612
FXUS63 KMKX 230329
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
929 PM CST Mon Dec 22 2025

.KEY MESSAGES...

- Temperatures continue to trend well above normal through the
  end of the week.

- Chances (about 30 to 50 percent) for light rain or drizzle in
  southeast Wisconsin Wednesday evening, with rain likely (about
  50 to 70 percent chances) area wide Christmas night.

&&

.UPDATE...
Issued 930 PM CST CST Mon Dec 22 2025

Dry air beneath the low stratus clouds overspreading southern WI
this evening has reduced drizzle accumulations to near zero up
to this point. Some ~30% drizzle chances remain in the forecast
over the next few hours for portions of eastern WI, but
Satellite clearly shows a rapid clear out in the low-level
clouds approaching from the west, which will cut off the drizzle
chances. Air temperatures are progged to remain above freezing
with any lingering drizzle this evening, with the potential to
drop near or just below freezing arriving long after the clouds
and slight drizzle chances are gone. Hence, freezing drizzle
concerns in the near term are much lower than prior
expectations.

Scattered to broken cirrus and cirrostratus clouds (at high
altitudes) will continue to pass through the region later
overnight, helping to reduce radiational cooling. A weak dry
cold front passes the region late overnight into Tuesday
morning, with a light northwesterly breeze developing later
Tuesday morning behind it. Some high altitude clouds linger, but
with ample sunshine for daytime highs to reach the upper 30s to
mid 40s across the region Tuesday.

Sheppard

&&

.SHORT TERM...
Issued 332 PM CST Mon Dec 22 2025

Tonight and Tuesday:

Steady warm air advection will continue into this evening,
before a weak cold front moves east through the area later
tonight. Most model forecast soundings continue to show a
fairly moist to saturated low level layer developing by early
this evening, with the middle to upper levels drying out and
removing ice crystals. Thus, drizzle is expected to move
through the area into this evening before ending later tonight
with the frontal passage.

There may be some light freezing drizzle as well over northern
portions of the area during this period, if temperatures can
drop to the freezing mark. There is some uncertainty if
temperatures will actually drop much tonight in this area before
the frontal passage, as the steady warm air advection may keep
temperatures relatively steady.

Temperatures will be close, so have kept in some light freezing
drizzle in the forecast for the northern parts of the area
north of Madison and Milwaukee. Will message this light freezing
drizzle potential with slick spots in the Weather Story
graphic. There may be some refreeze potential in this area as
well for the Tuesday morning commute, as temperatures remain
near freezing.

West northwest winds will then linger through Tuesday, with
perhaps some scattering out of the clouds by later in the day.
Highs will remain mild, from the upper 30s north to the lower to
middle 40s southeast.

Wood

&&

.LONG TERM...
Issued 332 PM CST Mon Dec 22 2025

Tuesday night through Monday:

The extended models have fairly good agreement for much of the
week but then diverge for the weekend as cyclogenesis may occur
over the Great Lakes and Ontario.

For Tue nt, a sfc ridge over nrn MN and adjacent Canada will
build sewd to the nrn Great Lakes and MI by 12Z Wed. Thus the
sfc ridge will shift across srn WI with temps dropping into the
20s for lows. Ssely sfc winds and warm advection will begin on
Wed as the high moves away and a wave of low pressure tracks
from the central Great Plains into the Ohio Valley through Wed
nt. In addition, another sfc trough will track across the nrn
Great Lakes and nrn WI during this time. Aloft a vorticity
maximum is expected to traverse across srn WI during this time
in conjunction with low to mid level warm, moist advection.
Either drizzle or very light rain may develop (30-50%) for Wed
evening over se WI with slight chances (20%) elsewhere. A weak
cold front will then follow.

Large polar high pressure will then follow across Ontario with
shortwave ridging aloft over srn WI on Thu. Nly winds will
shift ely but relatively mild temps will continue. For Thu nt, a
shortwave trough will track from the nrn Great Plains toward the
nrn Great Lakes, while at the sfc a wave of low pressure will
track from the central Great Plains across the nrn Ohio Valley
through Fri. The warm, moist advection will bring 50-70% chances
for rain late Thu nt, possibly lingering into Fri AM.

A more significant upper trough will then move ewd across srn
Canada inducing some degree of cyclogenesis over Ontario or the
Great Lakes for the weekend. There is wide spread with the
details, but strong cold advection and a polar airmass will
likely follow for Sat nt-Mon. Relatively mild temps continue
through Sat then much colder.

Gehring

&&

.AVIATION...
Issued 930 PM CST Mon Dec 22 2025

Some lingering ~30% drizzle chances in eastern WI over the next
few hours due to a lingering deck of low stratus (MVFR to Fuel
Alt MVFR ceilings present as of 9 PM CST). Satellite indicates a
rapid clear-out of the low-level clouds is approaching from the
west, and should restore most areas to VFR ceilings late tonight
(some SCT to BKN high-altitude cirrus / cirrostratus clouds
should remain in place). Light south winds veer west late
overnight, then northwest around 10 kt by late Tuesday morning
as a weak dry cold front passes through the region.

Dry weather and VFR with a light northwest breeze expected for
Tuesday. Some SCT to BKN high altitude clouds linger.

Sheppard

&&

.MARINE...
Issued 332 PM CST Mon Dec 22 2025

A Small Craft Advisory remains in effect into this evening from
Port Washington northward, mainly for elevated waves of 4 to 6
feet.

South winds this evening will shift southwest later tonight and
west on Tuesday, as low pressure around 29.8 inches moves into
Ontario. Winds will shift west northwest by Tuesday afternoon,
as high pressure around 30.4 inches moves from North Dakota into
northern Minnesota. Winds will subside Tuesday night, as the
high crosses Lake Michigan. These winds will shift out of the
southeast Wednesday, as the high moves east of the region.

Another stronger high around 30.5 inches will move east across
southern Manitoba into Ontario Wednesday night into Christmas
Day, with winds steadily increasing out of the northeast to
east.

Wood

&&

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

$$

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