textproduct: Milwaukee/Sullivan

KEY MESSAGES

- The Wisconsin DNR has extended the Air Quality Advisory for eastern Wisconsin that remains in effect until 6 PM CDT today. Any lingering wildfire smoke will lead to unhealthy air quality for sensitive individuals. - Severe storms are possible late this afternoon into this evening. All severe hazards are possible, with an Enhanced (level 3 out of 5) threat level. There is increasing likelihood for severe storms with uncertainty on exact placement.

- There is a High Swim Risk for area beaches in Ozaukee and Sheboygan County beaches this afternoon. Life threatening waves and currents are expected in High Swim Risk areas. Stay out of the water, and away from dangerous areas like piers, breakwalls and river outlets.

SHORT TERM

Issued 1200 PM CDT Mon Jul 20 2026

Late Afternoon through Tuesday night:

The current expectation is for the WAA induced convection to push out over the next hour or so allowing for a period of sun to bring recovery of the environment to the area, with the recovery northwest of the CWA already ongoing. This important due to west central WI likely being the the general initiation location for storms later this afternoon/early evening. A few models point toward some more isolated storm initiation mid to late afternoon but models have trended down on this likely due to the impact of the morning convection and the likelihood that there would not be enough recovery time behind the WAA related convection this morning. However, models have trended in the other direction for the convection potential into the evening.

While perhaps underselling the morning convection a tad, models have generally caught on to the true trend in the morning activity and thus we have been able to trust their output a bit more. The conditions set up for the front associated with the low pushing through the northern Great Lakes to be the initiator of convection from eastern IA up to the UP of MI. In addition, a strengthening LLJ into the evening will increase low level and deep layer shear with models indicating an enlarged hodograph with 200-300 m2/s2 0-3km SRH and 50-70kts of deep layer shear. While uncertainty exists in the afternoon recovery, it looks likely for NE IA, SE MN and west central WI, where initiation is expected to occur, to have had much of the day to recover with areas further southeast likely having reduced instability but plenty of instability nonetheless. In the area of initiation, dewpoint climbing to mid 70s with upwards of 5000 J/kg of SBCAPE is expected (4000 J/kg MLCAPE) with decreasing instability further southeast but still plenty.

All hazards with this event are possible including strong tornadoes, large hail and damaging winds. The way models portray this event unfolding is suggestive of widespread initiation but when that occurs usually there are just a few storms which generally take over while others gets suffocated by the stronger storms environment. If this plays out this way the area of concern will shrink but there would be significantly heightened concerns for those in the path of those stronger storms.

Storms will likely clear out of the area just after midnight with little to no weather concerns overnight as the front will have pushed through. High pressure will however hold back a bit into Tuesday as the low pressure system sticks around and may even bring a backdoor cold front during the day Tuesday which may yield some light showery activity. However by Tuesday night the high pressure will start to build in from the west with quieter conditions expected. However, the higher pressure may start to usher back in some smoke to southern WI.

Kuroski

LONG TERM

Issued 1200 PM CDT Mon Jul 20 2026

Wednesday through Monday:

High pressure will push over souther WI and northern IL for Wednesday and stick over the area through at least Thursday while gradually drifting east and gradually weakening through Friday. There is at least some potential for convection Friday and Saturday but this appears unlikely at this time given a bit more activity aloft. However, chances increase late weekend and early next week as lower pressure swings in. Uncertainty increases for this period but looks to be the best chance for precip and storms in the extended. Timing will determine any storm concerns for this but too early to tell at this time.

Kuroski

AVIATION

Issued 1200 PM CDT Mon Jul 20 2026

While smoke hangs around causing some patchy MVFR VSBYs our attention turns to this afternoon where we should expect a round of strong to severe storms which may end up being more isolated in nature than current models suggest but all hazards including large hail, tornadoes and damaging winds would be possible. The time frame for this is primarily between 6pm and Midnight where storms will track southeast across southern WI. After storms pass through the front with come through bringing winds to the northwest and breezy. North winds primarily Tuesday with another backdoor cold front potentially bringing showers during the afternoon. Otherwise expect higher pressure to build back in Tuesday night. Smoke concern with VSBYs restrictions may return as winds turn back north to northeast with the approaching high pressure.

Kuroski

MARINE

Issued 1200 PM CDT Mon Jul 20 2026

Wildfire smoke still encompasses parts of the lake but it is no longer dense and no longer significantly impacting visibilities and thus the Marine Dense Smoke Advisory is no longer in effect.

Low pressure tracking southeast through southern Ontario will drag a cold front across the lake tonight. South to southwest winds ahead of the front will become gusty. An occasional gale force gust will be possible this afternoon and evening over the northern half of the lake. Strong to severe thunderstorms will also be possible this afternoon through tonight across the entire lake. Winds will veer northwest behind the cold front and remain gusty. Then winds veer due north later Tuesday into Tuesday night with gusts to gale force possible. Heading into Wednesday winds are expected to diminish becoming light and variable by Wednesday night as high pressure builds into the Great Lakes Region.

Kuroski

MKX WATCHES/WARNINGS/ADVISORIES

WI...Beach Hazards Statement...WIZ052-WIZ060...1 PM Monday to 7 AM Tuesday.

LM...Small Craft Advisory...LMZ643-LMZ644...1 PM Monday to 7 AM Tuesday.

Small Craft Advisory...LMZ645...1 PM Monday to 1 AM Tuesday.