825
FXUS63 KARX 102324
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
624 PM CDT Mon Aug 10 2026

.KEY MESSAGES...

- Showers and storms are possible (15 to 20%) for far southwest
  Wisconsin this evening. More widespread storm chances (30 to
  70%) for tonight through Tuesday morning as a complex of
  storms moves through portions of the forecast area. The main
  hazard with these storms would be damaging winds.

- Periodic storm chances are possible throughout the rest of
  the forecast period.

- Temperatures remain near normal through midweek with a cooling
  trend for the latter half of the week

&&

.DISCUSSION...
Issued at 145 PM CDT Mon Aug 10 2026

Today - Tuesday: Storm Potential

After a foggy start to the day, mostly dry conditions are expected
until early Tuesday morning. There is a low chance (<10%) for a
shower or storm early this afternoon across the CWA. The better
storm chances are in eastern Iowa and northern Illinois for this
afternoon and evening as a weak boundary shifts northeastward. Some
of the CAMs are hinting at the possibility of far southwestern
Wisconsin getting in on some of the shower/storm potential (15 to
20%). Heading into the overnight and early morning timeframe, a well-
defined wave forms in eastern South Dakota and western Minnesota.
Aided by 2000 to 3000 J/kg of MLCAPE and DCAPE values of 800 to 1200
J/kg and good amounts of 0-6km shear (40 to 50 kts), a MCS is
expected to form in western Minnesota later tonight. This MCS will
have the aforementioned parameters to work with, allowing it to
maintain itself through the morning. The boundary that this MCS will
stay on is oriented more west-northwest to east-southeast. This
means if it held together, it would impact northeast Iowa and far
southwest Wisconsin in the early to mid-morning hours Tuesday. CAMs
are not in good agreement on the exact timing of this system as the
range for when it could enter our western counties is between 4AM
and 8AM. There also remains a little uncertainty on the exact path
this MCS takes, as some models have it further north, impacting the
I-90 corridor. These details will be refined later today as we get
closer, however the main hazard with this system will be damaging
wind gusts.

Tuesday Night - Wednesday: Another Potential MCS

Much of the forecast area should be suppressed from any additional
storm development during the afternoon and evening on Tuesday due to
the morning MCS, however areas north of I-94 could see some storm
development by the evening, as this area is expected to be not be
impacted from the morning storms. Heading into the overnight period,
a similar story develops as a wave, that looks more well-defined
than tonight`s wave, comes down through the Upper Midwest. Where the
boundary from tonight/Tuesday morning will play an important role
for where Tuesday nights/Wednesday mornings MCS goes. Now there is
uncertainty on if this MCS will survive southeast of a northeast
Nebraska into central Minnesota line, however some models do have a
MCS or line of storms moving through northern Iowa and southern
Minnesota Wednesday morning. The GFS is the most northern solution,
however this could be due to its poleward bias. The HRRR has it
mostly in central and eastern Iowa with a couple northeast Iowa
counties potentially involved. Confidence will increase heading into
Tuesday evening once we know where the boundary sets up and how
convection is ongoing upstream.

Thursday - Early Next Week: More Storm Chances, Slightly Cooler

Ensemble and deterministic guidance both favor a transition from
zonal/northwest flow to southwest flow aloft by the end of the week
and a ridge building in for the southeast US this weekend  Due to
our proximity to the jet stream and not directly under the ridge,
the warmer temperatures stay to our south and southeast. Cooler air
actually moves south into the region keeping temperatures largely in
the 70s. With a continued southwesterly fetch of moisture, daily
storm chances are possible into early next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 624 PM CDT Mon Aug 10 2026

VFR conditions give way to the potential for MVFR to IFR reductions
early Tuesday morning. Showers and storms will be the primary
aviation concern during the 10z to 17z period with IFR reductions in
the heaviest storms. These storms may be strong to severe as well
with the potential for damaging wind gusts. Otherwise, storms will
exit east by noon leaving VFR conditions in their wake with easterly
winds around 5 kts trending to light and variable by Tuesday
evening.

&&

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

&&

$$

DISCUSSION...Cecava
AVIATION...Naylor