023
FXUS63 KGRB 271116
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
516 AM CST Thu Nov 27 2025

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Lake effect snow will continue across Vilas County today into
  early Friday morning. Additional accumulations of 1 to 3 inches
  are expected, with localized amounts up to 6 inches possible in
  the northwest corner of the county.

- Blustery northwest winds will gust from 25 to 35 mph today, with
  gusts approaching 40 mph on the Door Peninsula. This may lead to
  blowing and drifting snow in open areas, particularly across the
  north.

- Confidence has held steady for accumulating snow on Saturday and
  Saturday night. There is a 60-90% chance for greater than 6
  inches of snow over central, east- central, and northeast
  Wisconsin, which may impact post-holiday travel.

- Much colder air will arrive for the start of next week. Wind
  chills may fall to 10 below zero or colder Monday morning.

&&

.DISCUSSION...
Issued at 252 AM CST Thu Nov 27 2025

The latest RAP analysis shows a potent mid-level cyclone spinning
over northern Lake Huron early this morning. This feature is
projected to lift northeast into northern Quebec later today,
though deep cyclonic flow will remain firmly established across
the western Great Lakes. Looking upstream, the next system of
interest, poised to impact the region this weekend, remains
offshore of the Pacific Northwest.

Short Term (Today through Friday):

Synoptic scale precipitation associated with the departing mid-
level cyclone will slowly diminish across northeast Wisconsin
today. This leaves lake effect snow showers over far north-
central Wisconsin as the greatest impact on sensible weather in
the near term.

Lake Effect Snow: Parameters are forecast to improve for a time
this morning as equilibrium levels rise to approximately 11 kft
and lake-to-850mb delta-Ts reach around 19 degrees Celsius. With
plenty of relative humidity remaining in the 850-700mb layer,
snow showers will persist over north-central Wisconsin into Friday
morning. Expect 1 to 3 inches of additional accumulation through
this period, with amounts possibly reaching 6 inches over the far
northwest corner of Vilas County. Given that snowfall intensity
looks to fall shy of warning criteria, will downgrade the Winter
Storm Warning to a Winter Weather Advisory (until 6 pm today).

Winds: A tight pressure gradient across the region will result in
a blustery Thanksgiving Day. Northwest winds will gust 25 to 35
mph at most locations, with the highest gusts reaching 40 mph over
the Door Peninsula. Will be considering ending the Wind Advisory
for Door County by 6 am. These winds will gradually subside this
afternoon through tonight as the gradient relaxes.

Rest of the Area: Outside of the lake effect belts, widespread
cloud cover will blanket the area under the deep cyclonic flow.
Scattered flurries could develop by late morning across the rest
of the forecast area as low-level lapse rates steepen. High
temperatures today will range from the middle 20s to lower 30s.
Some clearing is expected tonight over central to east-central
Wisconsin, allowing temperatures to fall into the teens to low
20s.

Long Term (Friday night through next Wednesday):

Attention turns to the storm system expected to impact the region
this weekend.

Weekend Storm: Guidance has shown a slight southward shift in the
track of the surface low due to pass across the region on Saturday
and Saturday night over the past 12 to 24 hours. Consequently,
probabilities of 6 inches or more of snow have decreased for areas
north of Highway 29. However, confidence remains relatively steady
south of a Wood County to Kewaunee County line, where
probabilities hold at 60 to 90 percent. While 50th percentile
snowfall amounts have decreased slightly in the NBM, signals
remain for an inverted trough extending up the west side of Lake
Michigan. This feature could generate a period of onshore flow
Saturday and Saturday night, potentially enhancing accumulation
totals over eastern Wisconsin due to lake enhancement and a deep
dendritic growth zone. Being on the northern edge of the system,
the southward trend is somewhat concerning regarding snowfall
placement. Given the forecast timeframe is just beyond the period
normally considered for a watch, will hold off on issuance after
coordination with neighboring offices.

Temperatures: High pressure builds into the region for later
Sunday through Tuesday, ushering in a period of chilly
temperatures. Forecast lows will likely need to be lowered due to
the anticipated fresh and widespread snowpack, particularly on
clear nights. Wind chills early Monday morning may approach 10
below zero at some locations. An arctic front looks to approach
the area by next Wednesday, bringing the next chance for snow.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 516 AM CST Thu Nov 27 2025

Scattered lake effect snow showers will continue over north-
central WI through the TAF period, which will impact RHI with
brief MVFR vsby at times. Isolated light snow showers or flurries
could impact the other terminals. Expect MVFR to low-end VFR
cigs to scatter out this evening.

Northwest winds gusting to 25-30 kts early this morning will
gradually subside through the TAF period.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM CST this evening for WIZ005.

Wind Advisory until 6 AM CST early this morning for WIZ022.
&&

$$

DISCUSSION.....MPC
AVIATION.......MPC