textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Quiet and dry weather expected through tonight and Saturday morning.

- A few rounds of scattered thunderstorms expected Saturday midday through Saturday night. An isolated storm may become strong to severe, with damaging winds and hail the main threats.

- Below normal temperatures for early next week.

- Next chances for thunderstorms develop Tuesday and Wednesday next week. Too early to tell intensity, but monitoring for potential stronger storms, especially on Wednesday.

SHORT TERM

Issued 303 PM CDT Fri Jun 12 2026

Tonight through Saturday night:

High temperatures today in the upper 70s to low 80s within dry westerly flow. No precipitation is expected this afternoon. Winds will gradually diminish tonight, becoming southwesterly into Saturday.

As southwesterly flow becomes established over southern Wisconsin Saturday, expect temperatures to rise into the low to mid-80s, humidity to increase (dewpoints in the low 60s), and CAPE to increase to near 1200 J/kg. A weak frontal boundary will set up across northern to central Wisconsin during the afternoon hours, with isolated storms expected to develop in the pre-frontal region in central Wisconsin (currently looking to stretch as far southward as the I-94 corridor). Storms upstream in Iowa in the morning hours may progress eastward midday, but confidence is low at this time. Forcing is not expected to be strong during the afternoon hours, as the surface front is quite shallow and oriented west-to-east through the region of southwesterly flow. Still, if a few storms do develop (20-30% coverage), potential for a few to become strong to severe with gusty/damaging winds and hail still exists.

Going into the late afternoon/evening hours, the 500 mb trough begins to push southward, bringing additional lift to the region. CAMs still have quite a bit of timing discrepancies for precipitation development with this shortwave, with faster models showing development by 4 PM and slower models indicating an arrival time after 8 PM. Still, the primed environment and global modeling indicates enough potential to see a broken line of storms moving southward between 4 and 9 PM (50-70% chances). There is some indication that storms may linger across far southeastern Wisconsin into the late overnight hours, bringing potential for some local flooding across areas that saw substantial rainfall the past few days (15-20% chance of additional rainfall over 1 inch south of the I-94 corridor). Precipitation will exit completely by Sunday morning.

MH

LONG TERM

Issued 303 PM CDT Fri Jun 12 2026

Sunday through Friday:

Dry conditions with brisk northwest winds as high pressure builds into the High Plains on Sunday, with highs only nudging up into the upper 60s to low 70s. With plenty of sunshine, if winds diminish during the afternoon some locations may reach the mid-70s. Lows in the 50s expected overnight. High pressure slowly slides southeastward into the Lower Mississippi Valley on Monday, bringing southwesterly return flow to the Great Lakes region.

Meanwhile, a stronger shortwave rotating through the main flow around a deep trough over the Hudson Bay will begin to progress southward into the northern Plains. By Tuesday, expect developing low pressure in the northern Plains to begin to propagate eastward. This will bring the next chances for storms to southern Wisconsin within the frontal features of this developing low. At this time, southern Wisconsin looks to be within the warm sector, so stronger storms cannot be ruled out. However, intensity will be dependent on frontal timing as it will largely depend on how much instability can build across the region.

Low pressure swings back northeastward into the Hudson Bay Tuesday night into Wednesday, but an additional shortwave propagating southeastward from the Canadian High Plains will approach the Upper Midwest on Wednesday. This wave looks to tilt rapidly northward into Wednesday evening, bringing potential for additional rounds of strong storms to southern Wisconsin (PoPs 60-80%). Wrap around precipitation on the back side may continue to bring chances for rain and storms through Thursday (15-30% chances), before high pressure builds back into the Mississippi Valley on Friday.

MH

AVIATION

Issued 303 PM CDT Fri Jun 12 2026

VFR conditions through the remainder of today, with westerly winds gusting to 25 kt. Gusts up to 30 kt are possible for the next few hours near Lake Michigan. Winds will diminish tonight, becoming southwesterly and gusty again (20-25 kt) into Saturday morning. Saturday midday, a broken line of thunderstorms may progress eastward through the region (~15-30% chances). A better chance for widespread thunderstorms develops between 4 and 8 PM on Saturday, especially for MSN to MKE southward.

MH

MARINE

Issued 303 PM CDT Fri Jun 12 2026

Low pressure around 29.2 inches in the Hudson Bay will continue to bring gusty west-southwest winds to Lake Michigan through this evening. Conditions will remain hazardous for small craft in the nearshore regions of southern Wisconsin. Winds will gradually diminish this evening, increasing briefly again Saturday ahead of a cold front. As the cold front pushes north to south Saturday night, winds become northwesterly and brisk. Winds remain northwesterly but diminish through Sunday, remaining light and variable through Tuesday morning before low pressure develops in the northern Plains and brings gusty southwesterly winds to the lake through Wednesday. Winds become very gusty going into Wednesday evening as low pressure crosses the northern half of the Lake. A few gales are possible. Winds then shift to northwesterly as low pressure exits on Thursday.

MH

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 7 PM Friday.