NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 150607
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
107 AM CDT Sat Aug 15 2026

.KEY MESSAGES...

- Scattered showers & embedded thunder possible this morning.
  Best potential is along & south of I-94. Severe weather isn't
  expected.

- High Swim Risk today for Lake Michigan beaches in Milwaukee,
  Ozaukee, and Sheboygan counties.

- Additional chances for showers and thunderstorms through the
  weekend, but dry weather for most of it.

- Drier & more comfortable early next week, with storm chances
  returning by mid-week.

&&

.SHORT TERM...
Issued 100 AM CDT Sat Aug 15 2026

Today through Sunday:

The latest model guidance and satellite / radar trends affirm that
the vast majority of convection this morning will continue to
roll south of WI, predominantly impacting IL. A few stray cells
may lift and decay into southern WI, or even develop overhead
with the northern-most edge of the WAA, but coverage should
remain scattered to isolated. With MUCAPE 500 joules or less,
storms will be weak for our area. PWAT of 2" or greater could
make these showers efficient rain-makers, but the expected
sparse coverage and short lifecycle ought to limit
accumulations.

Some of the 00z CAM guidance depicts widely scattered showers
wrapping around the back side of the departed convective complex
this afternoon, yielding some continued slight rain chances for
southern WI this afternoon. Other guidance that doesn't show this
activity allows some gaps in the clouds to form this afternoon,
with a potential evening round of showers or even weak storms then
possible. In either case, should be minimally impactful unless
instability exceeds the current expectations (ex. the clouds part
early and additional sunshine makes it through).

A cold front crosses the region late tonight into early Sunday
morning, yielding widespread 25-45% chances for showers and
thunderstorms. By the time it arrives, MUCAPE should be generally
1500 joules or less (HREF mean is below 1,000 joules predawn),
which is plenty for some thunder, but with 0-6km bulk shear
generally 20kt or less predawn, the odds of strong to severe
storms are looking very low at this time. Chances decline
rapidly past daybreak Sunday, leaving predominantly dry weather
through the rest of Sunday. The initial wind shift + front will
leave the humid air (70 degree dewpoints) in place for Sunday,
and will allow some sunshine to make it through the clouds,
potentially allowing the southeast half of the CWA to briefly
reach 2,000 joules SBCAPE into midday Sunday, but by then the
surface front is far gone, along with the 500mb trough. Keeping
chances low (roughly 20% or less) for afternoon redevelopment.

Sheppard

&&

.LONG TERM...
Issued 100 AM CDT Sat Aug 15 2026

Sunday night through Friday:

A surface ridge of high pressure passes overhead early next
week, leading to dry and slightly less humid conditions.
Temperatures hold close to seasonal norms, dewpoints fall to the
low / mid 60s.

Chances for showers and thunderstorms return midweek as a cold
front / surface pressure trough sweeps eastward across the
midwest. High pressure builds into the midwest late in the work
week, yielding predominantly dry weather.

Sheppard

&&

.AVIATION...
Issued 100 AM CDT Sat Aug 15 2026

Predominantly dry weather and VFR ceilings for the next 2 hours
or so, followed by gradually decreasing cloud ceilings. There
is a chance (PROB30) for a cluster of scattered showers and a
few rumbles of thunder to push into southern WI at some point
this morning (see TAFs for best guess timing). Thunder
potential is too low for inclusion in the TAFs at this time, and
no strong storms are expected. Our best guess is for ceilings
to gradually fall to Fuel Alt MVFR levels through the course of
this morning, potentially some isolated IFR. Ceilings improve
but could remain predominantly MVFR into this afternoon. Other
model solutions include a VFR window this afternoon due to
lifting / scattering, but the associated sunshine then allows
some widely scattered rain showers with a few rumbles of thunder
to develop into this evening.

Expect a light east to southeast breeze developing through
today, becoming light and variable into tonight. A light
northwest breeze then arrives along a cold front late tonight
into Sunday morning, with chances (PROB30) for showers and a few
rumbles of thunder.

Sheppard

&&

.MARINE...
Issued 100 AM CDT Sat Aug 15 2026

Synopsis:
Periods of showers and storms continue over the southern half of
Lake Michigan today and tonight as a front remains stalled south
over Illinois and Indiana. Low pressure of 29.8 inches over Kansas
will track to the northeast this morning, then due east toward
southern Lake Michigan this evening. This low should help to bump
up winds and waves across the southern two thirds of Lake Michigan
through the daytime hours today, decelerating tonight as it closes
in. A cold front will then sweep across the lake late tonight into
Sunday morning, with chances for showers and weak storms. A light
northwest breeze arrives with the front into Sunday.

Beyond this system, a broad ridge of high pressure of 30.1 inches
will push into the Great Lakes early next week before another
potential front moves through the region midweek.

Nearshore Zones:
A Small Craft Advisory is in effect for zones north of North Point
Lighthouse from 8 AM to 7 PM CDT today due to breezy southeast
winds and high waves. Waves are expected to approach the 3 to 6 ft
mark. Winds are less certain, but should be between 10 and 20 kt
sustained with gusts up to 25 kt. Highest confidence in these
gusts is towards central Lake MI, adjacent to Sheboygan.

Sheppard

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060-WIZ066...8 AM Saturday
     to 7 PM Saturday.

LM...Small Craft Advisory...LMZ643-LMZ644...8 AM Saturday to 7 PM
     Saturday.

&&

$$

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