114
FXUS63 KMKX 080553
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1253 AM CDT Tue Sep 8 2026

.KEY MESSAGES...

- There may be a decaying area of showers and storms that
  approaches or moves into areas northwest of Madison this
  morning. This should continue to weaken as it moves further
  into the area.

- A period of showers and some storms will move across the area
  mainly later tonight into early Wednesday morning. An isolated
  stronger storm with gusty winds may occur. Locally heavy
  rainfall is possible as well.

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

&&

.SHORT TERM...
Issued 1253 AM CDT Tue Sep 8 2026

Today through Wednesday:

Convection over central Minnesota into northwest Iowa and to the
west is being driven by 850 mb warm air advection and the low
level jet. This activity is shown by the CAMs to slowly move
eastward overnight into early Wednesday morning. Some
disagreement with where this activity may move into this
morning, as some keep the activity to the north or west, with
others trying to bring it into areas northwest of Madison after
12Z to 13Z today.

The warm air advection does try to shift over into Wisconsin
this morning, so there may be some opportunity for this activity
to make it in the northwest parts of the area. It should be
weakening as it moves toward and into that area. For now, will
maintain 30 to 60 percent chances for showers and some storms
northwest of Madison this morning and watch trends.

Otherwise, kept generally 20 to 30 percent chances for showers
and some storms today in northern and western parts of the area,
as the warm air advection moves over the area. Forecast
soundings are showing dry low levels below 8000 feet AGL, so
think anything that tries to form will be high-based and may
struggle to reach the ground.

Warmer and more humid conditions are expected today, with highs
into the upper 70s north to the lower to middle 80s south. There
should be a southeast lake breeze near the lake this afternoon.

Moderate swim risk conditions are expected for Lake Michigan
beaches in Sheboygan and Ozaukee Counties this afternoon and
evening. South to southeast winds will increase, with building
waves of 2 to 3 feet. Think these waves will remain below 4 feet
at this time.

CAMs try to develop some stronger convection over northeast Iowa
by 00Z Wednesday, though it weakens considerably as it moves
east into southwestern portions of the area during the evening.
Forecast soundings continue to slowly saturate during the
evening, with tall skinny CAPE aloft. Thus, it may be tough for
showers and storms to develop in the evening.

Forecast soundings then saturate with moist adiabatic profiles
later tonight into Wednesday morning, with very tall and skinny
mean layer CAPE. The low level jet brings more moisture
transport into the area, with continued warm air advection.
Precipitable water values reach to or over 2.00 inches as
well. This suggests that mainly locally heavy rainfall would be
possible, along with an isolated strong storm with gusty winds.
Kept high chances (60 to 80 percent) for showers and some storms
later tonight into early Wednesday morning.

Most of the precipitation should exit the area by later
Wednesday morning, with dry conditions in the afternoon. The
main front may not move through until later in the afternoon,
but most of the moisture and upward motion will be east of the
area. Mild and humid conditions should linger into Wednesday, as
winds shift to the west.

Wood

&&

.LONG TERM...
Issued 1253 AM CDT Tue Sep 8 2026

Wednesday night through Monday:

High pressure dominates the region starting Wednesday night,
bringing dry and cool conditions to southern Wisconsin. Lows in
the 50s are expected Wednesday night, with some potential for
fog development under clear skies and very light winds.

High pressure slowly propagates eastward through Friday, with
southerly winds increasing into Friday, as a low pressure
system deepens in the northern Plains. Highs in the upper 70s
are expected both Thursday and Friday. As the low lifts into
northern Ontario, a cold front will sweep southeastward through
Wisconsin Friday night into Saturday, bringing the next chances
for thunderstorms. With the majority of this activity developing
overnight, severity looks to be highly limited (MUCAPE below
300 J/kg). PWATs of 1-1.50 inches are expected, so heavy rain
may become a hazard in areas that see multiple rounds of storms.

Aside from a few lingering showers on Saturday, dry conditions
look to prevail as low pressure quickly lifts through Hudson Bay
and the cold front stalls across the Ohio Valley. Highs in the
upper 70s to lower 80s are expected, with mostly dry conditions
continuing overnight. The next low pressure system looks to
develop in the lee of the Wyoming Rockies Saturday into Saturday
night, bringing increasing southeasterly winds into Sunday as
low pressure lifts into the northern Plains.

With warm frontogenesis developing across the area, broad lift
and instability builds into southern Wisconsin, leading to the
next chances for thunderstorms Sunday through Monday. The
evolution of this system remains in question, so exact
time frames and intensity of thunderstorms similarly contains
plenty of uncertainty. Modeling does converge on a solution of
the final round of storms along a cold front on Tuesday
afternoon, with a return to high pressure thereafter.

MH

&&

.AVIATION...
Issued 1253 AM CDT Tue Sep 8 2026

High clouds will continue to move southeast through the area
overnight into today. There may be some opportunity for a
weakening area of showers and storms to make it to areas
northwest of the Madison terminal after 12Z to 13Z today. It
should be weakening as it moves toward and into that area.

Otherwise, there are mainly small chances for showers and some
storms today in northern and western parts of the area. Forecast
soundings are showing dry low levels below 8000 feet AGL, so
think anything that tries to form will be high-based and may
struggle to reach the ground.

Light and variable winds overnight should become south today.
There should be a southeast lake breeze for terminals near the
lake this afternoon.

It may be tough for showers and storms to develop in the
evening across the area, with the low levels still dry. Showers
and some storms should move through southern Wisconsin later
tonight into early Wednesday morning, with locally reduced
ceilings and visibility values. Southwest winds are expected.
Left out mention of low level wind shear later tonight for now,
as conditions look borderline at best.

Most of the precipitation should exit the area by later
Wednesday morning, with dry conditions in the afternoon. The
main front may not move through until later in the afternoon,
but most of the moisture and upward motion will be east of the
area. Winds will shift to the west on Wednesday.

Wood

&&

.MARINE...
Issued 1253 AM CDT Tue Sep 8 2026

High pressure around 30.2 inches will remain well to the east of
the region today. Meanwhile, low pressure around 29.3 inches
will continue to move northeast through Manitoba into northwest
Ontario. This will allow for gradually increasing southerly
winds into tonight, especially over the north half of the lake.

As strong low pressure around 29.0 inches enters Hudson Bay
later tonight and Wednesday, winds shift southwest, then west on
Wednesday, as a cold front pushes southeastward through the
lake. A few gale force gusts may occur over far northern
portions of the lake Wednesday.

Winds become northwest behind the front, gradually weakening
Thursday and Thursday night with high pressure around 30.0
inches developing over the region. Winds shift to the south
again and increase into Friday, as a cold front moves into the
region from the west.

South to southeast winds and building waves will approach Small
Craft Advisory levels this afternoon and evening for areas north
of Port Washington. May see these conditions develop again
Friday afternoon and evening, for areas north of North Point
Lighthouse.

Wood

&&

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

$$

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