NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 071845
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
145 PM CDT Mon Sep 7 2026

.KEY MESSAGES...

- Moderate swim risk conditions are expected for Lake MI beaches
  in Sheboygan and Ozaukee Counties Tuesday afternoon and
  evening.

- Showers and storms are expected to develop as warmer, more
  humid air moves in Tuesday into Tuesday night. These storms
  will be capable of producing heavy rain and lightning. A few
  may become capable of producing damaging winds, but confidence
  is not high at this time.


&&

.SHORT TERM...
Issued 145 PM CDT Mon Sep 7 2026

Tonight through Wednesday:

Upper ridging will continue from the Upper MS River Valley into
the wrn Great Lakes through tnt, then flatten as it moves to
the east on Tue. Weak low to mid level warm, moist advection can
be expected while PWATs rise to 1.8-2.0 inches late on Tue. The
CAMs suggest a weakening MCS will move into south central WI
from wrn WI in the morning and continue to weaken as it attempts
to move into se WI in the afternoon. Only mid level saturation
and high based instability is expected. 40-60% chances for
showers are forecast on Tue mainly well north and west of the
MKE metro area, including the Madison area.

The main moisture plume and slightly better mid level lapse
rates will then shift into srn WI Tue nt ahead of the
approaching weak cold front that trails from strong low pressure
over far nrn Ontario or Hudson Bay. MUCAPE will still remain
limited but lift and moisture will still support shower and
storm chances of 60-90%, with some showers and storms lingering
into Wed AM. It is possible the showers and storms could develop
to the west over IA where an effective warm front will stall
with the convective activity then moving east into nrn IL and
possibly srn WI. Overall the severe thunderstorm threat looks
very low with possibly more of a heavy rain and urban and small
stream flooding potential, albeit still low at this time.

Gehring

&&

.LONG TERM...
Issued 145 PM CDT Mon Sep 7 2026

Wednesday night through Monday:

Weak cold advection is expected Wed nt followed by a broad sfc
ridge on Thu. A shortwave trough will also pass on Thu but the
airmass is too dry for many clouds or rain. Sly winds and warm,
moist advection will return for Fri ahead of a weak shortwave
trough, which will pass Fri nt. There are 30-50 percent chances
for showers Fri nt then 20-30 percent Sat AM with the cold
frontal passage.

More substantial cyclogenesis is then possible Sun nt into Mon
from the central Great Plains into the nrn Great Lakes. There
are 40-50 percent chances for showers and storms during this
time. Temperatures from mid week into early next week will be
near seasonal normals.

Gehring

&&

.AVIATION...
Issued 145 PM CDT Mon Sep 7 2026

Few-sct035-40 cumulus this afternoon with brief periods of
bkn035-040 well inland from Lake MI. VFR conditions will
then continue tnt-Tue. Middle to high based clouds and showers
are likely well north and west of the Milwaukee area on Tue.


Gehring

&&

.MARINE...
Issued 145 PM CDT Mon Sep 7 2026

High pressure around 30.2 inches will remain over the lower
Great Lakes through Tuesday. Meanwhile, low pressure around
29.6 inches over the northern High Plains will lift northward
through the Canadian Prairies into Tuesday morning. This will
allow for gradually increasing southerly winds late tonight
through Tuesday night especially over the north half. As low
pressure enters the Hudson Bay late Tuesday night and Wednesday,
winds shift southwesterly, then westerly on Wednesday as a cold
front pushes southeastward through the Lake. Winds become
northwesterly behind the front, gradually weakening through
Thursday and Thursday night. Winds shift to southerly again and
increase into Friday as low pressure develops in the northern
Plains.

Gehring

&&

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

$$

Visit us at weather.gov/milwaukee

Follow us on Facebook, X, and YouTube at:
www.facebook.com/NWSMilwaukee
www.x.com/NWSMilwaukee
www.youtube.com/NWSMilwaukee