textproduct: Milwaukee/Sullivan

KEY MESSAGES

- A High Swim Risk is in effect for Lake Michigan beaches in Racine and Kenosha counties this afternoon and evening, with a Moderate Swim Risk for Milwaukee county. Keep out of the water and away from dangerous areas like piers and breakwalls!

- Chances for thunderstorms late Tuesday night through Wednesday evening. A Marginal Risk for severe thunderstorms late Wed afternoon and evening.

- Slightly below normal temps continue through Friday with a strong warming trend early next week.

UPDATE

Issued 558 PM CDT Mon Jun 22 2026

High pressure is slowly building in from the Northern Plains and should be overhead of Wisconsin Tuesday. Diurnal cumulus clouds will remain across inland areas until sunset then they should dissipate. Fog will still be possible for areas north and west of Madison tonight. Under the clear skies, light winds and moist low levels it may be possible for some locally dense fog in low lying areas (ie: river valleys and marshes). Widespread dense fog is not currently expected. No major changes to the forecast.

Patterson

SHORT TERM

Issued 220 PM CDT Mon Jun 22 2026

Tonight through Thursday night:

A north to south sfc ridge will slowly move across srn WI tnt- Tue AM, reaching Lake MI in the afternoon. Low level instability will once again lead to sct-bkn cumulus clouds in the afternoon. For early Tue AM, areas fog, locally dense may form in the river valleys west of Madison.

For Tue nt, a well organized shortwave trough will track into nrn MN and wrn Lake Superior from Canada with its sfc low moving into nw WI. The warm front and associated swly low level jet of 25 kt will focus over srn and central WI. Fairly widespread showers (60-80 percent) and isolated thunderstorms will reach along and west of a line from Mineral Point to Madison to Sheboygan by 12Z Wed. The warm, moist advection and associated showers and isolated storms are expected to continue ewd on Wed. The weak sfc low around 1010 mb may track as far south as central WI then ewd across the lake Wed nt. A weak cold front will pass Wed nt but the wind fields and sfc convergence remains weak. Only isolated to scattered showers and storms are expected to develop later in the afternoon and evening after the warm frontal precipitation has exited. However, strong deep layer shear of 45-50 kt is expected in conjunction with MLCAPE of 1000-1500 J/KG. Thus there is a Marginal Risk for a severe storm or two. On Thu, the main upper wave will finally exit the nrn Great Lakes with 500 mb height rises over the region. The srn portion of a sfc ridge will build into srn WI late in the day and Thu nt. Another pleasant day in the 70s is forecast.

Gehring

LONG TERM

Issued 220 PM CDT Mon Jun 22 2026

Friday through Monday:

A shortwave trough will approach from the west during the day on Fri then move across WI and nrn IL Fri nt. There are 20-40 percent chances for showers and isolated storms with this upper wave. Afterward, high amplitude ridging is expected over the Great Lakes for the weekend into early next week. A gradual warm frontal passage will bring 30-50 percent chances for showers and storms with some uncertainty in the timing of the front. Eventually, hot and humid conditions will take hold some time early next week but with continued chances for showers and storms, as srn WI may be on the west side of the ridge axis and in the vicinity of an intermittent swly low level jet stream.

Gehring

AVIATION

Issued 558 PM CDT Mon Jun 22 2026

Largely VFR conditions are expected through the period. Diurnal cumulus clouds around 6 kft are expected to diminish/dissipate near sunset this evening. Then skies will be mostly clear through the rest of the night. For areas north and west of MSN (Madison), there will be a chance for fog to develop tonight into Tuesday morning. Fog could become dense in river valleys, widespread dense fog is not expected. MVFR to IFR visibilities will be possible for terminals in these areas (1-3 SM). For any terminals in the Wisconsin or Baraboo River Valley, visibilities could drop down to a 1/2 mile. Any fog that develop should burn off short after sunrise. Diurnal cumulus is expected to develop again Tuesday afternoon around 4-6kft.

North to northeast winds this evening will diminish tonight becoming light and variable. The light and variable winds are expected through Tuesday afternoon. With the light winds, a lake breeze is expected to push inland and switch winds to easterly. By Tuesday night, south to southwest winds will set up across the state.

Patterson

MARINE

Issued 220 PM CDT Mon Jun 22 2026

Modest northerly winds over the southern portion of the lake will gradually become light tonight as high pressure approaches. A surface ridge of 30.2 inches will then slowly move across Lake Michigan for Tuesday afternoon and evening with light and variable winds expected. By Wednesday, the high pressure will exit to the southeast and low pressure around 29.9 inches will track from northwest WI to across northern or central Lake Michigan Wednesday night. As the low approaches, modest southerly winds will develop on Wednesday, then shift west to northwest late Wednesday night and Thursday after the low passes. The winds will remain light the remainder of the week. A Small Craft Advisory continues until 9 PM CDT south of North Point Lighthouse due to 3 to 5 foot waves.

Gehring

MKX WATCHES/WARNINGS/ADVISORIES

WI...Beach Hazards Statement...WIZ071-WIZ072 until 9 PM Monday.

LM...Small Craft Advisory...LMZ645-LMZ646 until 9 PM Monday.