textproduct: La Crosse

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.