textproduct: La Crosse

KEY MESSAGES

- Periodic storm chances through the weekend. Any severe potential looks low at this time.

- Temperatures remain near normal with highs in the mid 70s to mid 80s through Thursday, then cool slightly for the weekend.

DISCUSSION

Issued at 135 PM CDT Tue Aug 11 2026

This Afternoon - Thursday: Storm Potential with Seasonable Temperatures

Storms from this morning shot off a boundary that went northeast through the CWA. This boundary helped to initiate some showers across western and central Wisconsin and continued to move northward. More showers and storms are possible this afternoon and evening along this boundary, however the chances are low (<15%). As we head into tonight and Wednesday morning, another MCS or line of storms is expected to form as a shortwave shifts down from the northern Plains into portions of the Upper Midwest. Due to this morning's MCS, the path for tonight's storms should stay mostly south of the forecast area with our southern tier of counties seeing the highest potential for showers/storms (20 to 40%). The RRFS solution has one of the more defined storm complexes and it impacts northeast Iowa. It is also one of the more northern solutions. Not to rule out the possibility of this happening, but this morning's MCS went a little further south than anticipated so the thinking is that Wednesday morning's would follow suit. In addition, a boundary should form to the north of the storm complex after it moves through, leaving a low potential (15 to 25%) for scattered showers and storms mostly north of I-90 during the afternoon and evening.

By early Thursday morning another shortwave moves down into the region. At the same time, a low forms in the central Plains. This low will shift towards the northeast as southwest flow increases aloft and the shortwave will move southeastward. This two systems look to meet somewhere between central Iowa and southern Minnesota. This area would have the highest chance for showers and storms to occur. Currently there is still a bit of uncertainty on where exactly showers and storms pass through for Thursday morning. Will get better details as we get closer. With zonal flow anticipated through Thursday, high temperatures should stay close to normal, with highs in the mid 70s to mid 80s.

Friday - Early Next Week: Periodic Storm Chances

Heading into the weekend guidance is in good agreement on the ridge shifting over the eastern US. This in turn will put our region in west to southwest flow as the ridge axis should stay to our southeast. The position of this ridge will help keep our temperatures slightly below normal with highs in the low 70s to low 80s through the weekend. With a good southwest fetch of moisture from the Gulf from Friday into Sunday and PWATs in the 97.5 to 99th percentiles (1.75 to 2.25") there is a heavy rain potential during the period. Both the GFS and ECMWF have a warm front that brings an initial band of showers and storms on Friday night/Saturday morning followed by another shortwave for Saturday evening. There is already an EFI signal of 0.5 to 0.65 indicating that this rain event would lean on the higher side of climatology. WPC has gone ahead and issued a slight risk for excessive rainfall for Saturday due to these parameters.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1225 PM CDT Tue Aug 11 2026

A few pockets of MVFR ceilings have lingered throughout the morning hours, but have begun to dissipate with heating which will result in VFR conditions prevailing through the rest of the afternoon. A few isolated showers and perhaps a storm could develop north of I-94 this afternoon and evening, but this potential is low, only 10-20% per the 11.12z HREF/REFS. Overnight, some concern for fog exists given humid conditions and rainfall from this morning, but increasing mid-high cloud cover around 12-15kft could limit the amount of cooling seen across the region. This would act to keep fog potential confined to lower lying areas and to those closer to and east of the Mississippi River, though if cloud cover remains at bay, fog potential would become more widespread. There's also some indication of additional showers/storms along/south of Highway 18 across northern Iowa/southwest Wisconsin Wednesday morning though probabilities of this are also on the lower end (20-30%). Otherwise, winds remain light and variable over the next 24 hours.

ARX WATCHES/WARNINGS/ADVISORIES

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