textproduct: La Crosse

KEY MESSAGES

- Near to above normal temperatures with drier conditions for early this week with high temperatures rebounding into the mid 30s by Tuesday and Wednesday.

- Next widespread precipitation chance (60 to 80%) is Wednesday night into Thursday. Precipitation will start as rain then switch to widespread snow through Thursday.

DISCUSSION

Issued at 224 AM CST Mon Dec 15 2025

Today-Wednesday: Warmer and Drier

A nice break from the active weather is in store for the early portion of this week as warmer temperatures are expected. Currently, southwest flow is pushing warmer air northward and will help to increase temperatures into the mid and upper 20s today. Compared to previous forecasts, this early week was going to have ridging in place, however the upper level flow has become more zonal. This will allow for a shortwave trough to dip down into the northern portion of the Upper Midwest on Tuesday night. The precipitation with this wave is expected to stay in northern Wisconsin and both GEFS and EPS members show this as well as no members have precipitation forecasted for Taylor County. After this wave moves through, warm southwesterly flow returns and highs on Wednesday get into the mid to upper 30s.

Wednesday night-Thursday: Rain/Snow?

Heading into Wednesday night, another shortwave and associated low pressure system shift into the northern Plains and Upper Midwest. Ensemble cluster analysis from the 00Z LREF have most members pushing the low over Lake Superior, however there is about 40% of members, mainly the GEFS and GEPS that have the low slightly south. One of the clusters, includes 30% GEFS and about 10% ENS, depicts this low crossing over northern Wisconsin and in that scenario, we would be colder a little quicker than the other ensemble clusters suggest. QPF with this system is generally in the 0.1 to 0.2" range. The LREF probability for greater than 0.1" supports this forecast as there is a 50 to 80% chance for this to occur. The potential precipitation type uncertainties with this system have mostly gone away as temperatures stay above freezing as the low approaches and the first wave of moisture arrives and then as the cold air advection moves into the area, a shift to snow will occur. One thing to note is that with the first wave of precipitation, while it will start out as rain, depending on rain rate and degree of cooling, snow could overtake the rain as the dominant precipitation type. This is shown in GFS BUFKIT soundings as the initial wave is rain and by the end of the first wave, snow replaces the rain for the last couple of hours due to the cold air advection and precipitation rate. Measurable snowfall is likely with the wrap around precipitation associated with this low, however it is only low amounts. Based on LREF probabilities of greater than 0.3" there is a 40 to 70% chance for this amount to occur along and north of I-90.

After Thursday, zonal flow remains the dominant pattern and results in little temperature variations heading into the weekend with highs generally in the 20s to low 30s. Off and on precipitation chances (15 to 25%) linger into early next week with this flow pattern.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 532 AM CST Mon Dec 15 2025

VFR to high-end MVFR conditions currently present across the region. Gusty southerly winds will continue on their downward trend through the morning hours with gusts gradually diminishing at the RST terminal by mid morning. Winds are also expected to veer to a more west/southwesterly direction by the afternoon with winds becoming light at less than 8 kts after 21Z. Through the evening and into the overnight hours, a batch of IFR/LIFR stratus and fog is expected to develop across much of the Upper Mississippi Valley amid continued warm air advection over a dense snowpack. With increasing confidence among guidance, have lowered visibilities and CIGs for the KRST terminal to include a few hours of LIFR conditions late overnight. KLSE will likely see visibilities drop to the IFR range for a couple hours with largely MVFR visibilities through the overnight hours. Conditions should start to improve by daybreak with more significant improvement expected after 12Z.

ARX WATCHES/WARNINGS/ADVISORIES

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