textproduct: La Crosse

KEY MESSAGES

- Rain shower and thunderstorm chances increase on Saturday with another round on Sunday and some of the storms on Sunday could be strong to severe.

- Daily chances for rain continue each day next week with temperatures near to slightly above average.

DISCUSSION

Issued at 1230 PM CDT Fri Aug 28 2026

This Afternoon Through Sunday: Showers and Thunderstorms Return

Another beautiful weather day will occur this afternoon across the Driftless region! Very similar to the last few days, a light breeze will be in the air and temperatures will rise into the upper 70s to low 80s for highs this afternoon. Today would be a great day to get outdoors and enjoy the nice weather before the potential for rain returns as well as warmer temperatures.

Speaking of the rain potential, northerly flow aloft today begins to become more northwest to west this evening into Saturday morning. This change in the upper level flow opens the door to shortwave troughs to ride the top of the ridge through the weekend. Strong mid level theta-e advection will occur out ahead of the first disturbance that is progged to move over the Upper Midwest beginning Saturday morning. Widespread showers should form as a result and the system should move from west to east during Saturday morning into the afternoon. There may be just enough instability present for a few storms to form, but they will be few and far between. The 28/12z HREF mean PWAT values are near the climatological max based on sounding data from KMPX, so the rain showers may be efficient rain producers, especially with any stronger cores/storms that may form. Even though there could be heavy rain at times, flooding is not expected as the system will be fairly quick moving.

The potential for rainfall on Sunday is more uncertain as there are timing and mesoscale differences in the forecast guidance. Right now there are off and on chances throughout the day given the uncertainty. Some forecast models do depict the potential for some storms to become strong to severe on Sunday afternoon into the evening, but confidence in that scenario panning out are very, very low right now. A majority of guidance depicts strong WAA at H850 which would lead to strong capping, but there are a few models hinting that the WAA may be overdone. If the severe storm threat were to pan out, damaging wind gusts and large hail would be the primary hazards. Temperatures on Sunday could be quite warm in response to the increased low level temperatures with forecast highs in the mid to upper 80s.

Next Week: Daily Rain Chances with Warm Conditions

There is fairly good consistency to the expected upper level pattern for next week, with the center of high pressure sitting over the southeast and troughing across the northwestern CONUS. The northern extent of the ridge is the main area of uncertainty right now and will play a large factor in the weather for next week. The GFS/GEFS are currently an outlier in the ensemble model suite and they are indicating near record breaking heat for a few days next week with highs in the 90s each afternoon. These temperatures appear to be well overdone as EC/Canadian ensembles are cooler and the AIGFS/AI Euro are also leaning that way. In fact, the GEFS mean for high temperatures in the middle to later half of next week is 5 degrees or higher for temperatures compared to the EC/Canadian ensemble means. So all that is to say that the NBM blended temperatures, which are currently in the forecast, may be skewed slightly on the warmer side due to the apparent warm bias from the GEFS. There is fairly good agreement that Monday will be a warm day, with highs in the mid to upper 80s. Beyond Monday is where the guidance really begins to diverge.

With the flow over the Upper Midwest becoming westerly through the next work week, this should continue the potential for nearly daily chances for showers and thunderstorms. There is some concern that there may be chances for heavy rain in the middle of next week that could lead to some flooding concerns, but due to the variance in the upper pattern, confidence in location, timing, etc. is low at this time.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 650 PM CDT Fri Aug 28 2026

VFR conditions are expected for much of tonight with widespread rain showers (>90% chance) capable of MVFR visibilities (and ceilings north of an EAU to ISW line) moving through mainly during the morning hours on Saturday. MVFR ceilings may linger into the afternoon north of this aforementioned line, but much of the area should be VFR for the afternoon. Southerly winds increase through the night with gusts of 20-25kts for much of the day on Saturday. There is a window of opportunity for gusts of 30-40 kts Saturday morning west of the Mississippi River in conjunction with these showers, but these stronger winds will be very transient in space and time.

ARX WATCHES/WARNINGS/ADVISORIES

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