139
FXUS63 KMKX 310203
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
903 PM CDT Wed Jul 30 2025

.KEY MESSAGES...

- High swim risk through late Thursday night at all Lake
  Michigan beaches.

- Rain continues to taper this evening.

- Much more comfortable conditions expected through the second
  half of the week as drier air moves into the region.

- Humidity gradually returns early next week, along with shower
  and thunderstorm chances.

&&

.UPDATE...
Issued 903 PM CDT Wed Jul 30 2025

Forecast is on track this evening. Widespread rain is quickly
minimizing in coverage as high pressure begins to build into the
western Great Lakes from the Manitoba/western Ontario vicinity.
Northeasterly low level flow has increased ahead of the building
high, acting to push richer low level moisture south into
Illinois and Indiana. The increasing winds have also resulted in
rising wave heights at Lake Michigan beaches, where a Beach
Hazards Statement is now in effect. Expect that the low levels
will continue to dry as high pressure continues to establish,
resulting in gradually decreasing cloud cover through the
overnight period. Conditions will be hazy through the overnight
period as Canadian wildfire smoke arrives from the north.

Quigley

&&

.SHORT TERM...
Issued 310 PM CDT Wed Jul 30 2025

Tonight:

Cooler temperatures and widespread rainfall continues across
southern Wisconsin today. Weak low pressure is moving east
through the Ohio River Valley today, which has placed us in the
stratiform region of the rainfall. Instability and lift is
better to the south which is where all the thunderstorms are
residing. Can`t completely rule out a stray rumble of thunder or
two, but not anticipating anything more than that. With
northeast winds, little to no instability and drier air
beginning to move in, southern Wisconsin just doesnt have a
great environment for storms.

Rain will slowly end from the northwest to the southeast this
evening into tonight. Far southeastern Wisconsin may see light
rain linger into the early morning commute tomorrow as both this
weak low and the high pressure behind it are at a crawling pace.
Thankfully falling temperatures and dewpoints should help with
ending the rain. Overnight lows are expected to fall into the
mid 50s

Patterson

&&

.LONG TERM...
Issued 310 PM CDT Wed Jul 30 2025

Thursday through Wednesday:

The cooler and drier conditions are on the horizon for southern
Wisconsin. High pressure in the Northern Plains and Central
Canada will gradually move east southeast into the Great Lakes
Region starting Thursday. This low will slowly progress easterly
and be overhead around Saturday before its eventual crawl into
the New England States Sunday. Winds will remain light with
highs in the lower 70s to upper 70s through Sunday. Overnight
lows are expected to be in the low 50s to mid 60s. Those near
the lake shore will have a better chance for those mid 60s while
inland areas will be in the 50s.

As high pressure exits the Great Lakes Region Monday, winds will
return to southerly and temperatures will slightly increase
again. Highs Monday through Wednesday are expected to be in the
upper 70s to mid 80s as both temps and dewpoints increase. With
the return of the humidity brings the return of rain chances.
Now models are still all over the place as the main driver for a
lot of this rain early week will be shortwave troughs moving
through the larger flow. So chances are low around (10 to 25%)
and will largely be scattered to isolated coverage.

Patterson

&&

.AVIATION...
Issued 903 PM CDT Wed Jul 30 2025

Low CIGs are gradually improving this evening as high pressure
builds in from Canada & -RA pushes to the southeast of the
region. Anticipate CIGs to continue to improve through the
overnight period. Despite improving CIGs, flight categories will
continue to be hindered by arriving Canadian wildfire smoke and
attendant impacts on VIS readings. Have accounted for this
potential in the 21/00Z updates, with periods of MVFR VIS
reductions possible into Thursday afternoon.

Quigley

&&

.MARINE...
Issued 310 PM CDT Wed Jul 30 2025

North to northeast winds will persist across Lake Michigan
through Friday. Weak low pressure around 29.9 inches is moving
east through the Ohio River Valley today bringing showers and
thunderstorms to the southern half of the Lake. A few stronger
gusts with the thunderstorms will be possible across the far
southern end of the Lake, but not anticipating any severe level
wind gusts. Wind gusts of 20 to 25 kts will be possible across
the open water and nearshore zones. A Small Craft Advisory is
in effect this afternoon through tonight. Northeast winds will
also cause waves to build in the nearshores during this time.

High pressure around 30.3 inches will move into the western
Great Lakes from the Northern Plains Thursday. This area of high
pressure will slowly move eastward overtimes and be overhead
Saturday. Winds will light and variable across the lake much of
the day Saturday before becoming light south to southeasterly
Sunday afternoon as the high pushes into the New England States.

Patterson

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060-WIZ066-WIZ071-WIZ072
     until 4 AM Friday.

LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 4 AM
     Friday.

&&

$$

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