textproduct: La Crosse

KEY MESSAGES

- Less humid today and turning breezy this afternoon, especially north of I-94 with gusts approaching 35 to 40 mph.

- Showers and some storms develop north of I-90 tonight with greatest chances (60-80%) north of I-94. Rain chances then shift southward during the day Saturday.

- Big pattern shift arrives Sunday with cooler than normal conditions lingering through much of next week.

DISCUSSION

Issued at 1258 AM CDT Fri Jun 12 2026

Less humid today and turning breezy this afternoon

A less volatile weather pattern is in store as the week draws to a close. The biggest tangible change will be considerably lower humidity, making it feel much more pleasant. Upper level flow will turn more zonal today as troughing slips off to the east. Steep low level lapse rates this afternoon will allow for very deep mixing to around 750 to 700mb. This will promote breezy westerly winds, potentially mixing down gusts approaching 35-40+ mph across our northern counties per forecast soundings (50% chance). Thinking the RAP/HRRR are over-mixed with 45-55 kts at the top of their mixed layers all the way up to 650-600 mb.

Showers and some storms return tonight north of I-90

Heading into this evening, MSLP reveals a col developing over the Upper Mississippi Valley at the intersection of surface ridging and troughing. A quasi-stationary front will lay out just northwest of the forecast area. Associated frontogenetic forcing, combined with weak moisture transport on the nose of a low level jet, will promote developing showers and perhaps a few storms over southern Minnesota into northern Wisconsin this evening. Instability will be diminishing, but there looks to be at least a few hundred J/kg MUCAPE that could support some rumbles of thunder. Clark and especially Taylor counties will be most prone to the rainfall, where the 12.00Z HREF has 40-90% probabilities for a quarter inch or more and 30-60% probabilities for a half inch or more by Saturday morning.

Shower and storm chances shift further south on Saturday

During the day Saturday, upper level troughing overhead will gradually deepen, nudging the front southward. Daytime instability building south of the front will favor additional shower and storm chances, especially by afternoon. The forecast currently calls for 40-60% PoPs from northeast Iowa into central Wisconsin, but those values are likely to increase as we get closer in time. The NBM has highest rainfall amounts across far northeast Iowa and far southwest Wisconsin where the 90th percentile is between 0.75 to 1".

Big pattern shift next week to considerably cooler than normal

A pretty dramatic pattern shift is in store for Sunday as deep upper troughing takes hold over the CONUS. High temperatures will likely struggle to break 70 in some areas despite abundant sunshine. The long range ensembles (GEFS/ENS/GEPS) mean max temperature Sunday afternoon is generally in the mid 60s with the 90th percentiles generally in the upper 60s to around 70. This continental polar airmass will linger but slowly moderate through the middle of next week with highs gradually warming through the 70s. Gulf moisture begins to return Tuesday into Wednesday in short conjunction with some shortwave energy. This will bring the next chance of showers and some storms toward the middle of the week.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 545 AM CDT Fri Jun 12 2026

VFR conditions expected for the next 24 hours. Westerly winds will pick up in the next few hours with gusts at the terminals to between 20-30 kts continuing into the afternoon before tapering off this evening. Winds will then back to a more south/southwesterly direction with speeds between 5-12 kts overnight. Rain chances increase overnight for areas north of I-90 but they generally stay north of the terminals and probabilities of precipitation remain too low at this time to warrant a PROB30 for either LSE or RST with this package update.

ARX WATCHES/WARNINGS/ADVISORIES

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