textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Patchy frost tonight

- Dry again Thursday with milder temperatures

- Warm and humid conditions with increasing storm chances late this week into early next week

SHORT TERM

Issued 1218 PM CDT Wed May 13 2026

This afternoon through Thursday:

Clouds will clear out later this afternoon into the evening as high pressure continues to build in from the west. The high will move overhead tonight, bringing light winds and mostly clear skies. Given the dry airmass in place, temps may fall enough for some patchy frost in the east tonight into early Thursday morning.

Light southerly winds will develop on Thursday as the high moves east of the area. Mostly sunny skies are expected tomorrow outside of isolated to scattered afternoon cumulus. Milder temps will return, with highs near 70 away from Lake Michigan. Winds will be onshore much of the day near the lake, resulting in cooler conditions.

DDV

LONG TERM

Issued 1218 PM CDT Wed May 13 2026

Thursday night through Wednesday:

There will be a chance for showers Thursday evening into early Friday morning as moisture and warm air advection aloft increase with the passage of a shortwave. Capped precip chances at 50 percent for now given a lot of dry air below 10 kft in model soundings.

It should be mainly dry and warm on Friday behind the departing wave. Plenty of sunshine by the afternoon in combination with breezy southerly winds should result in high temps in the upper 70s to low 80s most places.

The gradient of deeper moisture and higher instability is expected to be across southern Wisconsin or just south of the WI/IL state line Friday night. This may open the door for upstream convection Friday afternoon/evening to roll through the forecast area Fri night into early Sat. Still some uncertainty a couple days out with where the exactly the storms will form and where the moisture/instability will set up overnight, so only have 30-50% precip chances for now.

Saturday was looking dry, but latest models now have some deeper moisture and instability lingering across at least the southern forecast area during the day, keeping the door open for showers/storms given sufficient forcing from a weak wave, etc. The moisture and instability make a more definite return on Sunday per 12Z guidance, with increasing shower/storm chances later in the weekend as a result. Above normal temps will persist through the weekend.

Monday continues to look like the most likely period for widespread showers and storms, with southern Wisconsin solidly in the warm sector of an approaching low. Though a strong to severe storm isn't out of the question at times Friday night through Sunday, the overall setup for a few strong to severe storms currently looks best on Monday. Shear isn't currently expected to be particularly strong, but moisture, instability, and forcing look solid. Plenty of time for models to waffle on this setup though given it's still a few days out.

Confidence is on the lower end with precip chances for the Tuesday and Wednesday forecast given model timing differences with the exit of the early week system and the arrival of a mid- week low. Temps look cooler, with highs likely back near normal for Tue/Wed.

DDV

AVIATION

Issued 1218 PM CDT Wed May 13 2026

Scattered to broken VFR cumulus this afternoon should decrease in coverage late afternoon into the evening as daytime heating is lost and high pressure approaches from the west. Light winds and mostly clear skies are then expected tonight into Thursday morning. Southerly winds will pick up a little by the afternoon hours tomorrow, with winds more southeast to east near the lake due to a lake breeze developing by late morning. Few to scattered VFR cumulus will be possible in the afternoon away from the lake, but otherwise skies will remain mostly clear.

DDV

MARINE

Issued 1218 PM CDT Wed May 13 2026

Gusty northwest winds will continue this afternoon, as low pressure around 29.6 inches over southeast Ontario moves east of the region. A few gale force gusts may occur, particularly across northern and eastern portions of the lake. Lighter winds are then expected tonight into Thursday, as high pressure around 30.1 inches moves eastward through the region. Breezy southerly winds are expected to develop Friday, with a few gales possible Friday afternoon and evening in northern portions of the lake. South to southwest winds then linger Friday night into Saturday. Winds should then increase gradually for Sunday, as a warm front moves northward into the region, ahead of low pressure around 29.2 inches in the central Plains.

DDV

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 4 PM Wednesday.