textproduct: La Crosse

KEY MESSAGES

- Showers and storms (80-95%) this evening and overnight. A few strong to severe storms cannot be ruled out. Widespread rainfall amounts of 0.75" to 1.25" are likely with localized amounts of up to around 2" possible.

- Warm temperatures today with highs in the 70s to lower 80s give way to more seasonable temperatures for Friday and into the weekend with highs in the 60s for most.

- Additional precipitation likely (60-80%) for Sunday night and into Monday.

DISCUSSION

Issued at 1159 PM CDT Wed Apr 22 2026

This Evening & Overnight: Showers and Storms Likely, A Few Strong to Severe Possible

A closed upper-level low sitting near the border of Montana and Saskatchewan will continue to meander through southern Canada over the coming days, while this occurs a shortwave trough is pivots in the Northern Plains around this feature this afternoon and into the overnight. With this shortwave passage to our west, an attending surface low occludes into Manitoba and pushes a surface cold front towards the local area. A couple different forcing mechanisms seem apparent for storms today, the first of which being a ribbon of theta-e advection during the late afternoon and early evening hours and a second being the aforementioned cold frontal passage later into the evening and overnight. Overall, the environment is fairly questionable as deep-layer shear is relatively absent with messy middle and upper-level hodographs due to the upper-level jet streak lagging behind the frontal passage. As a result, shear profiles are relatively low-level dominated with some low-level hodograph curvature present in the RAP/HRRR across the region. Consequently, would expect storm mode to be quasi-linear with pulse-like updrafts along the various forcing mechanisms as depicted in much of the CAMs. Would think at least some hail up to quarter sized cannot be ruled out with some stronger cores and mid-level lapse rates of around 7 C/km, however these would likely not be long lived. Additionally, with the aforementioned low-level hodograph curvature and 0-3km shear magnitudes of around 30 kts at times, cannot rule out a weak spin up or two. In any case, significant severe potential seems predominantly off the table as any severe threats that manifest would be hail to around quarter sized, marginally severe wind gusts (up to around 60 mph) or perhaps a weak tornado.

Could see some fairly impressive rainfall with these storms though as the recent HREF has some respectable probabilities (20-60%) for rainfall amounts over 1 inch across the local area with 90th percentile values approaching 2 inches in some spots. So widespread amounts of 0.75" to 1" seem plausible with upwards of 2 inches where storms repeat over the same locations. Would not expect any widespread flooding concerns with this but could see some ponding in low-lying areas or rises on rivers in smaller basins that receive multiple rounds of rain.

Friday - Sunday: Seasonable Temperatures

As we head into Friday and the weekend, zonal flow behind the cold air advection regime with the aforementioned cold front will usher in more seasonable temperatures for Friday and into the weekend with highs likely in the 60s for much of the area. With skies clearing due to some weak high pressure overhead and lighter surface winds on Saturday morning, cannot rule out some potential for patchy frost in north-central WI with lows falling into the middle to upper 30s.

Sunday Night - Early Next Week: Precipitation Chances Return

By Sunday night and into Monday, our next feature comes in the form of a fairly pronounced shortwave trough pushing towards the local area in southwesterly 500mb flow. As this pushes towards the region, a fairly pronounced surface low ejects towards the Upper Mississippi River valley across deterministic guidance. Overall, confidence is very high for measurable rainfall during this period with high probabilities (80-95%) in the grand ensemble (GEFS/EC/Canadian ensemble). There is even already some medium probabilities (50-70%) for rainfall amounts of over 0.5" during this period as well within the grand ensemble (GEFS/EC/Canadian ensemble). The main point of uncertainty that remains is where the surface low tracks, a further north trajectory may introduce some instability into the region which could be more favored for convection, as opposed to a southerly track which would favor more of a stratiform rain setup. Overall, the grand ensemble (GEFS/EC/Canadian ensemble) has some low probabilities (10-30%) for 100 J/kg SBCAPE. So if a northern track occurs, could introduce some convection with a lower-end severe risk.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 547 AM CDT Thu Apr 23 2026

MVFR CIGS between 1500 and 2500ft will be moving into southeast Minnesota and northeast Iowa over the next few hours. While lowered CIGS between 3000 and 5000ft move into areas along and east of the Mississippi River later this morning, these MVFR CIGS will gradually move into western Wisconsin by the mid afternoon to early evening. Periodic showers and storms expected for today and into tonight beginning later this morning and early afternoon in southeast Minnesota and northeast Iowa. These storms move into western Wisconsin by the mid to late afternoon. MVFR to IFR visibilities will be possible under heavier rain. Southerly winds increase this morning and continue through the afternoon with sustained winds of 15 to 25 mph and gusts of 25 to 35 mph. These southerly winds shift to the northwest as a cold front moves across the region between 06 and 12Z.

ARX WATCHES/WARNINGS/ADVISORIES

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