Marine Weather and Tide Forecast for Milwaukee, WI

SHORT TERM
Issued 300 AM CDT Tue Jun 17 2025

Today and Tonight:

A cold front based from the low pressure system moving across the northern Great lakes will continue through the region early this morning but will for the most part remain dry outside of a few isolated showers. This front will layover and become stationary and east-west oriented as it becomes the warm front for the developing system over the Central Plains that will be push east toward the area today.

There still remains quite a bit of uncertainty on where this boundary will end up as it will be the focus for convection later today. In addition to the front there will some upper level support from a shortwave as well with some WAA to the low to midlevels on the nose of a weak LLJ. In addition moisture is not really expected to be an issue so this largely comes down to location of where things get going and models still show quite a bit of differences. Most of the CAMs show convection across at least parts of the area but the RRFS and HRRR keep most of the potential south of the area. We will need to closely monitor where the front sets up later today to determine where the best chances for storms will be. In either case while instability may be plentiful the deep layer shear will be weak and thus storms may not organize all that well. Depending on where the boundary sets up we could see upwards of 2000 J/kg of MUCAPE and thus we couldn't rule out stronger storms but that shear environment would not likely sustain them for very long. Large hail would be the primary concern with storms with a chance for stronger gusts as well, especially with any degree of organization.

Best chances for storms will be during the late afternoon through the mid evening hours with quieting conditions overnight ahead of the approaching low into Wednesday morning.

It is worth mentioning that temperatures will likely reach the mid 80s with temperatures possible reaching the 90s east of the Kettle Moraine in southeast WI with help from downsloping with west to southwest winds. In addition we could see dewpoints in some spots get near 70 making for some humid conditions. A lake breeze circulation may also form later in the day despite modest west winds as the temperature differences will be quite stark perhaps strengthening the circulation more than models currently project.

Kuroski

LONG TERM
Issued 300 AM CDT Tue Jun 17 2025

Wednesday through Monday:

Synopsis: Surface low pressure approaches from the central Great Plains and crosses our region on Wednesday, bringing additional chances for showers and thunderstorms, with a risk (level 1 or 2 out of 5)
for strong to severe storms and a marginal risk (level 1 out of 4)
for excessive rainfall. The strong / severe storm risk is conditional, and will depend on the exact track of the low pressure system, which is widely disputed among model guidance.

There is a chance for showers and thunderstorms to redevelop Thursday, wrapping around the back side of the departing low pressure. A deeper low pressure developing over the northern Plains will drag a warm front northward across the region on Friday yielding slight chances for showers and thunderstorms.
Behind the warm front, this weekend is looking very warm, with inland highs around 90 in the forecast and a modest southwest wind minimizing or even erasing the lake breeze.

Wednesday's Conditional Storm Threat / Analysis: The positioning and magnitude of CAPE varies widely from one ensemble member to the next, largely dependent on whether the low pressure system passes slightly north or slightly south of us. A track just south of the region (northern IL) would allow northeasterly winds off Lake Michigan to limit instability, whereas a central WI track would pull the warm sector deep into our region.

Ensemble and deterministic 500mb plots have a similar disagreement on upper-level dynamics and whether or not shear will be supportive of storm organization. A jet streak is expected east of a shortwave trough somewhere nearby, and it's proximity will dictate the amount of southwesterly deep shear we will receive.
Ensemble mean plots center this jet streak over northern IL / southern Lake Michigan / lower Michigan, with over 45 kt of southwesterly flow (likely much faster in reality, given the dispersion of model members).

Sheppard

AVIATION
Issued 300 AM CDT Tue Jun 17 2025

Thunderstorms are possible later this afternoon into the mid evening, especially for terminals across the southern portion of the area. Winds through the period modest from the west today.
Through the day today scattered to broken VFR CIGS are expected.
However overnight into Wednesday we will likely see MVFR CIGS push in with the low pressure system sliding in.

Kuroski

MARINE
Issued 300 AM CDT Tue Jun 17 2025

Low pressure will cross Lake Superior early this morning, and high pressure will settle into the Upper Midwest on today. Low pressure will cross eastern Iowa Wednesday morning and reach central Lower Michigan by Wednesday evening while strengthening.
High pressure will set up over the Plains Thursday, with the top of the ridge over Lake Superior and northern Lake Michigan.

Expect breezy southerly winds early this morning with highest gusts over the north half of Lake Michigan. Winds will become lighter and shift west later today. Lighter and variable conditions will return Wednesday, then become westerly Thursday.
While showers and thunderstorms are possible through much of the week, the time period with the best chance for storms is later this evening through Thursday morning.

Kuroski

MKX WATCHES/WARNINGS/ADVISORIES
WI...None.
LM...None.