442
FXUS63 KGRB 261145
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
545 AM CST Fri Dec 26 2025

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Hazardous travel continues across north central, far northeast
  and parts of central Wisconsin this morning due to lingering
  impacts of freezing rain. Locally dense fog may also occur.

- Light freezing rain may result in locally hazardous travel
  across northern Wisconsin Saturday night into Sunday morning.

- Significant snow accumulations are possible Sunday night into
  Monday, especially over north central and parts of central and
  far northeast Wisconsin.

- Strong northwest winds gusting to 30 to 45 mph inland, and gale
  force gusts to 35 to 45 knots on Lake Michigan, are expected
  from late Sunday night through Monday evening.

- Mild weather persists through the weekend, followed by much
  colder temperatures next week.

&&

.DISCUSSION...
Issued at 408 AM CST Fri Dec 26 2025

Two main areas of precipitation were ongoing this morning, one
associated with a short-wave trough over northern WI, and another
with convective elements (and nearby thunderstorms) over the
southeast part of the forecast area. Surface temps and wet-bulb
temps were at or below freezing roughly north of a line from
Marshfield to Sturgeon Bay, where freezing rain and light icing
was occurring. Farther south, mainly rain was observed.
Contemplated removing Waushara and Waupaca counties from the
advisory due to warming temps, but couldn`t rule out the
possibility of light icing still occurring in the northwest
portions of those counties, so erred on the side of caution and
left them in. Most of the precipitation will end from west to east
between 12z-15z, but given the possibility of icy conditions
lingering on any untreated secondary roads, have opted to not
change expiration times. It is conceivable that several counties
may get cancelled early. Areas of fog will also develop over much
of the area early this morning, with improving conditions
occurring in the late morning and afternoon.

High pressure brings a brief period of dry weather this afternoon
and tonight, and despite developing southerly return flow on
Saturday, most of that day should remain dry too.

Impacts of the incoming weekend system begin Saturday night, with
pre-frontal WAA leading to light rain, with potential for
freezing rain and light icing across northern WI. A strong upper
level trough will approach from the Northern Plains on Sunday and
Sunday night, with a deepening low pressure system lifting
northeast from Kansas into Lower Michigan. Models have trended
much higher with QPF/snowfall on Sunday night, leading to the
possibility of significant snowfall accumulations, especially over
the northwest half of the forecast area. In addition, strong
northwest winds may gust to 30 to 45 mph inland, with gale force
gusts reaching 40 to 45 knots on Lake Michigan. The cold and
strong northwest flow will likely boost snowfall totals across
north central Wisconsin and possibly Door County through Monday.

A clipper low pressure system may impact the region Tuesday into
Tuesday night, with some light snow accumulations over northern
WI. Lake-effect snows may develop in the wake of this system,
mainly over north central WI Wednesday into Wednesday night. Dry
conditions look to return late in the week.

Mild temperatures persist through the weekend, but drop
significantly by early next week (highs in the middle teens to
middle 20s), and again during the mid to late week (highs in the
single didgits and teens).

&&

.AVIATION...for 12Z TAF Issuance
Issued at 529 AM CST Fri Dec 26 2025

Most of the steadier rain and freezing rain has shifted east
early this morning, though widespread drizzle, fog and low clouds
covered the region. The drizzle should taper off from west to east
between 14z-16z, but low clouds (IFR/LIFR) will remain. The big
question is how much improvement will be seen during the day.
Given that low-level moisture is expected to persist through
tonight, and winds will be light, not expecting much change to sky
cover other than a modest increase in ceiling heights. Fog should
dissipate in most areas by afternoon, but could return over NC/C
WI tonight.

Light and variable winds will become northwest this afternoon,
then light east to southeast later tonight.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon CST today for WIZ005-010>013-
018-019-021-073-074.

Winter Weather Advisory until 9 AM CST this morning for WIZ020-
022-030-031-035>037-045.
&&

$$

DISCUSSION.....Kieckbusch
AVIATION.......Kieckbusch

NWS GRB Office Area Forecast Discussion