974
FXUS63 KGRB 012355
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
555 PM CST Thu Jan 1 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Bitterly cold wind chills between 10 below and 20 below zero can
  be expected late tonight into Friday morning.

- Light snow will end early this evening as a fast moving clipper
  system exits the region.

- Intermittent chances for light, fluffy snow through the weekend
  and into early next week as fast-moving clipper systems traverse
  the region. There is a 50 to 70% chance of at least 2 inches of
  snow across north-central and northeast Wisconsin Sunday
  afternoon into Sunday night.

&&

.DISCUSSION...
Issued at 129 PM CST Thu Jan 1 2026

A fast moving clipper system will bring light snow and flurries to
the region through early this evening and taper off as high
pressure builds in across the Upper Mississippi Valley.
Additional snowfall accumulations will be light, on the order of a
few tenths of an inch. The high will allow skies to clear out,
which will allow temperatures to fall overnight. Lows are expected
to fall into the single digits below zero across north-central
Wisconsin, around zero across central, and the single digits above
zero across east-central Wisconsin. Winds are not expected to die
off completely as the high itself will remain upstream, which
will allow wind chills to fall once again. Wind chills are
expected to range from 10 to 20 below zero across north-central
and central Wisconsin, with around 10 below zero across the rest
of the region. These wind chills will once again be above
criteria; therefore, a Cold Weather Advisory is not anticipated
for tonight.

The high will continue to hold across the upper Mississippi
Valley, which will keep temperatures cold across Wisconsin.
Despite sunshine, highs on Friday are only expected to rise to 10
to 15 degrees across north-central and much of central Wisconsin,
with middle teens across the rest of central, east-central, and
northeast Wisconsin.

The long term pattern features a stable synoptic setup with broad
mid-level troughing over eastern North America and a ridge over
the Rockies. This configuration places an 850mb thermal gradient
over the western Great Lakes, with northwest flow aloft steering
several fast-moving clippers across the region. The first system
arrives on Saturday, potentially bringing light, fluffy snow to
the area, with the highest probabilities near the Michigan border.

A more potent clipper is progged to track across the region
Sunday afternoon and Sunday night. Accumulations with this system
have continued to trend higher, with a 50 to 70 percent chance of
greater than 2 inches of snow across north-central and northeast
Wisconsin and a 30 to 50 percent chance of exceeding 4 inches
across the same area. Model soundings indicate precipitation may
taper off to freezing drizzle late Sunday night as the snow ends
from west to east and mid levels become dry; however, at that
point the snow will have already fallen. Therefore, the impact
from the freezing drizzle on the backend should be minimal.

Yet another system may target far northern Wisconsin Tuesday into
Tuesday night, though precipitation type may become an issue as
the core of the arctic air retreats into Canada. Temperatures will
remain below normal through the weekend before moderating to
above average levels by early next week.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 555 PM CST Thu Jan 1 2026

Light snow with prevailing VFR vsby will end across the region late
this evening. Cigs will be a mix of MVFR and VFR, lowest over central
and north-central WI. Overnight, clouds will slowly clear out, except
north of a line from RRL to IMT (including RHI) where MVFR cigs will
persist. On Friday, expect MVFR clouds to diminish over north-central
WI in the morning. Otherwise, it will be mostly clear with high clouds
increasing from the west.

Cloud forecast for tonight is lower confidence as there is still
a lot of broken to overcast skies upstream. Could see the clouds
persisting longer and have delayed the clearing trend by a few
hours central WI, and went ahead and kept them in all night north-
central.

West winds will remain below 10 kts tonight. West-northwest winds
increase slightly on Friday. Gusts to 15-18 kts will occur beyond
14z-15z.

Outlook...Additional light snow and MVFR potential returns Saturday
and Sunday.

&&

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

&&

$$

DISCUSSION.....Kurimski
AVIATION.......JLA

NWS GRB Office Area Forecast Discussion