751
FXUS63 KGRB 251115
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
515 AM CST Tue Nov 25 2025

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- A Winter Storm Warning has been issued for north-central
  Wisconsin from late tonight through early Thursday morning.
  Heavy snow of 6 to 12 inches is expected, with locally higher
  amounts in excess of 18 inches possible in the northwest corner of
  Vilas County.

- A Winter Weather Advisory has been issued for Lincoln and
  Langlade Counties for 3 to 5 inches of snow and hazardous travel
  conditions. Additional winter weather headlines may be needed
  for counties further south and east across central and far
  northeast WI.

- Strong northwest winds gusting 35 to 45 mph will develop on
  Wednesday. This will lead to blowing and drifting snow in the
  winter headline areas and difficult driving conditions for high
  profile vehicles across the entire area. Isolated power outages
  are possible.

&&

.DISCUSSION...
Issued at 344 AM CST Tue Nov 25 2025

The latest RAP analysis shows a rather energetic pattern shaping up
across the northern lower 48. Various shortwaves are moving east
from northern Missouri to southwest Wisconsin early this morning,
while the most dynamic shortwave is tracking east across southeast
Montana. At the surface, low pressure is gathering strength over
the western Dakotas, with an associated frontal system stretching
northeast across north-central Wisconsin.

As this low pressure tracks east and intensifies over Wisconsin
tonight through Wednesday, the focus of this forecast revolves
around highly impactful winter weather during one of the busiest
travel days of the year.

Short Term...Today through Wednesday Night

Precipitation Trends: Weak lift is occurring across Wisconsin
within a 900-800mb convergent zone and modest warm/moist advection
early this morning. This convergence is leading to a band of
light rain over central, north-central, and far northeast WI, with
pockets of lower visibilities. Rainfall will be focused along the
relatively stalled front across north-central WI today, while
spottier showers or drizzle could occur further south in the
broad, weak warm advection pattern. Expect an overcast day with
little change in temperatures, ranging from the upper 30s to upper
40s.

The low continues to intensify as it tracks across north-central
and far northeast WI tonight. Strong QG and frontogenetical forcing
will accompany the low, leading to widespread precipitation across
the area. The heaviest precipitation is forecast to occur within
the trowal airstream over north-central WI. While thermal profiles
look too warm for snow initially in the evening, strong lift and
heavy precipitation rates combined with northeast winds advecting
in colder air should lead to a gradual transition from rain to
snow starting around mid evening over Vilas county and reaching
the Lake Michigan shoreline by mid to late morning Wednesday.

As the comma head precipitation sweeps across the area on Wednesday
in strong cold advection, precipitation will change to snow at
nearly all locations (except maybe the Door Peninsula) by Wednesday
morning. Nearly all locations will have the potential to see 1-2
inches of snow on Wednesday. Most snowfall will diminish in
coverage and intensity by late Wednesday afternoon or evening,
becoming confined to the snowbelt of Vilas County.

Heavy Snow Potential: Thermodynamic profiles look quite favorable
for heavy snow accumulations from late Tuesday night through
about mid-afternoon due to a large dendritic growth layer over
north-central Wisconsin. Lake enhancement looks quite favorable
for Vilas County from Wednesday morning through Wednesday night,
with delta- Ts around 14-17C, favorable wind trajectories, and
equilibrium levels increasing to around 10 kft. The heaviest
synoptic QPF and lake effect will occur in the snowbelt of Vilas
County, where there is a 60-90% chance of 10 inches or more of
snow accumulations. There is a signal (greater than 50% chance) of
snow reaching greater than 20 inches in the far northwest corner
of Vilas County. Consequently, Vilas County was upgraded to a
Winter Storm Warning.

Surrounding areas in Oneida, Forest, and Florence counties are
expected to see snowfall amounts ranging from about 3 to 8 inches,
but uncertainty is higher there due to potential dry slot issues.
Given the strong winds, blowing and drifting snow, and heavy
travel weekend, the Watch was upgraded to a Warning for these
counties as well. Lincoln and Langlade counties were placed in an
Advisory for 3 to 5 inches. Snowfall amounts trail off abruptly
over Menominee, Northern Oconto, and Northern Marinette counties,
so no headlines were issued there for now.

Strong Winds: With strong subsidence in cold advection on the back
side of the low, strong northwest winds are likely to occur late
tonight through Wednesday. Gusts of 40-45 mph appear likely
(50-80% chance) across most of the area. Winds may be slightly
lower in the heavy snow area (30-40 mph). The strong winds
combined with heavy snow will make for very difficult travel over
north-central WI late Tuesday night and Wednesday. Travel could
become impossible in Vilas county if the higher end snowfall
amounts materialize.

Long Term...Thursday through Monday

Strong low pressure will be departing the region over Quebec on
Thursday. Strong cold advection will be ongoing in an amplifying
pattern across North America. Lake effect snow showers will likely
continue into Thursday over north-central WI and perhaps the
northern Door Peninsula, with flurries possible over far northeast
WI outside of these areas. An additional 1-3 inches of snow seems
possible in Vilas County as delta-Ts remain in the mid to upper
teens with favorable wind trajectories. While light snow will
likely continue into Thursday night, dry air finally arrives from
the west over western Lake Superior, which should put an end to
any significant accumulations.

Gusty winds to 35 mph are likely on Thanksgiving Day, making for
a blustery holiday.

An amplifying long wave trough over the center of the continent
will lead to energy crossing the region on Saturday. The system
doesn`t look particularly strong, with an inverted surface trough
accompanying energy aloft. Probabilities indicate a 40-60% chance
of 1 inch or more of snow across central to northeast WI, with
the highest probabilities along the Lake Michigan shoreline. Yet
another system could pass close to the region by early next week.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 506 AM CST Tue Nov 25 2025

A deepening low pressure system will create precipitation
regionwide at times today through Wednesday and poor flying
conditions. A widespread mix of LIFR and IFR conditions are
present across the region early this morning. Some improvement in
conditions is possible during the day today, but IFR/MVFR
visibilities are likely to stick around.

Precipitation is expected to be widespread tonight. Rain will
change over to snow from west to east tonight into Wednesday
morning. A couple inches of snow may accumulate by the end of the
TAF period at Rhinelander. Several inches of accumulations are
likely north of Rhinelander.

Winds will be on increase as well late tonight, but moreso on
Wednesday when gusts are likely to reach up to 35 to 45 mph at
times by mid to late morning.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from 9 PM this evening to 6 AM CST Thursday
for WIZ005.

Winter Storm Warning from midnight tonight to 6 PM CST Wednesday
for WIZ010>012.

Winter Weather Advisory from 3 AM to 6 PM CST Wednesday for
WIZ018-019.
&&

$$

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