textproduct: La Crosse

KEY MESSAGES

- Near seasonable temperatures expected this weekend with low confidence for light precipitation from southeast Minnesota into west-central and central Wisconsin.

- Strong to severe storm chances increase Monday, initially lower confidence through the morning hours affecting subsequent locally higher severe potential through the afternoon and evening. Primary hazards of large hail and damaging winds with secondary hazard of tornadoes.

- Colder through next week with slightly below normal temperatures potentially nearing freezing overnight for some by midweek.

DISCUSSION

Issued at 118 PM CDT Fri Apr 24 2026

Near Seasonable Weekend & Low, Light Rain Chances For Some:

Slightly warmer temperatures than today (Friday) through the weekend into early next week expected as the closed upper level low straddling the International Border over Montana and North Dakota slightly retreats north into southern Canada through Saturday. Resultant return flow ekes into and grazes the Upper Mississippi River Valley through Saturday with light precipitation chances focused along a low level stretching axis slowly progressing northeast along locally northwestern peripheral counties from southeast Minnesota into west-central and central Wisconsin late Saturday afternoon into early Sunday morning. Narrow, confined nature of meager moisture returns limits coverage, overall impacts, and QPF amounts. Therefore, while have continued with limited PoPs, will be initial forecast detail requiring forecast amendments in coming forecast issuances.

Strong to Severe Storm Chances Monday:

After the meager low progresses northeast along the aforementioned axis of dilatation through early Sunday morning, return flow reinvigorates through the Central Plains as the closed upper level cyclone on GOES WV imagery lifts northeast due to incoming subtropical jet streak seen over the eastern Pacific on GOES derived upper level winds. Current confidence in lifting of the subsequent lingering troughal appendage northeast through the Upper Midwest brings initial storm chances in locally western counties through Monday morning on the precursor warm frontal boundary as ancillary linear storm mode along a subsequent potential cold frontal boundary through the afternoon and evening.

Overall confidence limited by duration of morning storms potentially accessing meager instability in lingering narrow filament of increased moisture through the weekend near the forecast area affects subsequent building of local instability. Furthermore, variations in track of low center seen from central Wisconsin to the Minnesota International Border in the EPS (24.06Z) and from northern Illinois to the Minnesota International Border in the GEFS (24.12Z). The more northern track, a persistent signal in the EPS over recent runs compared to the GEFS which only begun to tie into this solution in the last couple of runs, advects a more moist and unstable air mass farther north through the local forecast area, increasing local storm chances. A more southern track could limit local storm coverage and duration as the unstable warm sector could only graze the southern half of the forecast area. Although, enhanced low level vorticity within the low center could exacerbate available shear and subsequent local severe hazards should it traverse the local forecast area.

While ancillary cold frontal progression causing linear storm mode through late afternoon evening would be the higher confidence scenario for locally heightened storm severity, LREF sounding plumes suggest clockwise turning low level hodographs locally through the morning hours; raising concern for initial severe hazards to include isolated tornadoes should storms manage to become surface based however challenging the endeavor. Low confidence scenario but should be mentioned nonetheless. Similarly, current confidence for large hail and damaging winds with ancillary cold front passage primarily across southern half of the forecast area through the afternoon and evening in current forecast hour also requires additional scrutinizing for potentially weaker tornadoes where QLCS breaks form. Overall, further details and hazards requiring further addressing in coming forecast packages.

Colder Through Mid Next Week:

A Canadian Polar airmass attempts to poke south through the Upper Mississippi River Valley through the middle of next week, raising concerns for frost/freeze initially Tuesday night locally. While initial timing of colder remains dependent on timing of trough ejection, synoptic agreement for colder air settling into region through the middle of the week increases some confidence for near freezing overnight temperatures by the end of the week. Coldest solution in the GFS/GEFS advects the 850mb 0C isotherm through most of Iowa by the end of the work week. Irregardless, current forecast confidence (80%) for slightly below normal temperatures through the end of April.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1232 PM CDT Fri Apr 24 2026

As a shortwave trough moves northeast through western and northern Minnesota late tonight and Saturday morning, mid- and high clouds will impact KRST. Meanwhile, KLSE will remain mostly clear.

ARX WATCHES/WARNINGS/ADVISORIES

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