textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Showers (60-90 percent chance) and scattered thunderstorms on Tuesday. Small hail expected with the thunderstorms.

- Widespread showers (80-90 percent chance) and scattered thunderstorms Wednesday and Wednesday night. Heavy rain and a conditional threat for severe thunderstorms is forecast.

- Next chances for thunderstorms develop Saturday and Sunday.

UPDATE

Issued 601 AM CDT Mon Jun 15 2026

High clouds across the eastern half of the forecast area early this morning will continue to depart to the east, leaving mostly clear skies across southern Wisconsin through at least mid-morning. Mid to high level clouds will then push in from the northwest by the afternoon hours ahead of an approaching shortwave. In all, the forecast looks on track through the upcoming day, with high temperatures warming back into the mid 70s.

DDV

SHORT TERM

Issued 1037 PM CDT Sun Jun 14 2026

Tonight through Wednesday night:

Scattered cirrus clouds are expected to move across srn WI during the overnight as the shortwave trough over ern SD and NE tracks to north central IL by 12Z Mon. At the surface, calm winds will become lgt wswly as a weak sfc ridge shifts south and a west to east sfc trough moves swd across nrn Ontario. Good radiational cooling conditions in an already cool airmass will support low temps in the upper 40s inland from the lake.

The next upstream shortwave trough will track into the ern Dakotas on Mon, then amplify as it moves to se MN by 12Z Tue. The west to east sfc trough over Ontario will move to nw WI and Lake Superior during this time. Partly cloudy skies and weak warm advection on Mon should boost temps into the middle 70s. By late Mon nt, a swly low level jet around 35 kt and associated warm, moist advection will develop into srn WI ahead of the amplifying upper wave. Rain chances will increase to 20-40 percent, including chances for thunderstorms as the Showalter Index falls to -1C. More widespread showers and scattered thunderstorms will then develop on Tue as the low level jet and warm, moist advection overspreads the area and is quickly followed by the shortwave trough and cold frontal passage. The 998 mb sfc low will be tracking from nw WI to nrn Lake MI during this time. There is uncertainty with the timing of the cold front of late morning into the early afternoon versus just an afternoon passage. Either way believe showers and clouds will keep temps down a bit, although tall, skinny CAPE of 500-1000 J/KG could be achieved. Given low freezing levels around 8 kft, any thunderstorms would likely have small hail with just very low probabilities for large hail at this time. A few showers will linger into Tue evening and briefly be followed by a weak ridge of high pressure.

A positive tilt shortwave trough will then move across the nrn Great Plains to srn WI Wed-Wed nt, with the sfc low to track anywhere from central WI to nrn IL. A strong low to mid level baroclinic zone will set up over srn WI with warm, moist advection and frontogenesis producing widespread showers and storms. PWATs will climb to 1.5 inches toward the IL border. Elevated severe storms and heavy rainfall will be possible.

Gehring

LONG TERM

Issued 1037 PM CDT Sun Jun 14 2026

Thursday through Sunday:

Cold advection will prevail on Thursday in the wake of low pressure. Another shortwave trough will pass and maintain 20-30 percent chances for showers. Weak shortwave troughs will then continue to bring small chances for showers and possibly storms, more so for the weekend. Temps will remain a bit on the cool side.

Gehring

AVIATION

Issued 601 AM CDT Mon Jun 15 2026

Quiet weather is expected through at least the evening today, with periods of mid to high level clouds moving through ahead of an approaching trough. There will be a chance for showers the second half of tonight into Tuesday morning, with a chance for thunderstorms as well by Tue afternoon. Light westerly winds this morning will pick up a little for the afternoon hours, becoming southwest tonight into Tuesday as the trough continues to approach.

DDV

MARINE

Issued 1037 PM CDT Sun Jun 14 2026

Northwest winds will gradually diminish this evening, becoming west to southwesterly over all of the lake late tonight, as a weak wave of low pressure moves south across Ontario and high pressure extends across the central portion of the country. Low pressure is then expected to deepen to 29.5 inches over northern Wisconsin on Tuesday, then move across northern Lake Michigan into the early evening. This will bring breezy southerly winds to the lake on Tuesday shifting west to northwest after the low passes. Numerous showers and scattered thunderstorms are forecast over central and southern Lake Michigan on Tuesday.

On Wednesday, low pressure around area 29.2 inches will move into the Upper Mississippi River Valley from the Great Plains. This will bring breezy southeasterly winds to central and southern Lake Michigan Wednesday afternoon and evening, with the low to then move across central Lake Michigan Wednesday night. As low exits into Thursday morning, expect winds to become northwesterly and remain gusty across all open waters into Thursday afternoon, before gradually diminishing. Widespread rain and scattered thunderstorms are forecast Wednesday and Wednesday night.

Gehring

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...None.