623
FXUS63 KARX 291059
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
559 AM CDT Wed Jul 29 2026

.KEY MESSAGES...

- Potential impacts from wildfire smoke primarily west of the
  Mississippi River initially this evening and overnight.

- Precipitation chances increase through Friday from west to
  east with local confidence decreasing in higher rainfall
  amounts (1"+) and strong storms (<5%).

&&

.DISCUSSION...
Issued at 1231 AM CDT Wed Jul 29 2026

Potential Near Surface Smoke Impacts Into Thursday:

A stout area of anticyclonic flow over the Upper Mississippi
River Valley will cause a mostly persistent forecast until
Friday when precipitation chances increase from west to east.
Main impact concern through midweek will be potential near
surface smoke causing poor air quality. Tuesday satellite
imagery exhibited the off- surface increased vertically
integrated smoke over and upstream of the forecast area with the
anticyclonic flow expected to sink particulates to the surface
Wednesday evening into the nighttime hours (HRRR 28.18Z).
Location of high pressure in relation to the local forecast area
will determine extent of local impacts with current confidence
for highest impacts primarily west of the Mississippi River
Valley.

Precipitation Chances Friday Into Saturday:

A deepening extratropical cyclone will slide east-southeast
through the Northern to Central Plains Thursday night through
Friday, bringing precipitation chances across the Upper Midwest
as it passes. Current confidence in the low`s progression
jogging south as it approaches the Upper Mississippi River
Valley abates higher confidence for higher precipitation
probabilities and unstable air west and south of the local
forecast area. Although, without this southern shunt, locally
increased rainfall amounts and instability is possible. While
outlying, select EPS members suggests 3"+ QPF in select local
areas with a more northern, moist solution.

Current long term global ensemble confidence keeps the near
normal low level temperatures over the forecast area until early
next week when low level theta e advection ramps up.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 600 AM CDT Wed Jul 29 2026

Minimal aviation impacts are expected through the TAF period as
high pressure moves through the region. Calm to light winds this
morning become southerly to southwesterly by the afternoon, but
remain 10KT or less. Diurnal cumulus 4-6kft is expected to
develop late this morning into the afternoon hours along with
the low potential for an isolated shower or storm (5-10%), most
favorable along/north of I-90. Near-surface and vertically
integrated smoke are both expected to increase across the region
this afternoon, lingering into the evening hours which will act
to reduce visibilities.

&&

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

&&

$$

DISCUSSION...JAR
AVIATION...Falkinham