NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 061903
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
203 PM CDT Sun Sep 6 2026

.KEY MESSAGES...

- Mild and pleasant weather continues through Labor Day.

- A High Swim Risk may develop for Lake MI beaches in Sheboygan
  and Ozaukee Counties for Tue-Tue evening.

- Warmer temps and higher humidity returns for Tue-Wed. There
  are 40-60% chances for showers on Tuesday mainly well north
  and west of the MKE metro area, followed by 60-90% chances for
  showers and thunderstorms Tuesday night, lingering into Wed
  AM.

&&

.SHORT TERM...
Issued 203 PM CDT Sun Sep 6 2026

Tonight through Wednesday:

Low level instability has resulted in broken cumulus
development well inland from the lake that will thin through the
afternoon. Otherwise another warm and pleasant day. High
pressure over the nrn Great Lakes will shift to the lower Great
Lakes for Labor Day and continue to support warm and pleasant
conditions. Some daytime camels can be expected but mid to high
clouds may also stream in from the west via a weakening upper
trough within a larger scale upper ridge.

The upper ridge to the west will then drift ewd across the wrn
Great Lakes into Mon nt 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 in the day. 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 203 PM CDT Sun Sep 6 2026

Wednesday night through Sunday:

The weak cold front will then pass on Wed followed by a sfc
ridge and pleasant conditions on Thu. Sly winds and warm,
moist advection will return by the end of the week with an
approaching sfc trough from the west. More substantial
cyclogenesis is possible on Sunday to the west. There are 20-40
percent chances for showers and storms Fri nt-Sun at this time.

Gehring

&&

.AVIATION...
Issued 203 PM CDT Sun Sep 6 2026

Sct-bkn035-040 this afternoon with local MVFR Cigs early this
afternoon. Otherwise VFR conditions tnt-Mon with the exception
of fog in the WI River Valley of sw WI for early Mon AM.

Gehring

&&

.MARINE...
Issued 203 PM CDT Sun Sep 6 2026

High pressure around 30.2 inches over the northern Great Lakes
today, shifting to the lower Great Lakes for Monday. Light and
variable winds are forecast through this period.

Increasing south to southwest winds are forecast for Tuesday
into Wednesday, shifting west to northwest Wednesday night into
Thursday, as a cold front moves toward and through the region.
Cannot rule out a few isolated gales on Wednesday across far
northern Lake Michigan.

A Small Craft Advisory will likely be needed Tuesday and Tuesday
evening north of Port Washington for breezy south winds and high
waves.

Gehring

&&

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

$$

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