textproduct: La Crosse

KEY MESSAGES

- Clusters of storms developing over southern Minnesota into western Wisconsin advance southeast this evening. Some storms may be severe and produce locally heavy rainfall of (1-3"), mainly west of the Mississippi River.

- Quieter weather for the remainder of the week with a 20-30% chance of afternoon storms for Thursday.

- Cooler for the end of the week with warmth returning early next week.

DISCUSSION

Issued at 100 PM CDT Wed Jul 8 2026

This Afternoon: Severe Weather and Heavy Rain Risk

A convective complex that moved through central Minnesota gradually decayed and shifted northward through the morning hours as it ran into a more stable airmass, with the back edge of the anvil shield serving as the trigger for new convective development around noon as return southerly flow streamed up through the Siouxland. These cells have already grown into a multi-cell complex with additional cells developing further upstream along I-90. Given the earlier initiation timeframe and continued convective debris lingering over the forecast area, concerns area shifting more towards a heavy rain threat vs. severe threat with these storms.

There looks to be a period before 00Z where storms could train along the I-90 corridor in southeastern Minnesota before the convective cold pools take over and propagate to the southeast, which should result in the convective complex sagging southward as well. Multiple runs of the HRRR through the day have been focusing the QPF axis of 1-3 inches (with some pixels of 4-5 inches) between I-35 and Highway 52 in southeast Minnesota and far northeast Iowa, an area that remains saturated from last week's deluge. Given these trends, have issued a flood watch for much of the area west of the Mississippi River through midnight tonight.

There severe threat remains on the table, but will probably be more focused west of the Mississippi River (maybe even closer to I-35) where there will be better recovery of the airmass. There is some southeastward elongation in the 1-5-km hodographs that could support some storms organization, but with cells already growing upscale into clusters, severe weather will likely be focused in narrow corridors where the convective cold pools can organize. As the storms become more outflow dominant in the evening, the severe weather threat should wane.

Thursday Afternoon: Scattered Showers and Storms

Cooler and slightly less humid air filters southward on Thursday in the wake of this afternoon's storms, but vertical thermal profiles will still support pulse convection during the afternoon with MLCAPE values of 1500-2000 J/kg and little to no inhibition. Shear profiles and forcing will be weak and therefore storms will struggle to organize. Very localized heavy rainfall of 1-2 inches would be the main threat with these storms given their slower storm motions.

Cool End to the Week, Warmer Next Week

Upper level ridging builds in for the weekend and into early next week, keeping the threat for rainfall at bay while at the same time pumping heat northward into the northern CONUS. At this point, the warmest temperatures are progged to be more over High Plains with the Upper Mississippi River Valley falling under a weak east to southeasterly flow under or just west of the surface high pressure reflection. This may act to temper temperatures and dewpoints compared to locations further west, though to the exact degree is less certain. Highs are still forecast to reach into the upper 80s to low 90s no matter how you slice the forecast, making it feel solidly like summer. The ridge flattens around midweek, but how fast it amplifies earlier in the week will dictate whether this flattening brings convection down into our region or if the storms stay to the north and we remain under the heat. The various ensembles groups remain in their respective camps on how this will unfold with no clear leaning one way or another.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1250 PM CDT Wed Jul 8 2026

Primarily VFR conditions continue through the next few hours with light southwest winds ahead of expected showers and storms that move northwest to southeast across the region this afternoon into tonight, generally in the 20z to 09z timeframe. That said, there are some storms have already developed along I-35 this afternoon. These storms are expected to bring heavy rainfall leading to MVFR/IFR ceilings and visibilities. Also can't rule out some strong gusty winds as they move through.

MVFR to IFR ceilings linger through the overnight hours behind the showers/storms. There is also the indication that patchy fog could develop across the region alongside these lower ceilings, but any fog that does develop should burn off fairly quickly through the morning hours. Confidence in fog impacts is currently not high enough to include at the TAF sites, but is something to monitor overnight. Winds gradually shift to the northwest through Thursday morning generally 10KT or less.

ARX WATCHES/WARNINGS/ADVISORIES

WI...None. MN...Flood Watch until midnight CDT tonight for MNZ086>088-094>096. IA...Flood Watch until midnight CDT tonight for IAZ008>011-018-019.