textproduct: La Crosse

KEY MESSAGES

- Potentially dangerous heat will persist through Tuesday (possibly longer). As a result, there was no changes made to either the Heat Advisory in Clark County (WI) and the Extreme Heat Warning for the remainder of our forecast area.

- There will be periodic showers and storms this week. Some of these storms could be strong to severe. Like the past couple of days, the timing remains uncertain.

DISCUSSION

Issued at 1234 AM CDT Mon Jun 29 2026

Main and highest confidence forecast impact continues to be extreme heat across the Upper Midwest for much of the week. While highest daily confidence for highest temperatures continues to be Monday and Tuesday across the Upper Mississippi River Valley in long term global ensembles and NBM solutions, a meager intermodel dProg/dT cool down in 850mb temperatures has throttled previously warmest LREF member solutions (GEPS/EPS) 2-4 degrees at the surface, resulting in confidence for lower 90 high temperatures today. Regardless, mid-70 degree isodrosotherm through the forecast area results in heat indices surpassing Extreme Heat Warning criteria both days, and therefore have continued with previously issued Extreme Heat Warning across the forecast area outside of Taylor County with the Heat Advisory.

Lower, albeit inherently both causal and effectual with the extreme heat, confidence forecast impacts will be storm potential initially Monday night. Current confidence in location of higher pressure and resultant excited low level return flow initializes linear storms west of the forecast area through south-central into western Minnesota Monday evening. As storms progress east-southeast within the mean southwesterly flow expected an overall weakening trend due to interaction with the anomalous ridge as they approach the forecast area. Therefore, while current PoPs remain limited, primarily grazing the western-northwestern peripheral counties from southeast Minnesota with <20%, should more excited storms be able to penetrate farther east or the high be slightly shifted east, PoPs will require an increase.

While current forecast increases PoPs for Tuesday night bifuricating the northwestern half of the forecast area, similar dependence on frontal boundary's eastern extent Monday night will impact storm location. Meager open perturbations attempt to budge the ridge east as the upper level extratropical cyclone deepens and slightly shifts east-northeast towards southern Canada, persisting periodic storm threat locally.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 605 AM CDT Mon Jun 29 2026

As a warm front continues to move northeast of the area this morning, there will be IFR/MVFR ceilings primarily along and north of Interstate 94. These lower ceilings should move north of Taylor County (WI) by early this afternoon.

A line of storms may or may not move into the area during the late evening and overnight. Confidence was not high enough to include them in the TAFs at this time.

CLIMATE

Issued at 1234 AM CDT Mon Jun 29 2026

With 850 mb temperatures 2 to 2.5 standard deviations warmer than normal, there will be a potential for some warm low temperature records to be tied or broken south of Interstate 94 from today into Wednesday.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Extreme Heat Warning until 9 PM CDT Tuesday for WIZ029-032>034- 041>044-053>055-061. Heat Advisory until 9 PM CDT Tuesday for WIZ017. MN...Extreme Heat Warning until 9 PM CDT Tuesday for MNZ079-086>088- 094>096. IA...Extreme Heat Warning until 9 PM CDT Tuesday for IAZ008>011-018- 019-029-030.