textproduct: Milwaukee/Sullivan

KEY MESSAGES

- A few showers and isolated thunderstorms will continue today.

- Multiple rounds of storms are expected Wednesday and Thursday. Severe thunderstorms are likely at times.

- Hot and humid conditions expected Wednesday and Thursday, with some potential for Heat Advisory conditions on Wednesday if we get enough sunshine.

UPDATE

Issued 542 AM CDT Tue Jun 9 2026

Areas of dense fog developed near the lakeshore of Sheboygan county and has expanded inland early this morning. The fog was apparent on lakeshore webcams, the webcams at Road America, and the WI DOT webcams. The Sheboygan airport reported one quarter mile visibility between 1 and 3 AM and now has an upward trend. The Dense Fog Advisory is in effect for only Sheboygan county until Noon, but it is likely we can cancel it early.

The storm potential is trending downward for today, but we can still expect isolated showers with a few rumbles of thunder for at least the morning hours.

Cronce

SHORT TERM

Issued 1238 AM CDT Tue Jun 9 2026

The rest of tonight through Tuesday:

Weak low pressure will gradually lift northeast through the forecast area tonight into Tuesday, with continued scattered showers and a few rumbles of thunder at times. The shower chances will wind down from southwest to northeast overnight into Tuesday, with the chances mainly east of Madison by Tue afternoon as the low begins to pull away from the area.

Mild temps are expected overnight tonight due to the moist airmass and persistent clouds. Bumped Tue high temps down a couple degrees from the previous forecast given the expected lingering clouds tomorrow.

DDV

LONG TERM

Issued 1238 AM CDT Tue Jun 9 2026

Tuesday night through Monday:

An area of moisture and warm air advection is expected to lift into the forecast area Tue night into early Wed. This may kick off a round of thunderstorms after midnight. Latest guidance is showing plenty of instability hanging on overnight along with modest 0-6 km shear around 30 knots. Additionally, mid-level lapse rates are expected to be upwards of 8-9 C/km Tue night into early Wed. If storms do develop overnight, confidence is increasing for a severe threat, with hail being the primary concern.

Storms should wind down by mid-morning Wednesday, with a break in activity likely late morning into the afternoon. This should be enough time for instability to build back up across southern Wisconsin, with another round of storms possible by early evening as a shortwave moves into the area. This second round of storms may develop just to the west of the forecast area, though initialization looks close enough for some possible discrete cells in at least the west before storms may eventually organize into a line. Shear is expected to be a bit stronger by evening, especially in the low levels. All hazards will be possible at first, likely transitioning to a wind and QLCS tornado threat as the storms progress eastward if they develop into a line. Still some time for the finer details of the severe storm concern to change given the complexity of storm timing, peak heating, effective boundaries, and so on. Overall though, confidence is increasing in this second round of potential severe storms for southern Wisconsin.

In between the two rounds of storms, there should be some breaks in the clouds, allowing temps to warm towards 90 degrees most places. Given dewpoints in at least the low 70s, heat indices may approach or hit 100 degrees, so this period is still being watched for a potential Heat Advisory.

Showers and storms Wed should exit the east by early Wed night, with dry weather likely overnight into early Thursday. The main shortwave and cold front are expected approach from the west during the day Thursday, with another round of storms possible as this better forcing moves through the area. Model instability points to the south half of the forecast area as having the best chance to see another round of storms, with a decent shot at another severe potential if convection rolls through the area. Deep layer shear is looking a bit stronger Thu than Wed, with ample instability and solid lapse rates as well. Warm and humid conditions are expected again Thursday, with the warmest conditions likely in the east.

Dry weather is expected Friday behind the departing low and front, with high temps back towards normal values. Dewpoints will be lower as well, likely settling into the 50s most places.

Saturday through Monday are trending a bit more active, with multiple shortwaves likely to move through the region during this period. There is a lot of spread with the timing and placement of individual waves along with the depth of the moisture, amount of instability, etc. Kept precip chances on the lower end for now given the lingering uncertainties.

DDV

AVIATION

Issued 542 AM CDT Tue Jun 9 2026

Ceilings at MVFR levels (IFR in a few spots) will gradually improve to VFR by late afternoon. Expect isolated showers with a slight chance of lightning, mainly through midday.

Dense fog developed along the shoreline of Sheboygan county and spread inland overnight. Expect the land-fog to diminish by mid morning. More widespread marine fog is expected late this afternoon through tonight, so lakeshore areas may be affected by some of it drifting inland (MKE, RAC, ENW, ETB, SBM) as the lake breeze develops.

Scattered storms are possible early Wednesday morning. Severe hail and winds would be the hazards. Additional rounds of storms, possibly severe, are expected Wednesday afternoon through Thursday.

Cronce

MARINE

Issued 542 AM CDT Tue Jun 9 2026

Light and variable winds will increase and become northerly by this evening as low pressure of 29.9 inches crosses the center part of Lake Michigan. Dense fog is expected at times through tonight due to a warm and humid airmass over the relatively cool waters. A Marine Dense Fog Advisory is in effect for central portions of the lake at this time. An advisory that covers more of the lake may be needed tonight. There is a chance of showers with a few rumbles of thunder through tonight as well.

Breezy southerly winds are expected Wednesday and Thursday as strong low pressure around 29.2 inches tracks from southern Saskatchewan to Hudson Bay. Multiple rounds of showers and storms are likely during this time, along with a chance for severe storms. West to southwest winds and dry weather are then expected Friday behind the departing low.

Cronce

MKX WATCHES/WARNINGS/ADVISORIES

WI...Dense Fog Advisory...WIZ052 until noon Tuesday.

LM...Dense Fog Advisory...LMZ366-LMZ565-LMZ567-LMZ643-LMZ669-LMZ868- LMZ870 until noon Tuesday.