NWS-Milwaukee/Sullivan Forecast Discussion
FXUS63 KMKX 052250
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
550 PM CDT Sun Jul 5 2026
.KEY MESSAGES...
- There are chances for showers and a few thunderstorms in south
central WI into the evening. Isolated cloud-to-ground
lightning would be the main impact with any activity.
- Moderate Swim Risk for beaches in Milwaukee (south half),
Racine and Kenosha Counties into this evening.
- Next chance for showers and thunderstorms is Wednesday
evening through Thursday evening.
&&
.UPDATE...
Issued 550 PM CDT Sun Jul 5 2026
Lake breeze combined with outflow boundary from afternoon storms
continues to fire scattered showers and a few rumbles of thunder
across south central portions of the CWA. Main concern would be
quick downpour and an occasional cloud-to-ground lightning
strike with this activity. However, should see this activity
linger for the next few hours, but as we lose daytime heating
gradually diminish further into the evening. Otherwise,
previous forecast remains on track with temps dipping down into
the 60s to upper 50s overnight as high pressure builds down into
the region for Monday.
Wagner
&&
.SHORT TERM...
Issued 301 PM CDT Sun Jul 5 2026
Rest of Today through Tuesday:
Steady north-northeast winds over Lake Michigan will bring wave
heights into the 2 to 4 foot range along the shoreline. There is
a moderate swim risk for Milwaukee, Racine and Kenosha Counties
today through late evening.
The weak mid level shortwave that is sitting over the Upper
Midwest is responsible for the isolated showers (slight chance
of thunder) over western WI and eastern IA. Areas west of
Madison have a chance for these isolated storms to pop up until
the sun starts setting, with surface based CAPE of around 1000
j/kg. The limiting factor for converge is a weak inversion, but
places are starting to meet the convective temperature now.
Meanwhile, southeast WI is entrenched in widespread cloud cover,
including a mix of low and high clouds. There is marine-
influenced air trapped in the low levels so cloud bases are low
(1000-2000ft). Surface convergence between these two areas is
helping a few showers develop in the Rockford area and they
could also develop toward Janesville.
The upper trough will finally exit tonight. Surface high
pressure will dominate the Upper Great Lakes through Tuesday
with a drier air mass in place. Dewpoints will fall into the 50s
to around 60 by late tonight, with temperatures not far behind.
Patchy fog is expected west of Madison, especially within the
Wisconsin River Valley.
Winds will remain steady out of the northeast Monday with
slightly warmer highs than today, but right around normal for
early July. Expect sunny skies. Monday night lows will be in
the mid 50s to around 60. Light and variable winds Tuesday will
allow for a lake breeze to develop in the afternoon. With plenty
of sunshine and weak return flow around the high, high
temperatures will generally get back into the lower/mid 80s.
However, cooler by the Lake Michigan shoreline and warmer toward
Wisconsin Dells.
Cronce
&&
.LONG TERM...
Issued 301 PM CDT Sun Jul 5 2026
Wednesday through Sunday:
A vorticity maximum or possible MCV will track from central MN
into the nrn Great Lakes on Wed, followed by a weak shortwave
trough tracking from the nrn Great Plains into nrn or central WI
through Thu. Swly sfc winds and warm advection will boost temps
into the middle to upper 80s on Wed. A slow moving sfc trough and
cold front will then pass from nw to se across the area late Wed
nt or Thu with some timing differences among the extended models.
Rain chances of 60-80 percent are forecast ahead of and along
the frontal passage, and could be in the mode of a MCS, typical
of summer.
Wnwly flow aloft is then expected for Fri through the weekend as
mean shortwave ridging is expected in the vicinity of the nrn
Great Plains to nrn Great Lakes. A weak shortwave trough may pass
to the south of this wave from the central Great Plains to the
Ohio Valley. Seasonal temps and humidity is expected during this
period with just 20 percent chances for showers and storms at
times.
Gehring
&&
.AVIATION...
Issued 550 PM CDT Sun Jul 5 2026
There are a few scattered showers across south-central WI early
this evening that may bring a brief light to moderate shower and
an occasional rumble of thunder to MSN and JVL, but chances
diminish through the evening ending around sunset. Outside of
some lingering MVFR ceiling in southeastern WI this evening,
mostly expecting VFR ceilings through the period as high
pressure begins to build across the region tonight through
Monday. Looking at light, northeasterly winds across much of
southern WI tonight, but cannot rule out some patchy fog for
areas west of I-39 corridor. Otherwise, high pressure continues
to influence the forecast into Monday with lighter northeasterly
winds through the day.
Wagner
&&
.MARINE...
Issued 301 PM CDT Sun Jul 5 2026
High pressure around 30.2 inches will remain in place over the
Upper Great Lakes through Tuesday. Expect steady north to
northeast winds through Monday and light and variable winds
Tuesday. Southwest winds will increase Wednesday as a cold front
approaches from the Northern Plains. Winds will become northerly
behind the front Thursday afternoon and night.
Cronce
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&
$$
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