textproduct: La Crosse

KEY MESSAGES

- Warmer temperatures today and Thursday with highs in the 70s to near 80 in some spots areawide. Slightly cooler temperatures for Friday through early next week with highs in the 60s for most.

- Showers and storms very likely (80-95%) Thursday evening and overnight. Strong to severe storms cannot be ruled out during this period, however confidence remains low in this potential.

DISCUSSION

Issued at 1155 PM CDT Tue Apr 21 2026

Today - Thursday: Warm, Shower and Storms Likely Thursday Evening

Upper-level ridging remains the main synoptic feature over the region today with southerly surface flow for much of the afternoon hours today and into Thursday. As a result, NBM inter-quartile range remains fairly consistent on keeping highs in the middle 70s to lower 80s across the local area. The main feature to watch over the next few days comes in the form of an upper-level trough that pushes into the Northern Plains with an attending surface low. As this surface low pushes northward, an associated surface cold front ejects eastward towards the local area. As this occurs, ample lift will be in place for showers and storms to develop along the front as it pushes eastward into the local area. MLCAPE values in the recent RAP over 1000 J/kg would suggest storms will be likely, however the main forecast question that remains is the severe potential. Currently, much of the shear profiles are in the low- levels with ample hodograph curvature in the 0-1km layer ahead of the front. However, this quickly becomes messy suggesting deep-layer storm organization would be a struggle in this regime. As a result, convective mode along the front in this setup would more likely favor pulse-like updrafts that push along the front as it moves into the local area. That being said, if you can manage to sustain an updraft for a longer period, you could perhaps manifest some bowing segments or a deep enough updraft to produce marginally severe hail with mid- level lapse rates approaching 7 C/km.

Otherwise, probabilities for at least some healthy rainfall are increasing in the grand ensemble (GEFS/EC/Canadian ensemble) where it has medium to high probabilities (40-65%) for rainfall amounts of over 0.5", even some low-end probabilities (10-30%) for over 1" of rain with these showers and storms. However, with most of the rivers with rises being east of the Mississippi River and these higher probabilities in the southeast MN and northeast IA, not expecting any additional flooding concerns with this round of rain at this point.

Friday - Early Next Week: Cooler, Precipitation Potential Monday

As we head into Friday, cold air advection behind the aforementioned cold front will drop temperatures to near normal with highs generally in the 60s for much of the region. With the trough closing off into a closed low and pushing northward, this will keep reinforced seasonable conditions across the area through the weekend. However, as we head into Sunday night and Monday deterministic guidance generally agrees on pivoting a fairly pronounced shortwave trough towards the region. As this move into the Upper Midwest, a fairly pronounced surface low pushes into the region with a fairly pronounced deformation zone and stratiform rain shield. As a result, the grand ensemble (GEFS/EC/Canadian ensemble) has very high probabilities (80-95%) for measurable rainfall with even medium probabilities (20-40%) for rainfall amounts over 0.75" through Monday evening.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1235 AM CDT Wed Apr 22 2026

VFR conditions prevail through the TAF period. A few high level clouds around 25kft linger through the overnight then some mid level clouds around 15kft move into the area later this morning and linger through the rest of the day. Light and variable winds overnight shift to southeast winds by mid morning. These winds increase this afternoon with sustained winds of 10 to 20 mph with gusts approaching 25 mph west of the Mississippi River.

HYDROLOGY

Issued at 1155 PM CDT Tue Apr 21 2026

The Yellow River at Necedah is expected to fall below minor flood stage this morning. Additionally, the bulk of the heaviest rain is expected to fall west of the Mississippi River on Thursday. As a result, not currently expecting to see rises back into flood stage at this time.

ARX WATCHES/WARNINGS/ADVISORIES

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