textproduct: La Crosse

KEY MESSAGES

- There are additional chances (30-50 percent) for showers and storms this evening into early Sunday morning.

- Drier with near average high temperatures (upper 70s to low 80s) are expected Sunday and Monday.

- Rain showers and thunderstorm potential increases again Monday night into Wednesday with chances for rain up to 50-80 percent.

DISCUSSION

Issued at 104 PM CDT Sat Aug 15 2026

Rest of Today: Storm Chances This Evening

Persistent cloud cover is forecast for the rest of today as low to mid level moisture continues to round the top of the H300 ridge of high pressure. As a result of the cloud cover, highs for this afternoon should be in the upper 70s to low 80s, so overall it will be a very nice day even though the sun will not be out very much for most areas. A shortwave trough, which is currently located over Nebraska into South Dakota, will continue to move northeast and east this afternoon into this evening. As the shortwave approaches the Upper Mississippi River Valley, a weak surface front should be moving east across Minnesota into Wisconsin this evening. These features combined with sufficient moisture throughout the column, should lead to at least isolated to scattered showers and storms later on today. Even though there are some chances (10-20 percent) for a few pop-up showers this afternoon, the better chances for any rain will be as the front moves over the region this evening. Severe thunderstorms are not expected at this time. Even though moderate to heavy rain will be possible with the strongest cores, given PWAT values approaching 2 inches and long skinny CAPE profiles depicted by forecast soundings, the potential for flooding is low since the storms should be moving fairly quickly. Any showers or storms that do develop should dissipate or move off to the east very early Sunday morning.

Sunday and Monday: Mild Temperatures and Drier Conditions

High pressure across the southeast should decrease in strength on Sunday into Monday and westerly flow is expected to prevail over the region on both of these days. In the wake of the weak frontal passage on Saturday night into Sunday morning, drier air should settle in over the area leading to dry conditions. Mostly clear skies on both of these days along with H850 temperatures in the mid teens Celsius should lead to seasonal temperatures to end the weekend and begin the next work week. The dry conditions will not last long however, as moisture returns to the region on Monday evening. Lift provided by a fast moving shortwave may bring rain showers and storms to the area going into Tuesday morning.

Rest of Next Week: Trending Cooler with More Chances for Rain

Westerly to northwesterly upper level flow is forecast for the middle to later half of next week as troughing develops over eastern Canada into the northeastern CONUS. This trough will usher in a cooler air mass over the Upper Mississippi River Valley and cooler temperatures in the 70s are expected through the next week. High pressure is expected to remain mainly suppressed to the Desert Southwest most of next week before potentially building back north towards the Pacific Northwest by Friday. The best chance for rain next week looks to be Tuesday night into Wednesday at this time. The latest 15/13z NBM has up to a 30-40 percent chance to reach or exceed 1 inch of rain across the far southern portions of the CWA during this time frame with higher chances (50-60 percent) across central Iowa. The area of the potential heaviest rainfall has trended further south of the past 24 hours but given this is still 4 days out there remains uncertainty in exactly where the best chances for rain will fall. Given mainly westerly flow aloft, shortwaves embedded in this flow may lead to additional chances for showers and storms beyond Tuesday, but timing differences leads to low confidence at this time.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 629 PM CDT Sat Aug 15 2026

A cold front will provide a chance of showers and storms as it moves east through the area this evening and the early overnight. If there are any storms, they would occur between 16.02z and 16.06z at KRST and from 16.03z and 16.07z at KLSE. Ceilings will be mainly IFR/MVFR through mid-morning and then they will become VFR.

ARX WATCHES/WARNINGS/ADVISORIES

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