575
FXUS63 KARX 311045
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
545 AM CDT Mon Aug 31 2026

.KEY MESSAGES...

- Low confidence (<25%) in storms today increases Tuesday and
  Wednesday night.

- Above normal temperatures from the mid 80s to 90s expected
  through midweek.

&&

.DISCUSSION...
Issued at 146 AM CDT Mon Aug 31 2026

Warming Through The Week With Frequent Precipitation Chances:

A cyclonically wrapping extratropical cyclone on upper level
water vapor imagery loops slowly trudges east through the start
of the new week, circumnavigating and exerting influence on a
synoptic upper level ridge over the central CONUS, resulting in
the local forecast area sandwiched in the accompanying
confluence zone. Resultant periodic precipitation and storm
chances frequent the local forecast area mostly during the
nighttime hours through the start of the week.

Storm Chances Today:

Daily lowest local confidence (<25%) for storms Today can be
attributed to high resolution soundings suggesting low level
dry air causing a capping inversion. Learning from Sunday, when
storms were able to initiate under similar model conditions as
widespread sky cover throughout the daytime hours limited low
level mixing, resulting in more moist lower levels than
previously expected, and high based (8000`) storms accessing mid
level instability. Therefore, have veered away from high
resolution models for Today which again suggest copious mixing
causing a strong, dry low level inversion. Degree of
cooling/moistening of low level inversion will be determining
factor in coverage and strength of storms through today. More
boisterous solutions in previous RAP (30.21Z) and recent HRRR
(31.00Z) raises local concerns for potentially severe storms in
a very narrow temporal and spatial window within convergent zone
along surface frontal boundary. Large hail and damaging winds
would be the main threats should severe storms come to fruition.

Storm Chances Through The Week:

Confidence in storms increases through the start of the week,
from Tuesday night as moisture-laden southwest low level flow
advects northeast along a meager, lifting upper/mid level
perturbation behind the exiting synoptic trough axis and again
Wednesday night as a narrow corridor of higher
storm/precipitation potential from a burbling low level theta e
lobe along our southern periphery again advecting northeast.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 539 AM CDT Mon Aug 31 2026

Concerned that a MCV might be generated from the convective
complex currently located over Kansas and Nebraska. If one does
develop, it might bring a round of showers and storms mainly
south of Interstate 90 this afternoon. A few of these storms
might become strong. This precipitation would be likely south
of the TAF sites.

Some CAMs suggest that there might be some fog at KLSE overnight
tonight. At this time, there is plenty of uncertainty, so kept
it out of the TAF at this time.

&&

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

&&

$$

DISCUSSION...JAR
AVIATION...Boyne