450
FXUS63 KMKX 051959
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
259 PM CDT Fri Sep 5 2025

.KEY MESSAGES...

- Gusty westerly winds will continue through Saturday evening,
  with highest gusts up to 30 mph during the afternoon hours.

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

- Some chances for showers and a few storms for middle to later
  portions of next week, though uncertainty exists.

&&

.SHORT TERM...
Issued 259 PM CDT Fri Sep 5 2025

Tonight through Saturday night:

Cyclonic flow will continue over the Great Lakes through
Saturday night as an upper level low sits over northern Ontario
and James Bay. This will give southern WI prevailing west-
northwest winds with gusts up to 30 mph at times, peaking in the
afternoon hours each day. Extensive cloud cover will also
continue, with maximums and a few light showers/sprinkles when
shortwaves roll across the area.

The first shortwave of interest is over eastern SD this
afternoon. This will track across southern WI late this evening
and we kept the mention of a slight chance of light showers
during this time. The next shortwave will arrive from central
and southeast MN Saturday afternoon. Given the time of day of
arrival, this one should have isolated to scattered rain showers
with it, and also some briefly higher wind gusts. Forecast
soundings show steep low level lapse rates but a shallow
convective cloud depth. Under these conditions, cold air funnels
can not be ruled out during the late afternoon.

Currently, cloud cover is diminishing due to dry air, but we can
expect an uptick in the sky cover overnight with the shortwave.
It will be a cool evening with a brisk westerly breeze, and
temperatures dropping into the lower 40s by morning. Highs
tomorrow will be in the lower 60s, similar to today. Clouds and
winds will diminish overnight Sat nt and allow for lows to drop
into the lower 40s once again.

Cronce

&&

.LONG TERM...
Issued 259 PM CDT Fri Sep 5 2025

Sunday through Friday:

The upper level shortwave trough and associated surface low
trough will shift east of WI on Sunday, but we will still be
stuck in northwest flow. The good news is that there will be
less cloud cover Sunday afternoon and night, allowing for
slightly warmer temps. With high pressure crossing the Great
Lakes and southerly flow returning to the Upper Midwest Monday
into Tuesday, the low level jet and moisture will also return.
There is a chance for showers and isolated storms Monday night,
primarily over the northwest half of WI. However, there are
differences between the models so we have a chance of storms in
the forecast over southern WI from Mon nt through Tue nt.
Overall, we will notice a warm-up with highs reaching the 70s.

For the latter half of the week, the upper level pattern is
uncertain. The chance for precip is low and the pattern favors
srn WI to remain on the warm side of a frontal boundary.

Cronce

&&

.AVIATION...
Issued 259 PM CDT Fri Sep 5 2025

Diurnal cumulus clouds will diminish this evening. Then clouds
with bases at or above 3500 ft and a few showers will be likely
over southern WI during the overnight hours as a shortwave
trough crosses the area. There may be an uptick in winds with
this feature, although they would be more noticeable just above
the surface.

Gusty west-northwest winds are expected once again during the
daytime hours on Saturday, along with VFR diurnal cumulus
clouds. A few showers are possible later Saturday afternoon into
the evening with another passing shortwave trough.

Cronce

&&

.MARINE...
Issued 259 PM CDT Fri Sep 5 2025

Brisk westerly winds will linger through tonight as low pressure
tracks across James Bay. The Small Craft Advisory ends late this
evening, but we will continue to monitor upstream wind trends as
a shortwave trough approaches from eastern SD. Brisk westerly
winds will ensue during the daytime hours on Saturday, then
shift to the northwest Saturday night into Sunday as high
pressure pushes through the region.

Some showers may occur at times over the northern portions of
Lake Michigan tonight through Saturday night, with a few
embedded thunderstorms. A few waterspouts may occur in this area
during this period.

Cronce

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 10 PM
     Friday.

&&

$$

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