NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 221205 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
705 AM CDT Sat Aug 22 2026

.KEY MESSAGES...

- Isolated thunderstorms possible late this afternoon in east-
  central and southeast Wisconsin.

- Dry and pleasant conditions Sunday into the beginning of next
  week. Storm chances return Tuesday evening into Wednesday.

&&

.UPDATE...
Issued 705 AM CDT Sat Aug 22 2026

There is still a window for a cluster of showers with a few
thunderstorms to track southward along the lakeshore of
southeast WI this afternoon, but it is shorter now, mainly
between 3 and 6 pm based on the latest meso models.

Basically, a potent little shortwave trough that is within a
broad upper trough stationed over Ontario and Lake Superior
will dive down through northern WI this afternoon. This will
usher a back door cold front down Lake Michigan and the
convergence along it may be enough of a trigger to generate
showers at a time when mid level lapse rates are steep. With
around 500 j/kg CAPE and fairly weak shear of 20 kt, this is
enough for isolated thunderstorms but not expecting severe. With
dry air in the low levels, a few wind gusts up to 40 mph would
be possible.

Cronce

&&

.SHORT TERM...
Issued 1030 PM CDT Fri Aug 21 2026

Tonight through Saturday night:

Quiet weather expected the rest of the night as storms have
dissipated or pushed out over the lake with no concerns with the
forcing and instability having pushed out as well. Dry
conditions largely expected through Saturday morning. Into
Saturday afternoon a backdoor cold front in combination with
some surface convergence along the lake breeze could bring some
additional shower and/or storm development into the early
evening. Chances remain fairly limited and only isolated
showers/storms are possible but the focus will be closer to the
lake and unlikely to impact any of western WI. Shear will be
limited and thus we do not expect storms to become strong.

Quieter weather will quickly return Saturday night as the front
slides out and higher pressure begins to nudge in.

Kuroski

&&

.LONG TERM...
Issued 1030 PM CDT Fri Aug 21 2026

Sunday through Friday:

Sunday will feature high pressure building into the region
keeping things dry through the day Tuesday. The high pressure
will begin to push out Tuesday night into Wednesday thus becoming
our next best chance for showers and storms as and 850mb front
and upper level shortwave swing through with some WAA, in
addition to the surface low and corresponding cold front. Still
some uncertainty in track and timing but models generally agree
on this pushing through bringing precip with likely some storms
as well. In addition, deep layer shear appears to be strong in
the 40-50kt range which would bring some severe risk if the
timing of storms is into the afternoon/evening with good daytime
heating.

After Wednesday, uncertainty increases a bit though in general
higher pressure seems to be pushing in and strengthening with
drier conditions overall more likely, possibly even into the
weekend.

Kuroski

&&

.AVIATION...
Issued 705 AM CDT Sat Aug 22 2026

Diurnal cumulus clouds with bases around 5000 feet are expected
across southern WI today, with the higher concentration toward
Lake Michigan in the afternoon. Look for isolated showers and
thunderstorms to roll down Lake Michigan this afternoon,
affecting Sheboygan to Milwaukee to Kenosha between 3 and 6 PM
(20Z to 23Z). Confidence is higher for Sheboygan to see a
thunderstorm than the other areas. Winds will remain steady out
of the northwest today through tonight, except become northerly
along Lake Michigan this afternoon.

Cronce

&&

.MARINE...
Issued 705 AM CDT Sat Aug 22 2026

Steady northwest winds are expected today as a low pressure trough
of 29.8 inches over Lower Michigan continues to exit. Then look
for gusty northerly winds to develop along a cold front that will
track from north to south down Lake Michigan this evening. A few
thunderstorms are possible along this front. Another cold front
will reinforce the northerly winds over Lake Michigan on Sunday
as low pressure around 29.6 inches tracks from Lower Michigan to
Ontario and high pressure of 30.2 inches pushes in from the Upper
Midwest. Variable winds are expected for Monday and Tuesday as
the high crosses the Upper Great Lakes.

&&

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

$$

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