NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 192258
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
558 PM CDT Wed Aug 19 2026

.KEY MESSAGES...

- Patchy dense fog may occur overnight into early Thursday
  morning across parts of south central Wisconsin.

- Dry and pleasant conditions through Thursday with drier air
  in place.

- Shower/storm chances return Thursday night into Friday.

&&

.UPDATE...
Issued 559 PM CDT Wed Aug 19 2026

Lake breeze has initiated very isolated showers and storms in
southeastern Wisconsin, with storms dissipating quickly as lake
breeze influence moves inland and storms drift toward Lake
Michigan. Expecting any impacts to remain minimal. Overnight,
patchy fog with a few areas of locally dense fog are
possible under mostly clear skies and calm winds.

MH

&&

.SHORT TERM...
Issued 151 PM CDT Wed Aug 19 2026

Tonight through Friday night:

High pressure over the region is expected to slowly shift to
the southeast into Thursday, as northwest flow at 500 mb
lingers. This will bring a period of dry conditions with light
winds. There may be patchy fog overnight into early Thursday
morning in parts of south central Wisconsin, with patchy dense
fog possible in low lying areas. Lows tonight should drop into
the lower to middle 50s, with highs Thursday in the lower 80s.

Modest warm air and moisture advection in the low levels should
push into the area Thursday night into Friday, as winds shift
to the south and southwest. Weak low pressure moving east
southeast through the region should bring a cold front through
the area on Friday, exiting to the southeast Friday night. There
is a modest shortwave trough that may move through the area
Friday, though some models wash this feature out. Thus, most of
the upward vertical motion is in the low levels.

Forecast soundings are showing tall skinny mean layer CAPE with
modest deep layer bulk shear of 20 to 25 knots. This should
bring generally showers with widely scattered thunderstorms
later Thursday night and Friday. Kept 50 to 70 percent chances
for the showers west to east during this period, with the
chances for thunderstorms in the 20 to 40 percent range. The
southeast parts of the area would have better chances for
storms, with more daytime heating to tap into. Not seeing much
in the way of strong to severe storms at this time, but will
continue to monitor its potential in later forecasts.

High pressure should start to build into the area Friday night,
which should dry things out.

Wood

&&

.LONG TERM...
Issued 151 PM CDT Wed Aug 19 2026

Saturday through Wednesday:

Quiet and dry weather is expected to linger through the weekend
and early next week. Persistent upper-level northwesterly flow
along a ridge, combined with a surface high pressure system
over the Great Lakes region through Tuesday, favors these
conditions. High temperatures are predicted to be near normal
for the season, sitting in the upper 70s to lower 80s range,
with dewpoints in the lower 60s.

The next chance for precipitation is Wednesday (20 to 30
percent), as a surface low and accompanying cold front move
through the area.

Zawlocki

&&

.AVIATION...
Issued 559 PM CDT Wed Aug 19 2026

VFR conditions and light winds expected this evening, with an
easterly lake breeze across southeastern Wisconsin. Overnight,
winds become near calm and patchy fog will develop. Visibilities
in the 1-4 SM range are expected. Patchy dense fog (1/4 SM or
less) is possible in low lying areas such as river valleys.
Thursday morning, a return to VFR conditions as fog lifts
rapidly and winds become south-southwesterly. A southeasterly
lake breeze is expected for Lake Michigan terminals. Winds then
remain southwesterly through the overnight hours while cloud
cover increases. Still expecting VFR conditions to persist.

MH

&&

.MARINE...
Issued 151 PM CDT Wed Aug 19 2026

Light to modest winds are expected tonight into Thursday, as
high pressure around 30.0 inches tracks through the western
Great Lakes region. As the high exits to the southeast later
Thursday into Thursday night, south to southwest winds will
develop. Gusty southwest winds, as well as shower and
thunderstorm chances, return Friday into Friday night, as low
pressure around 29.8 inches moves across the region and drags a
cold front through. Gusty winds will shift to the northwest
later Friday night into Saturday after the front moves through.
High pressure around 30.2 inches moving into the region later in
the weekend may help maintain gusty north winds.

Wood

&&

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

$$

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