273
FXUS63 KGRB 041747
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1147 AM CST Thu Dec 4 2025

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- Record or near record cold is expected today with a few
  locations possibly setting a record low or record low maximum
  for the date.

- There is a 50-80% chance winds will gusts over 30 mph north of
  Sturgeon Bay in Door County tonight. The highest chances will
  be near Deaths Door and Washington Island.

- There is a 40-80% chance of light snow Friday afternoon and
  evening. Snowfall amounts around an inch or less are expected.

- Below normal temperatures will continue through the weekend with
  moderating temperatures by the middle of next week, along with
  periodic chances for snow.

&&

.DISCUSSION...
Issued at 231 AM CST Thu Dec 4 2025

Short Term...Today...Tonight...and Friday

Lake effect snow will come to an end across the far north early
this morning, with dry weather expected as high pressure passes to
the south. High temperatures under the arctic airmass will be a
solid 20 degrees below normal as temperatures only reach 10 to 15
degrees during the afternoon. These cold high temperatures will
likely reach or exceed record low maximums for the day (see
CLIMATE section below).

As the high moves off to the east, some warm air advection will
cause increasing clouds tonight as temperatures initially fall
this evening, then slowly rise during the overnight hours. The
warm air advection may bring some light snow or flurries to far
north- central Wisconsin given the modest isentropic lift.

A cold front will drop south on Friday across the northern Great
Lakes, but stall and remain just to our northwest. However, a mid
level shortwave will track across the western Great Lakes on
Friday, which will bring the chance for light snow and flurries to
the region. The best chance for snow (40-70%) will be Friday
afternoon when moisture and lift will coincide with the Dendritic
Growth Zone at 600-700mb. Given the meager lift and fairly high
DGZ snowfall amounts are only expected to be a few tenths of an
inch with some locations possible reaching an inch. High
temperatures on Friday are expected to recover into the lower
20s.

Long Term...Friday Night Through Wednesday

A west-northwest flow at 500mb expected to continue into the middle
of December, with several clipper systems moving with the mean
flow over the next week, The continuation of below normal temperatures
will continue through the weekend with some moderation in the
temperatures by the middle of next week, although confidence is
low depending on the exact storm track of each clipper system. The
whisker plots for highs/lows in the model guidance indicated a
large spread beyond Monday to give low confidence in the amount
of moderation in temperatures.

For Friday night, the first clipper system will exit the area
during the evening. Per coordination with the short term
forecaster, did bump up snow probabilities Friday evening, while
snowfall amounts for the entire system have been bumped up from
the previous forecasts. The chances of snow showers will linger
through the night across the far north. Tranquil conditions
expected Saturday with next clipper system passing south of the
area Saturday night into Sunday morning. Model trends over the
last day or so has shown this system will impact our southern
counties with some light snow. Have modest chances for snow going
at the moment at 30-50% generally south of of Highway 29.
Attention then turns to a more potentially potent system Monday
afternoon and Monday night. The Canadian and ECMWF depict this
system, although the track is considerably different while the GFS
not showing much of a system. I usually trend to the
ECMWF/Canadian solution when the GFS does not match up. However,
the difference in the ECMWF/Canadian model solution leads to low
confidence in snowfall amounts. However, plenty of time to watch
how this will play out in the upcoming days.

Latest guidance off the GFS/ECMWF indicated temperatures moderating
by the middle of next week. With arctic air across Canada,
confidence is low in the amount of moderation in the temperatures
depending on the track of each clipper system,. At Green Bay, the
box whisker plots were showing a 10 degree spread Tuesday and
Wednesday on the max/min temperatures.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1146 AM CST Thu Dec 4 2025

Clear, cold, but good flying conditions are expected for the
afternoon to early afternoon period. Some mid to high clouds will
arrive through the afternoon but no ceilings are expected until
some lower clouds arrive overnight and bring some MVFR ceilings to
portions of north-central Wisconsin. As the lower clouds arrive,
some light snow will move into the region as well, although this
will mainly be limited to north-central Wisconsin during the
daytime period. Winds will be on the increase overnight as well,
which will spread some LLWS from west to east through the morning
period as well. Finally, the next round of light snow does appear
to delay towards the afternoon, but a few flurries may make their
way into portions of central Wisconsin and areas along the
lakeshore by around noon.

&&

.CLIMATE...
Issued at 231 AM CST Thu Dec 4 2025

Record or near record cold is expected today with a few locations
possibly setting a record low or record low maximum for the date.
December 4th (record low/year(s) & record low maximum/year(s)):

Antigo (-13/1985 & 8/1991), Appleton (-9/1940 & 14/1929,1942),
Green Bay (-8/1977 & 15/1976), Manitowoc (-2/1976 & 13/1976),
Marshfield (-16/1919 & 11/1972), Merrill (-23/1919 & 8/1976),
Oshkosh (-5/1977,1985 & 11/1991), Rhinelander (-22/1927 & 8/1972),
Stevens Point (-11/1902 & 10/1972), Sturgeon Bay (- 1/1940 &
12/1976), Wausau (-7/1991 & 12/1991), Wisconsin Rapids (-18/1940
& 9/1991).

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION.....Kurimski/Eckberg
AVIATION.......Uhlmann
CLIMATE........Eckberg