541
FXUS63 KMKX 102055
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
255 PM CST Wed Dec 10 2025

.KEY MESSAGES...

- May see some light snow occur into this evening in southwest
  portions of the area.

- A round of light snow may occur over portions of southern
  Wisconsin Thursday afternoon and night, with the better
  chances southwest of Madison. Any accumulations look to remain
  under one half inch in that area.

- Light snow showers may occur Friday afternoon and evening,
  with the passage of an Arctic cold front.

- An Arctic airmass is expected this weekend, with wind chills
  as cold as 15 below to 30 below zero for the overnight and
  early morning hours.

&&

.SHORT TERM...
Issued 255 PM CST Wed Dec 10 2025

Tonight through Thursday night:

An area of light snow may clip areas southwest of Madison into
this evening, as a sheared vorticity maxima at 500 mb may bring
enough differential CVA. It will battle some fairly dry air in
the low levels, so not expecting any accumulations or impacts
from this system.

There may be some clearing overnight into Thursday morning in
northern and eastern portions of the area, as high pressure
moves in and subsidence helps erode some of the low clouds. This
should allow for lows to drop into the single digits over most
of the area, coldest in the clearing areas. Wind chills may get
into the single digits below zero.

Middle to high clouds will move back in by Thursday afternoon.
An 850 mb low and associated frontogenesis response passing to
the southwest of the area later Thursday into Thursday night
will bring an area of light snow across Iowa into northern
Illinois, with the northern end of this possibly moving across
portions of southern Wisconsin. The better chances will again be
southwest of Madison Thursday evening. Forecast soundings
suggest moisture is modest but sufficient for some light snow.

Ensembles continue to keep just the northern end of this light
snow moving across far southern Wisconsin during this period,
with the 18Z NAM now backing off in this direction toward the
12Z GFS and ECMWF. Followed this trend in the forecast, with the
60 percent chances just in far southwest parts of the area. Any
snow accumulations at this time look to be one half inch or
less, mainly southwest of Madison.

Wood

&&

.LONG TERM...
Issued 245 PM CST Wed Dec 10 2025

Friday through Wednesday:

Will be sitting in a prevailing upper-level northwesterly flow
pattern through the end of the week into the weekend. Mid-range
models continue to show waves of energy embedded within this
pattern and trekking across the region periodically through the
weekend. May see some lingering light snow into Friday morning
as a shortwave trough works it way east across the Great Lakes,
as the surface low lifts up the Ohio River Valley.

Then another lobe of mid-level vorticity begins to work its way
down across the Upper Midwest later Friday as the cold air
begins to advect down into the region. Could see another round
of light snow from this initial lobe. Then the main trough and
energy is expected to work its way across Wisconsin into
Saturday, but given the increasing subsidence with the building
Arctic high, it may limit the potential for additional snow
showers.

The main story of this weekend will be the bitter Arctic
airmass arriving with the weekend system beginning late Friday
night. There is a consistent and persisting signal between the
NBM as well as the EPS and GEFS ensembles for single digit high
temps Saturday and Sunday, with near zero to sub-zero temps
overnight, especially Saturday night into Sunday.

However, with the 1040mb-ish high pressure building down the
Upper Mississippi River Valley and low pressure sitting off the
East Coast, it will be brisk and there will be higher potential
for negative teens to negative 20s wind chills Friday night
through Sunday, especially during the overnight hours this
weekend. If this trend continues, then could see the first
Extreme Cold headlines for the season this weekend.

Fortunately, this bitter cold pattern is looking brief, as the
WPC Cluster Analysis supports a 500mb ridge to build into the
region for the start of next week. Thus, with the warm air
advecting back into the area, trends suggest temps to warm back
to near normal by the middle of next week.

Wagner

&&

.AVIATION...
Issued 255 PM CST Wed Dec 10 2025

An area of light snow may clip areas southwest of Madison into
this evening. It will battle some fairly dry air in the low
levels, so not expecting any accumulations or impacts from this
system.

Ceilings may bounce around between 1000 and 3500 feet AGL into
this evening, perhaps more in the 1000 to 2000 foot AGL range by
later this evening. There may be some clearing overnight into
Thursday morning in northern and eastern portions of the area,
as high pressure moves in and subsidence helps erode some of the
low ceilings.

Gusty northwest winds are expected to gradually weaken tonight,
becoming light and west to southwest on Thursday and light out
of the east Thursday night.

Middle to high clouds will move back in by Thursday afternoon.
An area of light snow may move across portions of southern
Wisconsin later Thursday into Thursday night. The better chances
will be southwest of Madison Thursday evening. Any reduced
visibility and ceilings should remain southwest of Madison at
this time, with snow accumulations generally one half inch or
less in this area.

Wood

&&

.MARINE...
Issued 255 PM CST Wed Dec 10 2025

North to northwest gales will linger until early this evening
across the southern two thirds of Lake Michigan. These winds
will gradually diminish tonight into Thursday, as high pressure
around 30.1 inches moves in from the northwest.

A Small Craft Advisory is in effect for the nearshore waters of
Lake Michigan until midnight CST tonight for lingering gusty
north to northwest winds and elevated waves.

A period of west to northwest gales may return Friday night
into Saturday night, as a strong Arctic cold front moves through
the region. Heavy freezing spray may also develop during this
period, as the colder airmass moves in. A Small Craft Advisory
is likely for the nearshore waters this weekend into early next
week as well.

Strong high pressure around 30.8 inches will then move
southeast through the region Sunday and to the south early next
week. Gusty winds may return early next week.

Wood

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Gale Warning...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-
     LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
     LMZ876-LMZ878 until 6 PM Wednesday.

     Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until
     midnight Thursday.

&&

$$

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