textproduct: La Crosse

KEY MESSAGES

- Light rain chances increase for early this morning and then continue into the afternoon with the highest chances (40-100%) for areas west of the Mississippi River. Small rain chances (up to 20%) then continue for the area into Sunday morning.

- After a dry Sunday night into Monday night, rain chances return on Tuesday and continue into Wednesday.

- Near-normal temperatures persist into next week with highs in the 60s to lower 70s.

DISCUSSION

Issued at 1235 AM CDT Sat Sep 26 2026

Today

A shortwave trough will eject northeast through the Upper Mississippi River Valley. The strongest forcing and moisture will be located west of the Mississippi River. While the CAMs are showing that the showers will decrease their coverage as they move east toward the Mississippi River, the synoptic forcing and 850 mb moisture transport look to be strong enough to produce at least some light rainfall totals through the morning and into the mid-afternoon. Due to this, increased the rain chances into the 60-100% range during this time frame.

High temperatures will be in the 60s. Due to the rain and cloud cover, the coolest high temperatures (lower 60s) will be west of the Mississippi River. Meanwhile, western and central Wisconsin will see high temperatures in the mid- and upper 60s.

Tonight and Sunday

As the shortwave trough continue to move northeast into a ridge of high pressure over the Great Lakes, there will be frontolysis along the surface front and dry southeast winds will advect drier air into the region for tonight and Sunday morning. This should reduce the shower coverage to isolated.

Low temperatures tonight will range from the mid-40s to mid-50s. High temperatures on Sunday will be in the mid-60s.

Sunday night and Monday night

High pressure over the Great Lakes will keep the area dry from Sunday night into Monday night.

Low temperatures on Sunday night and Monday night will range from the mid-40s to mid-50s. The coolest temperatures will be in central and north-central Wisconsin. High temperatures on Monday will be around 70 degrees.

Tuesday into Wednesday

A northern stream shortwave trough will move through the region. This system looks to be rather progressive, so this may result in lesser rainfall than previously forecast. There is a 50-80% probability of a half-inch or greater and a 30-65% probability of 1 inch or greater in the NBM.

High temperatures on Tuesday and Wednesday will range from mid-60s to around 70. Low temperatures on Tuesday night will be in the 50s.

Thursday into Friday

Still plenty of uncertainty on how far north the remnants of Polo will get. A few ensemble members suggest that there might be a PRE (Predecessor Rainfall Event) south of Interstate 90. A third of members suggest that a weakening surface low and its associated warm front may move into the region. Meanwhile, the other members keep the area dry. The NBM currently has the probabilities of an inch of rain or greater up to 40%.

High temperatures on Thursday and Friday will be in the mid-60s. Low temperatures on Thursday night will range from the mid-40s to lower 50s.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1235 AM CDT Sat Sep 26 2026

Primarily VFR conditions are expected areawide overnight although similar to the past few nights, patchy mist/fog may be able to develop in some of the valleys and low lying areas (20-30%) though near surface dry air and upper level clouds should keep impacts minimal.

Showers begin to move into the region from the west towards daybreak. Confidence is high that areas west of the Mississippi River will see rainfall throughout the day (70-90%) though showers will be light and visibilities are expected to remain VFR. However, MVFR ceilings associated with the showers also move into the region, impacting those sites primarily west of a KRST to KCCY line. Much drier air across Wisconsin should largely inhibit rainfall east of the Mississippi River (10-20%) where VFR conditions are expected throughout the TAF period. Otherwise, southeast winds continue across the region, generally at 5-10KT with gusts of 15-20KT west of the Mississippi River this afternoon.

ARX WATCHES/WARNINGS/ADVISORIES

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