712
FXUS63 KARX 241923
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
223 PM CDT Tue Jun 24 2025

.KEY MESSAGES...

- Localized heavy rain will be possible along and south of the
  Interstate 90 corridor this afternoon and evening.

- Funnel clouds possible through 7 PM in northeast Iowa.

- Several rounds of heavy rain expected from late tonight into
  Thursday night. If training storms can occur, there will be
  the potential of flash flooding.

&&

.DISCUSSION...
Issued at 223 PM CDT Tue Jun 24 2025

This Afternoon into the Evening

Showers and isolated thunderstorms will continue to be found
along a tight CAPE gradient and 850-700 mb frontogenesis along
or just south of the Interstate 90 corridor for this afternoon.
With warm cloud layer depths in the 3.5 to 4 km range and
precipitable water values near 1.7 inches, these showers and
storms have been highly efficient rain producers. Our office
received 1.8 inches of rain between 7 AM this morning to 1 PM
this afternoon. The SPC mesoscale analysis page hints that as a
cold pool develops this afternoon and that it will nudge these
showers and storms about a county further south late this
afternoon and evening.

Differential heating across northeast Iowa has increased the 0-3
km CAPES up to 150 J/kg in the latest SPC mesoscale analysis.
In addition, it shows shows some low level vorticity in this
area. This has resulted in a few reports of funnel clouds in
northeast Iowa. These conditions will likely remain supportive
for additional reports through 7 PM this evening.

Late Tonight into Thursday Night

For late tonight, a shortwave trough will approach the region
from the Central Plains. This will allow the surface front near
the Interstate 80 corridor to start to move back north late
tonight and Wednesday. This front is then expected to stall
somewhere in northeast Iowa and southwest Wisconsin on Wednesday
night and remain quasi-stationary into Thursday night.

As several waves move along this quasi-stationary boundary
there will be several rounds of showers and storms moving east
through the region. It continues to look like the precipitable
water values along and north of this front will be near 2 inches
and between 1.8 and 2 inches south of this front. Like today, warm
cloud layer depths range from 3.5 to 4 km range. This will result
in highly efficient rain producers.

The mean QPF from 12z Wednesday through 12z Thursday remains in
the 1 to 2 inch range for northeast Iowa, southeast
Minnesota,and west-central Wisconsin. The localized probability-
matched mean has some totals approaching 5 inches in the
forecast area.


The mean QPF from 12z Thursday through 12z Friday ranges from 1
to 4 inches. The heaviest rain at this time looks to be from
the Twin Cities northeast to western Upper Michigan and over
western Iowa. The localized probability-matched mean has some
totals in the 5 to 7 inch range in the forecast area.

Like yesterday, the flooding potential remains unclear due to
uncertainties on where this front will be located and where
training showers and storms are able to occur.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1221 PM CDT Tue Jun 24 2025

VFR to low end MVFR ceilings currently present across the area
with scattered showers and a few thunderstorms, mainly along and
south of the I-90 corridor. This scattered activity will
continue through the afternoon with 850-700mb frontogenesis over
this area allowing for continued lift/development. Rain chances
decrease into the evening before another surge of widespread
rain/thunderstorms moves in late overnight and continues through
tomorrow afternoon. Not sure how widespread the thunder will be
for now so have gone with some PROB30s to cover this possibility.
CIGs will deteriorate overnight with widespread IFR to LIFR
early tomorrow morning before starting to scatter out to
MVFR/low end VFR by 18Z tomorrow afternoon. Winds through the
period will be light at less than 10 kts, mainly out of the
west to southwest.

&&

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

&&

$$

DISCUSSION...Boyne
AVIATION...Barendse