textproduct: La Crosse

KEY MESSAGES

- Periodic bouts of showers and storms are expected through next weekend. These may produce heavy rain and severe weather at times. If severe weather does occur, damaging winds would be the main threat. Any flooding will be highly dependent upon whether storms can repeatedly move over the same areas.

DISCUSSION

Issued at 111 PM CDT Sun Aug 9 2026

This Afternoon and Evening

Rain-cooled air in the wake of the morning linear mesoscale- convective complex will greatly limit the redevelopment of showers and storms across much of the Upper Mississippi River Valley through this evening. The latest CAMs are in agreement with this for much of the area. The only areas where they are showing redevelopment late this afternoon and evening is north- central Wisconsin and far southern Wisconsin. These areas will have a residual convective outflow boundaries from this morning and they have a much better chance for recovery.

Currently have high temperatures ranging from the mid-70s to lower 80s. With broken clouds and rain-cooled air from this morning's convection, I am a bit concerned that these temperatures might be a bit too warm.

Low temperatures tonight will range from the mid-50s to around 60 along and north of Interstate 94, and in the mid-60s elsewhere.

Monday

A front will remain primarily south across the Mid-Mississippi River Valley on Monday. This front will be the focus for development of showers and storms on Monday. In our area, this precipitation would be located across northeast Iowa and southwest Wisconsin. With the better instability (2-3K J/kg) and shear (0-3 km shear around 40 knots) to the south of our area, not anticipating any organized severe weather.

High temperatures on Monday will be in the lower and mid-80s.

Monday Night into Tuesday

The 09.12z models are in good agreement a mesoscale convective complex will develop across the Dakotas on Monday evening and then move southeast across either the Upper and/or Mid- Mississippi River Valleys overnight on Monday night and Tuesday morning. With 40-50 knots of uniform winds in the mid-levels, there could be the potential for this system to provide a wind threat. This will be highly dependent on the depth of the nocturnal inversion and the amount of DCAPE available.

On Monday night, low temperatures will range from the mid-50s to around 60 along and north of Interstate 94, and in the mid-60s elsewhere. High temperatures on Tuesday will be in the lower and mid-80s.

Tuesday night into Next Weekend

A front will oscillate north and south across the Mid- and Upper Mississippi River Valleys from Tuesday night into next weekend as shortwave troughs move along the northern periphery of a ridge of high pressure over the Southern Plains and southeast US. The better rain chances will be south of Interstate 94. With strong unidirectional flow in the mid- levels, there could be the potential for severe weather at times.

High temperatures will be near normal on Wednesday and generally below normal from Thursday into Sunday. Low temperatures will range from the mid-50s to mid-60s.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 639 PM CDT Sun Aug 9 2026

VFR conditions give way to MVFR and eventual IFR conditions overnight as fog develops across the local area. Probabilities in the NBH favor developing fog overnight with IFR reductions possible (30-50%). Consequently, have opted to maintain 1SM reductions overnight and into the morning hours on Monday. Cannot rule out some 1/4SM as the recent HREF has some low-end probabilities (20-30%) for it, however confidence remains too low to include in the TAF at this time. Fog will eventually clear around mid-morning as diurnal mixing aids in drying the boundary layer. Otherwise, winds will remain light and under 5 kts over much of the TAF period.

ARX WATCHES/WARNINGS/ADVISORIES

WI...None. MN...None. IA...None.