NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 041936
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
236 PM CDT Fri Sep 4 2026

.KEY MESSAGES...

- Isolated to scattered showers and thunderstorms will remain in
  the forecast this afternoon and tonight. There is a low
  probability for a strong or severe thunderstorm.

- Areas of dense fog will be possible late tonight and Saturday
  morning over Lake Michigan and over southern WI. Afterward,
  gradual lessening temperatures and humidity will be the trend
  for Labor Day Weekend.

- Very warm and humid conditions return next Tuesday and
  Wednesday along with chances for showers and thunderstorms.


&&

.SHORT TERM...
Issued 233 PM CDT Fri Sep 4 2026

Tonight through Labor Day:

Showers and storms continue over ne IA and sw WI due to
persistent, albeit weakening, low to mid level warm, moist
advection, but an outflow boundary is also in the vicinity. The
boundary extends east to west across nrn IL and then nwwd into
ne IA into sw WI. Despite sly winds returning along with more
sunshine and warming temps, do not expect enough of a recovery
to eliminate the MLCIN for late this afternoon and tnt for much
of srn WI, with the exception of sw WI. Any storms that
intensify over ne IA and sw WI would move into portions of south
central WI late this afternoon and evening and could be strong
or severe. In addition to this, a slow moving backdoor cold
front is still expected for the evening into the overnight as
the sfc trough across central WI shifts swd in response to a sfc
high building south through Ontario. Weak PVA will also drift
into srn and central WI ahead of a building upper ridge over the
Great Plains tnt. There are 30-40 percent chances for
thunderstorms this evening but will likely be elevated storms.
However, MUCAPE of 2000-3500 J/KG and mdt deep layer shear would
support a strong or severe storm if strong convective
initiation is realized. Overall, confidence is low in the
coverage and intensity of convection given weak forcing within a
high MUCAPE environment.

Immediately following the shallow and weak front, will be low
stratus and fog which will last well into Sat AM. Dense fog
will also be possible during this time. High pressure from
Ontario will then build into the nrn Great Lakes by late Sat
and slowly move to the lower Great Lakes for Sun nt-Mon. Thus
somewhat cooler temps, lower humidity, and nice weather is
expected through Monday.

Gehring

&&

.LONG TERM...
Issued 233 PM CDT Fri Sep 4 2026

Tuesday through Friday:

For Tue-Wed a strong upper trough and sfc low will track ewd
across far srn Canada. This will bring a return of sly winds and
very warm and humid conditions for Tue-Wed. The cold front is
expected to pass Tue nt or Wed AM with 50-60 percent chances for
showers and storms. Nwly flow aloft and sfc high pressure will
then prevail for Thu-Fri.


Gehring

&&

.AVIATION...
Issued 233 PM CDT Fri Sep 4 2026

VFR conditions the remainder of the afternoon but isolated
showers and storms will remain possible. A backdoor cold front
will then slowly track swwd across srn WI tnt-Sat AM, bringing
low stratus, BR, and fog with it. Initially, a few
thunderstorms may develop this evening as the front approaches
but fog and stratus will then follow. Cigs behind the front will
fall well below 1 fkt late tnt and not rise to MVFR Cigs until
late Sat AM. Widespread Vsbys of 1-2SM BR will develop behind
the front with areas of 1/2SM FG also expected. Dense fog is
possible. The fog and BR will mostly dissipate by late Sat AM
with MVFR Cigs dissipating during the 1st half of the afternoon.


Gehring

&&

.MARINE...
Issued 233 PM CDT Fri Sep 4 2026

Light winds over Lake Michigan will shift east northeasterly
tonight with the slow passage of a cold front. Areas of dense fog
may form over central and southern Lake Michigan after the frontal
passage and continue through Saturday morning. As high pressure
around 30.1 inches builds into the northern Great Lakes from
Ontario, modest northeast winds will develop for Saturday and
Saturday evening for central and southern Lake Michigan. Light and
variable winds are then expected on Sunday and Monday as the high
slowly moves from the northern Great Lakes to the lower Great
Lakes.

Gehring

&&

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

$$

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