textproduct: La Crosse

KEY MESSAGES

- Thunderstorm chances return this weekend into early next week with the potential for severe storms on Sunday and perhaps again on Monday.

- Heat index values of 100 or higher on Sunday and Monday could lead to heat related illnesses and a Heat Advisory may be needed for parts of the area on both of those days.

DISCUSSION

Issued at 401 AM CDT Fri Jul 24 2026

This Weekend into Next Week: Storm Chances Return

Upper level ridging will become more pronounced this weekend as high pressure strengthens over the southern Rockies. Before the ridge has a stronger influence over the Upper Midwest, another very nice day is expected for today with highs once again in the 70s to low 80s. With northwesterly flow aloft, some elevated smoke from wildfires is expected to move over the area starting tonight and could last into the day on Saturday. Impacts from the smoke at the surface are not expected as the wind should remain out of the south to southwest. Rain showers or thunderstorms are not expected during the day, but a shower or storm may approach Taylor/Clark counties late tonight into Saturday morning.

Height rises will occur on Saturday into Sunday and strong WAA will occur in the low levels this weekend. Moisture throughout the column will be on the increase this weekend which should result in off and on chances for showers and thunderstorms, with the highest chances on Sunday afternoon into the evening. The potential is still there for strong to severe storms across portions of the area on Sunday, with the best potential across Wisconsin at this time. The axis for where the potential for severe storms will likely change some since we are still three days out and will be highly dependent on how far northeast the low level thermal ridge progresses. For areas that are more underneath the thermal ridge, a capping inversion around H800 should lead to much lesser threat for severe storms whereas areas further northeast will have less capping. For the areas in the more uncapped environment, sufficient instability and shear should be in place for some storms to become severe. The primary hazard seems to be damaging wind gusts, but large hail and to a lesser extent a tornado threat will also be possible. Thunderstorms may continue into the morning on Monday but the severe storm threat should decrease overnight.

Sunday and Monday: Summer Heat Return

Hot conditions are still likely to occur on Sunday and Monday as the aforementioned ridge influences the weather pattern across the central CONUS. H850 temperatures should be able to reach the mid 20s Celsius on both of these days. The increase in surface moisture with forecast dew points in the upper 60s to mid 70s will result in heat index values up to 10 degrees warmer than the air temperature. Confidence continues to increase in the potential for heat index values to reach or exceed 100 degrees on both Sunday and Monday. There is still some uncertainty in extent of hottest temperatures as cloud cover combined with convection could lead to temperatures being a few degrees cooler than currently anticipated. Have issued an Extreme Heat Watch where highest dewpoint temperatures keep confidence for reaching Extreme Heat Warning at least 50% for parts of southeast Minnesota and northeast Iowa. Will require additional fine tuning as forecast hour nears as well as Heat Advisory to the northeast is likely.

Troughing may become more pronounced over the Great Lakes region during the middle of next week which should weaken the ridge and push it a back further to the west. Warm summer time conditions are still expected the rest of the week even though the ridge may not have as much of an influence over the Upper Mississippi River Valley.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 635 AM CDT Fri Jul 24 2026

Predominantly VFR conditions through the TAF period. CIGS stay around 5kft to 10kft through the day then gradually lower this evening and overnight. MVFR CIGS move in early Saturday morning and are expected to linger through mid-morning. Southwest winds stay in the 5 to 15 mph range.

ARX WATCHES/WARNINGS/ADVISORIES

WI...None. MN...Extreme Heat Watch from Sunday afternoon through Sunday evening for MNZ094. IA...Extreme Heat Watch from Sunday afternoon through Sunday evening for IAZ008-009. Extreme Heat Watch from Sunday afternoon through Monday evening for IAZ010-018-019-029-030.