545
FXUS63 KMKX 011924
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
224 PM CDT Mon Sep 1 2025

.KEY MESSAGES...

- Fog is possible again later tonight into early Tuesday
  morning, with patchy dense fog possible in low lying areas.

- Shower are likely (60 to 80 percent chances) with some
  thunderstorms later Tuesday night through Wednesday along a
  cold front.

- Below normal temperatures expected Wednesday night through the
  end of the week.

- Additional showers and a few storms are possible (30 to 60
  percent chances) Thursday night into Friday morning.

&&

.SHORT TERM...
Issued 224 PM CDT Mon Sep 1 2025

Tonight through Tuesday:

Scattered to broken diurnal stratocumulus clouds will linger
until sunset before dissipating. Light east to southeast winds
are expected.

High pressure to the east will keep dry conditions across the
area into Tuesday. Light to calm winds later tonight into early
Tuesday morning should allow for another round of shallow fog
along and west of the Kettle Moraine. Patchy dense fog may occur
in low lying areas, as the inversion may be a little stronger
than the past few nights and low temperatures dropping a few
degrees below the lowest dew points from this afternoon.

Another round of scattered to broken stratocumulus clouds are
anticipated by Tuesday afternoon, with light southwest to south
winds. Winds should turn southeast in the afternoon near the
lake in the afternoon with a lake breeze. Lows tonight should
be fall into the lower 50s, with highs Tuesday in the upper
70s.

Wood

&&

.LONG TERM...
Issued 224 PM CDT Mon Sep 1 2025

Tuesday night through Monday:

The cold front is expected to shift southeast toward the area
Tuesday night, then across the area Wednesday, exiting to the
southeast Wednesday night. This occurs as a deep 500 mb low
develops across south central Canada and shifts into western
Lake Superior. There is a good amount of upward vertical motion
and moisture with the front to work with, so have continued high
PoPs (60 to 80 percent or higher) for most of the area later
Tuesday night into Wednesday. There should be some thunderstorms
as well with the front, but moist adiabatic lapse rates yield
modest mean layer CAPE under 500 J/kg with modest deep layer
bulk shear around 20 knots or so. Thus, any storms should be
modest in nature. Precipitable water values in the 1.00 to 1.50
inch range should bring modest rainfall amounts and rates as
well.

500 mb cluster analysis continues to show the deep 500 mb low
lingering somewhere over Ontario Thursday into Saturday, with
the area within cyclonic flow and several vorticity maxima
pushing through. Forecast soundings are showing a relatively dry
airmass behind the front within cold air advection, so showers
may be tough to come by. There is reasonable agreement with
ensembles and models for a passing vorticity maximum and surface
cold front for another good chance (30 to 60 percent) for
showers and perhaps a thunderstorm.

Much cooler temperatures will occur behind the front Wednesday
night into the weekend, with record low maximum temperatures
around 60 degrees possible Thursday for Milwaukee and Madison.
Highs in the 60s and lows in the lower to middle 40s are
expected into the weekend.

500 mb flow should become more zonal by later in the weekend to
early next week, which should help to slowly moderate
temperatures. High pressure should bring dry conditions as well.

Wood

&&

.AVIATION...
Issued 224 PM CDT Mon Sep 1 2025

Scattered to broken diurnal cumulus clouds around 3500 to 4000
feet AGL should linger until sunset. Light east to southeast
winds are expected.

High pressure to the east will keep dry conditions across the
area into Tuesday. Light to calm winds later tonight into early
Tuesday morning should allow for another round of shallow fog
with 1 to 5 mile visibility along and west of the Kettle
Moraine. Patchy dense fog may occur in low lying areas.

Winds will become southwest to south on Tuesday, with southeast
winds with a lake breeze for terminals near Lake Michigan
Tuesday afternoon. More scattered to broken diurnal cumulus
clouds around 3500 to 4000 feet AGL should occur by midday into
the afternoon.

Wood

&&

.MARINE...
Issued 224 PM CDT Mon Sep 1 2025

High pressure around 30.1 inches will linger east of the region
into Tuesday, with light winds expected. Southwest winds will
become established by later Tuesday afternoon and increase
Tuesday night into Wednesday morning, as low pressure around
29.6 inches develops across Lake Superior.

The low will slowly move east toward the Ontario and Quebec
border Wednesday, dragging a strong cold front across Lake
Michigan. Gusty northwest winds will become established along
and behind the passing front Wednesday evening through Thursday
morning. Gale force gusts are not anticipated at this time.

Winds are forecast to turn west to southwest Thursday afternoon
and night and become gusty, as another low pressure system
around 29.4 inches develops somewhere across the western Great
Lakes region. The low will cross over or just to the north of
Lake Michigan during the day on Friday, resulting in a northwest
wind shift Friday night into Saturday. Periods of Small Craft
Advisory conditions are possible Wednesday into Friday across
the nearshore waters.

Showers are expected, with some thunderstorms, along the
advancing cold front Wednesday and Wednesday evening. A few
storms could produce gusty winds. Forecast trends will also be
monitored for waterspout potential during the day on Wednesday,
particularly across the northern half of the open waters.

Additional showers and a few thunderstorms will be possible
ahead of the second low on Friday. Whether or not gusty winds or
waterspouts will accompany this activity remains uncertain at
this time.

Wood

&&

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

$$

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