textproduct: Milwaukee/Sullivan

KEY MESSAGES

- A clipper system brings higher-end shower chances (50 to 80 percent) for Tuesday morning. A passing cold front Tuesday afternoon may bring a few thunderstorms. Gusty winds and small hail may occur with the strongest storms, if they develop.

- A brief period of gales is possible over the middle third of the open waters of Lake Michigan late Tuesday morning into Tuesday afternoon.

- A cool and cloudy day is expected for Wednesday.

- Relatively warm and humid conditions with increasing storm chances returns from Thursday night into the weekend.

SHORT TERM

Issued 1106 PM CDT Mon May 11 2026

Today through Wednesday night:

Low pressure will approach from the northeast tonight, dragging a warm front over southern WI around daybreak. WAA on the leading edge of the warm advection will drive showers around dawn and through the morning hours. All of these showers will be elevated with negligible MUCAPE, so thunder is not expected. Shower activity will then grow more scattered heading into the afternoon as the main push of mid level WAA moves east/northeast, with strong surface WAA on gusty southwest winds advecting a warm surface airmass in the mid 70s into southern WI. A cold front is then expected to move through the area during the mid to late afternoon. Shower and storm coverage and strength along the front will be highly contingent upon air mass recovery during the late morning into the mid afternoon. At this time, CAMs depict just enough instability along the front (~400 J/kg CAPE) to drive scattered storm development. However, the skinny nature of the modeled CAPE profiles will limit storm strength and severity. A few rumbles of thunder are most likely with activity along the front, while small hail and gusty winds will remain isolated and only occur with storms that manage to become well established in Far SE WI before moving over Lake Michigan.

Following the cold front, sfc CAA will usher in a cooler air mass for Wednesday. Highs will be in the low to mid 60s amid breezy northwest winds. Light frost may occur Wednesday night into Thursday.

CMiller

LONG TERM

Issued 1144 PM CDT Mon May 11 2026

Thursday through Tuesday:

A gradual warming trend will take hold on Thursday as upper level ridging from the Plains leans east into the Great Lakes region. Highs are projected to rise into the 80s on Saturday. The warming will be spurred on by multiple waves of WAA, most notably Thursday night into Friday, then Saturday into Sunday. With these waves of WAA, expected shower and storm chances and modest increases in humidity. Beyond, models vary a bit regarding how showers and storms will evolve along a passing cold front on Sunday and how much rain will linger into Monday, with the ECMWF favoring a drier solution, while the GFS favors storms Sunday night and lingering showers Monday. In either case, warmth sticks around for the end of the extended period.

CMiller

AVIATION

Issued 1104 PM CDT Mon May 11 2026

Expect continuing VFR overnight with light to moderate southeast winds. Winds are expected to increase from west to east around dawn tomorrow and become gusty between 25 to 30 knots, with some potential gusts to 35 knots for KFLD and KSBM.

Rain is also expected to move in around daybreak, though ceilings will remain VFR. More redevelopment may occur over southeast Wisconsin in a line from KSBM to KJVL late in the afternoon. This development will feature better thunder chances and some of the strongest storms may have gusty winds and small hail, though widespread severe weather is not expected.

CMiller

MARINE

Issued 1051 AM CDT Mon May 11 2026

High pressure will continue to shift east tonight. Light and variable winds will become south-southeasterly by dawn Tuesday, with gusty winds developing over the lake quickly through the morning hours as low pressure approaches from the northwest. Forecast models suggest that despite a near surface temperature inversion over the lake, showers over the lake will mix down gales from the late morning through the mid afternoon. A Gale Warning has been issued for this time period, over roughly the middle third of the lake. Gusty winds then ease a bit during the early evening hours as a cold front passes and winds become northwesterly. Gusty northwest winds then return Wednesday morning in the cold advection regime behind the cold front.

North to northwest winds then ease Wednesday night into Thursday as high pressure moves over Lake Michigan.

Locally, a Small Craft Advisory is in effect Tuesday morning into Wednesday afternoon for lingering southerly and then northwesterly gusty winds. A few gale force gusts can't be ruled out north of Port Washington Tuesday late morning into the mid afternoon.

CMiller

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Gale Warning...LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-LMZ669- LMZ671-LMZ868-LMZ870-LMZ872...9 AM Tuesday to 5 PM Tuesday.

Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...9 AM Tuesday to 4 PM Wednesday.