221
FXUS63 KARX 101051
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
551 AM CDT Mon Aug 10 2026

.KEY MESSAGES...

- Likely dry (80%) today, persistent precipitation potential
  from Tuesday through Thursday across the local forecast area,
  shunted along southern periphery until Saturday.

- Cooler and drier for the latter half of the week for much of
  the local forecast area.

&&

.DISCUSSION...
Issued at 1256 AM CDT Mon Aug 10 2026

Low Confidence, Persistent Precipitation Potential After Tuesday:

A relatively nebulous synoptic pattern leaves much to be desired
regarding precipitation and storm confidence through the week.
Regardless, a well saturated airmass south of a quasi-stationary
boundary near or over the southern half of the local forecast area
from northeast Iowa into southwest Wisconsin eventually expected to
be shunted along our southern periphery through the latter half of
the week. However, initial near term model consensus increases
precipitation potential due to increasing low level moisture Tuesday
morning and again Tuesday night.

While overall confidence is low, the warm, moist airmass has the
potential for enhanced instability (2000+ J/kg, LREF) due to the
warm frontal boundary potentially providing sufficient lift towards
higher deep layer shear. Most likely storm mode would quasi-linear
or broken cellular storms as storms lift east-northeast along the
frontal boundary. Medium-range Real-time AI NWP Convective Hazard
Forecast models (Pangu, FengWu) paint 5% to 15% probabilities
Tuesday 12Z to Thursday 12Z as a result.

Confidence decreases further through midweek as high pressure
attempts to drive a back-door cold front across the local forecast
area, forcing highest confidence along our southern periphery in
northeast Iowa. Given a sharp cutoff in precipitation and storms
expected, should this frontal boundary push/sag north/south, local
PoPs will require additional adjustment.

Cooler Through End Of Week, Weekend Storm Chances:

Canadian high pressure sagging southeast through the end of the week
ushers in a cooler, drier airmass before a passing low advecting
precipitation and storm chances through the weekend returns and
persists Upper Mississippi River Valley storm/precipitation
chances.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 550 AM CDT Mon Aug 10 2026

Fog and low stratus has overspread much of the Upper Mississippi
Valley this morning with widespread MVFR to LIFR conditions present
across the region. These conditions will continue for the next few
hours, gradually dissipating after sunrise. VFR conditions will
prevail after that with light winds out of a general easterly
direction. An area of rain of showers and storms is expected to
move into the area late in the period. There was high enough
confidence to include a prevailing group for KRST but not at
KLSE just yet as the bulk of the precipitation arrives after the
end of the 12Z cutoff. Have included a PROB30 at KLSE for now
to cover this activity.


&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Dense Fog Advisory until 10 AM CDT this morning for WIZ017-029.
MN...None.
IA...None.

&&

$$

DISCUSSION...JAR
AVIATION...Barendse