949
FXUS63 KMKX 060311 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
1011 PM CDT Sun Oct 5 2025

.KEY MESSAGES...

- Showers (40 to 80 percent) and a few thunderstorms are
  forecast later tonight into Monday night with a slow-moving
  cold frontal passage. The highest chances would be Monday
  night in far southeast Wisconsin.

- Gale Warning remains in effect for the northern third of Lake
  Michigan open waters through the early overnight hours.

- A Small Craft Advisory remains in effect into early Monday
  morning for gusty south winds and building waves along Lake
  Michigan.

- Cooler, more seasonal and closer to normal temperatures
  return for the middle of the week.

&&

.UPDATE...
Issued 1011 PM CDT Sun Oct 5 2025

Showers and thunderstorms are ongoing along a slow-moving cold
front this evening. They extend from southwest Kansas through
central Iowa and into the La Crosse and Eau Claire areas. There
is still a question about if they will hold together through the
overnight hours when the front inches into central and south
central WI. The forcing mechanism is low level frontogenesis,
which is forecast to weaken overnight as it gets into south
central WI. There is also an enhanced area of fgen in the
600-700mb level that is currently over Kansas and that will
track northeastward along the front. By mid morning, the mid
level fgen will be over eastern Iowa and central WI.

It is still looking like the more widespread (but still
scattered) showers with a chance of lightning will occur over
southern WI between 3 PM and 10 PM, with a chance of lingering
light rain through the early overnight hours.

Cronce

&&

.SHORT TERM...
Issued 255 PM CDT Sun Oct 5 2025

Tonight through Monday night:

Gusty south winds will linger into early this evening, as the
pressure gradient remains tight and low level mixing continues.
Gusts of 30 to 35 MPH are expected at times. The winds should
slowly weaken this evening and overnight, as the cold front
approaches from the northwest.

Models continue to bring the cold front southeast toward the
northwest parts of the area later tonight and through the area
on Monday, shifting southeast by Monday evening. Showers (40 to
60 percent chances) and a few storms should gradually weaken as
they shift southeast into northwest parts of the area later
tonight into Monday morning. A lull in the activity is then
expected Monday morning.

More showers (30 to 50 percent chances) and a few storms
develop in southeast parts of the area Monday afternoon and
shift southeast during the evening. The areal coverage of the
showers may be greatest Monday evening, which has the highest
forecast PoPs (40 to 80 percent) at this time.

However, there is not much upward vertical motion besides the
low level frontogenesis response and perhaps some upper
divergence to work with. Forecast soundings are showing just
enough moisture, and instability is fairly weak in the
southeast parts of the area Monday afternoon.

CAMs have scattered showers and some storms developing by later
Monday afternoon mainly around or just southeast of the Kenosha
County area. For now, will leave in the higher PoPs Monday
night in the southeast, but may need some adjustment downward
in later forecasts, depending on where the development occurs.

Temperatures will remain warm ahead of the front tonight into
Monday, with 70s to near 80 degrees in southeast Wisconsin.
Temperatures should be in the 60s behind the front on Monday.
Cold air advection on weakening north to northwest winds Monday
night should bring in more seasonable temperatures.

Wood

&&

.LONG TERM...
Issued 255 PM CDT Sun Oct 5 2025

Tuesday through Sunday:

Generally west northwest flow at 500 mb is anticipated across
the region for the middle to later portions of the week per
cluster analysis forecasts, with positive anomalies over most of
the north central parts of the country. Strong high pressure
should shift slowly east across the region Tuesday into
Wednesday night and Thursday, which should bring dry conditions
and temperatures closer to seasonal normal values.

Ensembles are suggesting above normal temperatures returning to
the region later in the week and into next weekend, as a 500 mb
ridge axis shifts into the region. The signal for precipitation
during this period is weak, so the current small chances (20
percent or so) for showers later in the week may not
materialize.

Wood

&&

.AVIATION...
Issued 1011 PM CDT Sun Oct 5 2025

The southerly winds decoupled quickly at sunset, so low level
wind shear conditions are expected with 2000 foot AGL winds
from the south southwest around 40 to 45 knots. Winds will
weaken and shift northwest to north Monday, as the front moves
southeast through the area.

There is a line of showers and thunderstorms ongoing over
central Iowa and western WI this evening. This line should
weaken/break apart as they shift into central and portions of
south central WI later tonight into Monday morning. A lull in
the activity is then expected, before more showers and a few
storms develop in southeast parts of the area Monday afternoon
and shift southeast during the evening. May see locally reduced
visibility values with any showers and storms. A period of
ceilings of 1500 to 3000 feet AGL may occur Monday along the
frontal passage.

Wood/Cronce

&&

.MARINE...
Issued 255 PM CDT Sun Oct 5 2025

Gusty south winds are expected across Lake Michigan into
tonight, as strengthening low pressure around 29.3 inches moves
northeast into Ontario. The strongest winds will be across the
northern third of the open waters, where gale force gusts are
expected. A Gale Warning remains in effect for this area.

Otherwise, the rest of the lake will see southerly gusts up to
30 knots into tonight. A Small Craft Advisory is in effect for
the nearshore waters of Lake Michigan into tonight, for gusty
south winds and building waves.

Winds are expected to shift to the southwest and gradually weaken
into early Monday morning, ahead of an approaching cold front.

A northerly wind shift is expected through the day Monday behind the
cold front, and is expected to push south of Lake Michigan by
Monday night. High pressure around 30.4 inches should quickly
build in behind the cold front for Tuesday into Wednesday,
bringing light winds.

Wood

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Gale Warning...LMZ261-LMZ362-LMZ364-LMZ563 until 2 AM Monday.

     Small Craft Advisory...LMZ643 until 7 AM Monday.

     Small Craft Advisory...LMZ644-LMZ645-LMZ646 until 4 AM Monday.

&&

$$

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