textproduct: La Crosse

KEY MESSAGES

- Building heat through Tuesday with highs pushing into the upper 80s to mid 90s and heat indices ranging from mid 90s to around 100. These are expected to linger into Wednesday along and south of I-94.

- Heat gradually wanes after Wednesday and beyond with small shower/storm chances (20-30%) returning Friday into the weekend.

DISCUSSION

Issued at 120 PM CDT Mon Jul 13 2026

Hot conditions ahead

Upper ridge currently centered over central MN will slowly move southward over the next 5 days and reduce in magnitude as it does so, particularly after Wednesday. Strong agreement that this anomalous (climatological maximum heights across EC/GFS/CMC ensembles) will continue in the region through Wednesday with this also reflected in low (under 5F) interquartile spread for highs each day in the 13.13z NBM. While not comfortable by any means, this heat should be a bit less intense compared to a couple weeks ago as the air mass is drier, favoring top end heat index values around 100.

Given the continued signal for hot conditions with the ridge migrating overhead tomorrow, have expanded the Heat Advisory to cover more of SE MN, SW WI, and into NE WI and have extended this in time through Wednesday evening. On the other side of the spectrum, thinking high heights aloft will have waned enough in central WI by Wednesday afternoon that the Heat Advisory will not be needed in Clark/Taylor Counties, so have held their end time to Tuesday evening.

Potential for showers, storms returns Friday through Sunday

As the upper ridge reduces in magnitude and shifts to the south, northwest flow will resume over the CWA. While guidance disagrees on when precipitation potential will creep back into the area - the 13.00z GEFS suggests as early as Wednesday north of I-94 - should start to see a chance (20-40%) for showers and thunderstorms Friday through Sunday. Joint 13.00z LREF CAPE and shear probabilities suggest a low (20% or less) chance for organized convection without much support from ML-based guidance aside from some GEFS based output so, while continued monitoring will be needed, am not too concerned with severe thunderstorm potential at this time.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 629 PM CDT Mon Jul 13 2026

High pressure will continue to produce clear skies and generally light winds into Tuesday.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Heat Advisory from noon Tuesday to 8 PM CDT Wednesday for WIZ053>055-061. Heat Advisory until 8 PM CDT Wednesday for WIZ032>034-041>044. Heat Advisory until 9 PM CDT Tuesday for WIZ017-029. MN...Heat Advisory from noon Tuesday to 8 PM CDT Wednesday for MNZ086>088-094>096. Heat Advisory until 8 PM CDT Wednesday for MNZ079. IA...Heat Advisory from noon Tuesday to 8 PM CDT Wednesday for IAZ010-011-030.