178
FXUS63 KMKX 050243
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
943 PM CDT Thu Sep 4 2025

.KEY MESSAGES...

- Rain is likely (60-80% chances) this evening and overnight,
  particularly across the north.

- Widespread gales expected both in nearshore zones and over the
  open waters of Lake Michigan tonight into Friday morning.

- Below normal temperatures continue into this weekend. High
  temperatures slowly warm back up early next week.

- Latest model runs have introduced some periods of
  storms/shower chances from Tuesday through the end of next
  week.

&&

.UPDATE...
Issued 943 PM CDT Thu Sep 4 2025

A weak line of rain and sprinkles has move through ahead of the
main system/occluded front. This weak line of rain is mainly
latching onto some mid level WAA and upper level jet dynamics.
This weak line of showers currently stretching from Door County
to Dodge County continues to weaken as it moves east.

The more widespread rain is located along the occluded and cold
front that is moving east through tonight. Light to moderate
rain is expected as this low pivots through northern Wisconsin
into the UP of Michigan. The better chances for rain remains
north of I-94 where a more solid line to potentially scattered
line of showers will be. This is also the area with the best
lift. As the front moves through, the southern flank is
expected to weaken and become more isolated (this can already
be seen on satellite and radar). Southwestern Wisconsin
therefore will have a better potential for rain than south
central or southeastern. When looking at the larger picture the
difference ends up being a 50 % chance vs a 30% chance. Either
way the rain will largely be light with a couple tenths of an
inch of rain or less expected across southern Wisconsin.

Patterson

&&

.SHORT TERM...
Issued 220 PM CDT Thu Sep 4 2025

Tonight through Friday night:

Quiet weather through the rest of the daylight hours is
expected but another system swinging down through the region
will start to bring in some more widespread midlevel clouds.
This low pressure system will be strengthening with a strong
shortwave and a strong LLJ associated with it bringing strong
WAA. This system is expected to be fairly compact, quick-
moving, but strong with the pressure center around 992mb as it
pushes through northern WI overnight tonight. This will bring a
period of likely (60-80%) rain showers across the northern parts
of the CWA but keeping largely just chances from I-94 and
south.

Most may not even realize it rained because it will occur
overnight in large part and the quick moving nature of it (in
and out in just a couple hours) will keep rainfall totals
fairly low. There may be a lingering post- frontal chance for a
light shower or sprinkle into the day Friday associated with
some TROWAL type WAA aloft with some low level moisture but for
the most part Friday should be dry with clouds gradually
clearing out through the day. Otherwise expect breezy winds with
this system overnight lingering into the day Friday. High
pressure quickly returns to the area Friday night with winds
turning light and from the west.

Kuroski

&&

.LONG TERM...
Issued 220 PM CDT Thu Sep 4 2025

Saturday through Thursday:

High pressure will continue to build into the region Saturday,
with the high pressure center moving from the northern Central
Plains Saturday moving through the western Great Lakes region
for Sunday and then pushing out to the eastern Great Lakes for
Monday. This is all while the upper trough remains largely
in place through the weekend. Under the influence of this high
pressure and upper trough aloft below normal temperatures and
dry conditions are expected. Temperatures are expected to remain
in the 60s through Sunday before southerly winds return as large
scale ridging pushes back in from the west. We will then slowly
warm back up over the course of next week.

Models are in fairly good agreement through at least midweek
and there is certainly increased chances for showers/storms
Tuesday and Wednesday as latest model runs have started to
introduce shortwave activity Tuesday on the north side of the
ridge and then into Wednesday a stronger trough digging through
the eastern Great Lakes region squeezing the ridge back to the
west somewhat. At this point the upper trough looks to be a
glancing blow but may carry a frontal boundary with it that may
bring some precip chances. This will be short-lived, however,
as the ridging will push back in toward the end of the week.
This will not completely take out our precip chances as another
shortwave looks to ride the north side of the ridge through the
region Friday through Saturday, inevitably flattening out the
upper ridge.

Kuroski

&&

.AVIATION...
Issued 943 PM CDT Thu Sep 4 2025

MVFR to VFR conditions are expected through the period. BKN to
OVC skies are expected through Friday morning as a low pressure
system and frontal boundary move east northeast across the
state. Ceilings are around 5 to 7 kft and are expected to start
breaking up late Friday morning into the afternoon. A line of
rain is expected tonight and should clear southern Wisconsin to
the east during the early morning hours. Light to moderate rain
is expected with the best chances for rain being across central
and northern Wisconsin. Scattered to isolated showers will move
through southern Wisconsin. In the areas of moderate rain, which
are few and far between, slightly lowers ceilings around 3-5 kft
are expected with visibilities around 3-4 SM. LLWS will be
possible ahead of and along the frontal boundary as strong winds
aloft will have yet to mix down to the sfc. The LLWS is expected
to be around 45-50 kts at roughly 2 kft from the southwest. Both
the LLWS and rain is expected to end prior to sunrise.

Clouds will gradually become partly cloudy Friday afternoon
before becoming clear by Friday night. Winds will gradually
weaken Friday becoming light and southwesterly by Saturday
morning.

Patterson

&&

.MARINE...
Issued 220 PM CDT Thu Sep 4 2025

High pressure is weakening and pushing through the Ohio River
Valley, allowing winds to turn out of the southwest this
afternoon. Southwest winds will become gusty tonight as a low
pressure system approaches the northern parts of Lake Michigan
tonight. Widespread gale force gusts are anticipated across the
entirety of the open waters and nearshore waters, where a Gale
Warning is in effect between 1 AM and 10 AM CDT Friday morning.
Wind directions will shift out of the west- northwest during the
Gale Warning time frame as the low pressure crosses and moves
east of Lake Michigan. Breezy west winds will persist into
Friday night, weaken for Saturday before shifting to the
northwest for Sunday as high pressure pushes through the region.
A Small Craft Advisory will be needed following the Gale
Warning through at least the rest of the daylight hours Friday.
In addition its worth mentioning there will likely be a few
hours of small craft conditions in the lead up to the Gale
Warning tonight.

Rain is likely with the system tonight into Friday morning,
particularly over the northern two thirds of Lake Michigan.
Embedded thunderstorms are possible over the northern third of
the lake. Embedded thunderstorms will be capable of producing a
few waterspouts, particularly after midnight. Smaller chances
for more scattered rain showers and isolated waterspouts will
continue through Friday afternoon across the northern half of
the lake, with waterspout potential decreasing by the evening.

Kuroski

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Gale Warning...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
     LMZ565-LMZ567-LMZ643-LMZ644-LMZ645-LMZ646-LMZ669-LMZ671-
     LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
     LMZ876-LMZ878...1 AM Friday to 10 AM Friday.

&&

$$

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