upper level closed low slowly moves over the
Northern Plains States and pieces of energy rotating around the
closed upper level low are expected to track over the forecast area
Monday night into Thursday. Latest ensembles/deterministic models
suggest there are differences in timing of the pieces of energy
moving over the Upper Mississippi River Valley...especially the
first piece of energy Monday afternoon. This will have impacts on
any potential severe storms or when the convection moves into the
forecast area. Temperatures will remain near or slightly above
normal through the forecast period...with highs in the middle to
upper 60 to middle 70s.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1227 PM CDT Thu May 2 2024

Southeasterly winds will switch to northwesterly winds during
the afternoon. These winds will stay out of the northwest until
the overnight period, when southwesterly winds will take over
and last through Friday morning. A band of rain will continue to
move into central Wisconsin this afternoon. Scattered showers
and thunderstorms will continue to be possible through the
afternoon, however the favored areas for these to develop are in
eastern Iowa and southern Wisconsin. CIGS are expected to stay
MVFR to IFR for most locations through the day today. Skies
will gradually clear up after midnight and by Friday mid-
morning, skies will be clear across the area.

&&

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

&&

$$

DISCUSSION...DTJ
AVIATION...Cecava