textproduct: La Crosse

KEY MESSAGES

- Potentially hazardous heat continues through at least Wednesday.

- Canadian and northern Minnesotan wildfire smoke will likely move over much of the area tomorrow.

- Daily thunderstorm potential (20-40%) during the afternoon and evening hours returns starting Thursday.

DISCUSSION

Issued at 1231 PM CDT Tue Jul 14 2026

Potentially hazardous heat continues through Wednesday

Upper ridge centered roughly over the CWA early this afternoon will continue to lead to afternoon temperatures in the mid 90s through at least Wednesday. This, combined with dewpoints around 70, will yield heat index values near 100. While values have yet to actually reach Heat Advisory criteria within our CWA, pattern across ensembles continues to show members solidly on the high side of climatology but without extreme outliers. Given the lack of actually hitting even Advisory criteria, will not upgrade to an Extreme Heat Warning. But, given the long period of near Advisory level heat, have maintained the Heat Advisory.

Smoke likely arrives in some form tomorrow

A turn toward northerly winds at 925/850mb looks to advect smoke from the fires near the boundary waters to much of Wisconsin and eastern Minnesota. While this may bring very slight relief to temperatures, outdoor hazard from reduced air quality is possible as 14.06z HRRR output depicts some of this smoke settling in at the surface. Relatively stagnant air mass suggests that, should smoke settle in, it may stick around through Friday.

Diurnal thunderstorm potential returns Thursday

As the upper ridge bringing the ongoing heat moves to our southeast, northwesterly flow aloft sets up over the region. As disturbances eject southeastward, they may (20-40%) kick of rounds of showers and thunderstorms, particularly during the afternoon and evening. Given continued warm and humid conditions, at least 1000 J/kg of CAPE appears pretty likely (70-90% per 14.00z LREF) each afternoon/evening but shear remains a limiting factor. Reflecting this, both GEFS and ECENS ML output have a broad but small (5%) chance for a severe storm Thursday through Monday afternoon/evening. At this time, based on the pattern, would lean toward Saturday having just a bit more risk given potential for a relatively weak (60 kt) upper jet to advance over the CWA. In any case, those with outdoor plans will need to remain alert this weekend.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 619 PM CDT Tue Jul 14 2026

Valley fog looks to be a possibility tonight. Due to this, kept the BCFG at the KLSE TAF between 15.10z and 15.14z. Otherwise, VFR conditions are expected through 15.24z.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Heat Advisory until 8 PM CDT Wednesday for WIZ029-032>034- 041>044-053>055-061. Heat Advisory until 9 PM CDT this evening for WIZ017. MN...Heat Advisory until 8 PM CDT Wednesday for MNZ079-086>088- 094>096. IA...Heat Advisory until 8 PM CDT Wednesday for IAZ010-011-030.