textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Frost Advisory in effect for early Monday morning for all of S WI with the exception of Milwaukee, Racine, and Kenosha Counties.

- A clipper system brings higher end shower chances (60 to 90 percent) for Tuesday. A few thunderstorms will be possible, but no severe storms are anticipated at this time.

UPDATE

Issued 658 PM CDT Sun May 10 2026

Forecast details remain on track early this evening. A Frost Advisory remains in effect for most of southern WI tonight.

CMiller

SHORT TERM

Issued 201 PM CDT Sun May 10 2026

This afternoon through Monday:

High based stratocumulus once again this afternoon via low RH and cold air aloft. A stream of vorticity maximums extending back into se Manitoba will continue to traverse across srn WI into tnt. The cloud cover may hang on a bit over se WI due to the PVA. At the surface, ridging will expand from nrn MN across the nrn Great Lakes, which will initiate a weak backdoor cold front passage this evening into the overnight. Finally by 12Z Mon, the sfc high will be situated from Lake Superior through the nrn half of WI. Nely sfc flow should keep far se WI a bit milder than this morning, but otherwise low temps will likely range in the lower to middle 30s elsewhere. A Frost Advisory has been issued for all of srn WI with the exception of Milwaukee, Racine, and Kenosha Counties.

High pressure will then settle over Lake MI from the late morning into the afternoon with light and variable winds becoming esely winds. Less cumulus or stratocumulus clouds are expected on Mon, while high temps will range from the upper 40s at the Lake MI shoreline to the lower 60s over south central WI.

Gehring

LONG TERM

Issued 201 PM CDT Sun May 10 2026

Monday night through Sunday:

Models continue to support a fairly strong shortwave trough across nrn MN and the nrn Great Lakes Mon nt-Tue. The NAM and ECMWF continue to want to develop a wave of low pressure that tracks across central WI during this time. Despite some models lacking in QPF over far srn WI, still expect a well organized swly low level jet of 45-50 kt and warm, moist advection pattern to bring sufficient moisture and lift for widespread showers and perhaps scattered elevated convection. Small chances for sfc based convection along a weak wind shift or cold frontal passage remains for mid to late Tue afternoon. Only very marginal CAPE is expected given the high dewpoint bias of the NAM and GFS.

A shortwave trough in nwly flow aloft will then follow for Tue evening, while a stronger upper wave digs from the Lake Superior region across the nrn half of Lake MI. Although these features may not produce any precipitation, cold advection and some low level moisture may lead to widespread stratus clouds going into Wed.

High pressure will then follow for Wed nt-Thu followed by a jet stream pattern change to quasi-zonal for late next week and weekend. Various shortwave troughs will be tracking through the nrn and central Great Plains toward the wrn Great Lakes, bringing a return of warm and humid conditions and increasing rain chances.

Gehring

AVIATION

Issued 700 PM CDT Sun May 10 2026

VFR conditions will remain tonight through tomorrow. Expect dry conditions save for a few scattered sprinkles this evening.

Light northwest winds will become northeasterly tonight, and then light and variable tomorrow morning as the center of a high pressure system moves nearby. With the weak pressure gradient present tomorrow, a lake breeze will likely start pushing inland starting at 15z and continuing into Monday evening.

CMiller

MARINE

Issued 201 PM CDT Sun May 10 2026

High pressure around 30.3 inches is expected to move from southern Manitoba to over Lake Michigan by late Monday morning. Relatively light and variable winds are expected through Monday night. Low pressure around 29.7 inches should then move gradually east southeast across or north of Lake Superior Tuesday into Tuesday night. The low will bring a cold front southeast through the region. Gusty south to southeast winds are expected ahead of the front Tuesday, veering west to northwest behind it and remaining gusty for Tuesday night into Wednesday.

High pressure around 30.2 inches should then move southeast into the region Wednesday night into Thursday, bringing lighter winds.

A Small Craft Advisory will likely be needed from Sheboygan to Winthrop Harbor for Tue into Tue evening.

Gehring

MKX WATCHES/WARNINGS/ADVISORIES

WI...Frost Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057- WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ067- WIZ068-WIZ069-WIZ070...midnight Monday to 8 AM Monday.

LM...None.