textproduct: La Crosse

KEY MESSAGES

- Light rain chances continue through Sunday morning with the highest chances (40-70%) west of the Mississippi River through sunrise on Sunday.

- After a dry Sunday night through Monday, rain chances return on Tuesday through the rest of the week.

- Temperatures will remain seasonal in the 60s to 70s.

DISCUSSION

Issued at 120 PM CDT Sat Sep 26 2026

This afternoon through Sunday: Scattered Light Rain Showers

An H500 shortwave trough is moving over the region today and is aiding in developing light rain showers across Iowa and Minnesota. Most of the activity today should stay to the west of the Mississippi River, where the higher moisture and stronger forcing are located. Any rain amounts for today should be very light, the HREF has around a 20-50% chance for rainfall to exceed a quarter inch near I-35 and into the far western portions of the CWA by Sunday morning. Scattered showers may develop further east overnight into Wisconsin, but amounts should remain light as the moisture axis shifts slowly to the east. Rain showers should decrease in coverage by late Sunday morning as synoptic scale lift decreases over the Upper Midwest. Temperatures both today and Sunday should mainly be in the 60s, with some locations reaching the lower 70s.

Monday and Tuesday: Dry Monday - Rain Chances Return Tuesday

The forecast area will be in between two different weather systems to start the next work week. A low pressure system will continue to remain over the northeastern US and a trough will dig south across the western CONUS. Pleasant conditions overall are expected on Monday with temperatures in the lower 70s and partly cloudy skies with very little wind. As the aforementioned trough continues to dig south over the Desert Southwest on Tuesday, moisture should surge northward out ahead of this feature. Sufficient PVA supplied by shortwaves embedded in the upper level flow should lead to rain showers and potentially thunderstorms developing across the region on Tuesday into Wednesday morning. Just how much rain we receive from the initial bands of showers and storms will be dependent upon the moisture quality going into Wednesday morning. The 90th percentile rainfall amounts from the LREF do indicate the potential for some locations to see an inch of rainfall or more, but confidence is low at this time.

Rest of Next Week: Daily Rain Chances May Continue

The remainder of this forecast period is highly uncertain as it will depend upon the evolution of the low pressure center associated with the synoptic scale trough as well as how this feature combines with the remnants of now Hurricane Polo. Ensemble guidance along with deterministic forecast models indicate plenty of differences in timing and location in the axis of better rain chances for Wednesday and beyond. This is shown really well in the NBM PoP values, which keep at least low to medium (20-50%) chances for rain through Friday. The current expectation is that the heaviest rainfall will stay south of the Upper Midwest, but there are outlier solutions that produce 2+ inches of rainfall during the later half of this upcoming week. Temperatures are forecast to remain near average to end the month of September.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1249 PM CDT Sat Sep 26 2026

Low-level VFR cigs to perhaps some MVFR cigs (10-30% chance in the recent HREF) are expected early in the TAF period, mainly west of the Mississippi River as some light precipitation moves through the region. Low-level cigs will persist overnight with eventual MVFR reductions at KRST by the overnight. Additional showers and storms will be possible as hinted by some of the CAMs with some weak instability overnight. Consequently, have maintained a prob30 at KRST into the early morning hours for some shower potential.

ARX WATCHES/WARNINGS/ADVISORIES

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