textproduct: La Crosse

KEY MESSAGES

- Maybe some small chances (less than 5 percent chance) of severe weather late this morning and early afternoon in Wisconsin.

- Temperatures gradually warming from Saturday through Monday.

- Maybe some severe weather Monday night into Tuesday morning

DISCUSSION

Issued at 1248 AM CDT Wed Jun 24 2026

Today

A shortwave trough will move east through the region this morning and early afternoon. As the overnight progresses, the shower and thunderstorm coverage will gradually wane. This will allow for some recovery in the instability (up to 1800 J/kg) from late morning into the afternoon. The greatest instability will be found in Wisconsin. As the 850 mb and 700 mb winds increase, the hodograph will increase in length. This might result in a few splitting supercells. The better chances of this occurring would be in central and eastern Wisconsin. With temperatures cooling aloft in the afternoon, hail would be the greatest severe weather threat, but even that threat looks to be very low (2-5%). There might be even a secondary threat for damaging wind gusts.

High temperatures will range from the lower 70s to lower 80s. The warmest temperatures will be in the Mississippi and Wisconsin river valleys.

Thursday and Friday

Zonal flow will develop across the eastern two-thirds of the CONUS on Thursday and then continue into Friday. A Canadian surface high over Lake Superior will keep a stationary front located from the Mid- Mississippi River Valley east into the Mid-Atlantic Region. A dry north to east flow will keep the rain chances well south of the forecast area. High temperatures will be in the lower and mid-70s on Thursday, and in the mid- to upper 70s on Friday.

Saturday through Monday

The models remain in good agreement that a longwave trough will gradually deepen from Saturday into Monday over the western CONUS. As this occurs, a 500 mb ridge will build northward from the western and central Gulf northward to Hudson Bay. On Sunday, a warm front will provide a chance of showers and storms as it moves east and northeast through the Upper Mississippi River Valley. High temperatures will gradually warm during this time period. They will range from the mid-70 to lower 80s on Saturday, in the 80s on Sunday, and range from the upper 80s to mid-90s on Monday. With dew points climbing into the lower and mid-70s, heat indices will likely range from the mid-90s to 105.

Monday night and Tuesday

A shortwave trough ejects out of the western ridge on Monday night. As this system moves through the Dakotas and northern and western Minnesota, the ridge gradually flattens. This will provide a chance of showers and storms. Initially the capping will be strong enough on Monday and much of the Monday evening. This will allow most- unstable CAPES to build into the 2-3K J/kg range. During the mid- to late afternoon, discrete supercell thunderstorms are expected to develop across the Dakotas and northern and western Minnesota. During the evening, the cold pools with these storms will likely coalesce and a line of storms will move into the region either during the late evening or the overnight. If severe weather occurs in our area, it would be likely in the form of damaging winds. High temperatures on Tuesday will likely be around 90. Heat indices will range from the mid-90s to around 100.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 544 AM CDT Wed Jun 24 2026

Area of TSRA is slowly exiting to the southeast and has cleared a CCY to ISW line as of issuance time. Attention briefly turns to the north where stratus is diving southeast over the Twin Cities. Current thinking is that winds out of the west to 10-15 mph should assert themselves soon after sunrise and help to keep this out of RST/LSE but will need to keep an eye on this over the next ~3 hours. Then, potential for additional SHRA and TSRA returns this afternoon, mainly east of the Mississippi. With LSE roughly on the western edge of higher probabilities, have continued with a PROB30 TS mention with this update. Interestingly, uncertainty focuses around possibility (20%) for an early thunderstorm before 18z so may need to adjust ongoing timing with an amendment if necessary. In any case, TS potential should clear out of the area west to east a bit after 00Z with VFR conditions to follow until near 12z, when stratus may return to central WI.

ARX WATCHES/WARNINGS/ADVISORIES

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