121
FXUS63 KMKX 121623
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1023 AM CST Thu Dec 12 2024

.KEY MESSAGES...

- The Cold Weather Advisory has been allowed to expire as
  temperatures have risen above criteria. However, wind chills
  in the negative teens will linger until the early afternoon.

- The weekend low pressure area continues to trend on the warm
  side, with mixed precipitation and chances for freezing rain
  late Friday night and Saturday morning over south central WI.
  Then mostly rain over all of southern WI Saturday afternoon
  and night.

&&

.UPDATE...
Issued 1014 CST Thu Dec 12 2024

Winds ease slowly through today as arctic high pressure builds
into the area. While wind chills have risen above Cold Weather
Advisory criteria, chills between -5 and -10 will linger into
the mid afternoon.

Tonight, winds will calm as the center of the arctic high moves
overhead. While air temperatures will still be cold (around
zero), lower winds will keep wind chills and the air
temperatures relatively close to each other. A second Cold
Weather Advisory is not expected for tonight

CMiller

&&

.SHORT TERM...
Issued 346 AM CST Thu Dec 12 2024

Today through Friday:

The arctic air has arrived with wind chill temps of -12F to -25F
across srn WI early this morning. The areal extent of the Cold
Wx Advisory has not changed and is set to expire at 10 AM CST.
The sfc trough over the nrn Great Lakes will weaken today as the
large upper low over Ontario moves east. This will allow the
winds to weaken through the day, but arctic air will remain into
Fri AM. The arctic high over MN will settle over central WI by
12Z Fri then slowly move to the lower Great Lakes by 00Z Sat.
Temperatures will only rebound to 9-15F this afternoon but with
sunshine followed by low temps hovering around zero degrees.
Increasing sely winds and warm advection will begin Fri
afternoon with highs warming mainly into the 20s.

Gehring

&&

.LONG TERM...
Issued 346 AM CST Thu Dec 12 2024

Friday night through Wednesday:

There has been some delay in pcpn onset this weekend. Low to
mid level warm, moist advection will increase Fri nt-Sat nt as a
well developed shortwave trough and upper low moves from the
central Great Plains to nrn IL or srn WI. The associated sfc low
will remain fairly weak during this time. Nevertheless,
widespread pcpn is expected from west to east across srn WI Sat
afternoon, with some earlier pcpn west of Madison for early
Sat AM. Mixed pcpn including freezing rain and light ice accums
are forecast for south central WI through Sat AM. Temps will
then warm enough for mostly rain, but some snow will be possible
nw of Madison. The low pressure area will then exit Sun AM with
lingering showers possible.

Another upper trough will then approach again from the central
Great Plains for early next week but timing and strength
differences are abound. However, this will be a milder pattern
with better chances for rain rather than snow.

Gehring

&&

.AVIATION...
Issued 1019 AM CST Thu Dec 12 2024

VFR conditions will persist into tonight as an arctic high
pressure moves over the region. Northwest wind gusts will
gradually taper off through today, becoming light and variable
close to dawn on Friday as the high pressure center moves
overhead.

CMiller

&&

.MARINE...
Issued 346 AM CST Thu Dec 12 2024

The trough of low pressure over the northern Great Lakes will
weaken through the day, while high pressure around 30.5 inches
moves from Minnesota to across Lake Michigan on Friday. The gales
will end later this morning as well as the heavy freezing spray.
Winds and waves will continue to diminish into tonight.

The high will move east of the lake for Friday night into
Saturday, with breezy southeast winds developing. The breezy
southeast winds will shift due southerly and weaken for Sunday as
decaying low pressure approaches.

A Small Craft Advisory will be needed from Sheboygan to Winthrop
Harbor after the Gale Warning expires at 6 AM CST today. The
advisory will likely only be needed for the remainder of the
morning. Another advisory will likely be needed late Friday
night through Saturday night for breezy southeast winds and
building waves.

Gehring

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until noon
     Thursday.

&&

$$

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