290
FXUS63 KGRB 092348
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
548 PM CST Sun Nov 9 2025

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Light lake effect snow showers will continue to impact the snow
  belt of north-central Wisconsin and the Door Peninsula. An inch
  or two of accumulations will be possible through late tonight,
  highest over the northwest part of Vilas County.

- Snow showers, potentially producing low visibility, are possible
  across north-central and central Wisconsin outside of the main
  lake effect belt through early this evening.

&&

.DISCUSSION...
Issued at 247 PM CST Sun Nov 9 2025

A deep and anomalous upper-level trough is digging across the western
Great Lakes this afternoon. This trough, combined with strong high
pressure building in from the Dakotas, has tightened the pressure
gradient across the region, leading to gusty northwest winds to 25
mph. The trough axis will shift east of the area tonight and
Monday, allowing a surface high pressure ridge to build in from
the west by late Monday.

Short Term (This Afternoon - Monday)...

The primary forecast concern revolves around lake effect snow
showers. The most significant impacts were felt over Door County
this morning, where a dominant lake-effect snow band set up and
produced snowfall rates of over one inch per hour from Ephraim to
Jacksonport. However, a slight backing of the low-level winds has
since pushed this main band east of the peninsula. Renewed
banding over the county has been disorganized and cellular, likely
disrupted by daytime instability. With some dry air expected to
work in from the northeast late this afternoon, robust
reorganization of the band is not expected. Therefore, the Winter
Storm Warning for Door County has been canceled.

Across north-central Wisconsin, lake effect snow showers intensified
around midday, particularly over Vilas County, though
accumulations have generally underperformed so far. Scattered snow
showers continue to develop across the western half of the forecast
area this afternoon. While instability remains present, organized
snow squalls are not expected, and the Winter Weather Advisory for
Oneida County has also been canceled.

As the upper trough shifts east tonight, lake effect parameters will
become less favorable. Low-level winds will waffle between north
and northwest, and rising mid-level heights and temperatures will
lessen instability. Still, additional accumulations of 1 to 2
inches will be possible over northern Vilas County through Monday
morning. Door County will continue to see scattered snow showers,
though dry air and shifting wind directions will limit additional
accumulations to an inch or less tonight.

For Monday, the surface ridge axis moves in from the west. This
will bring diminishing snow showers over the north and increasing
sunshine across the area by the afternoon. Highs are expected to be
in the 30s.

Long Term (Monday Night - Saturday)...

Flattened troughing will remain aloft over the region through
Thursday. A brief wave of light warm advection snow is possible
late Monday night into Tuesday morning, which could result in a
dusting to perhaps a half-inch of snow, mainly over central and
north-central Wisconsin. Another weak impulse could bring
additional light snow into far northern Wisconsin late Tuesday
night into Wednesday. Following this, gusty northwest winds are
likely on Wednesday, with gusts potentially exceeding 30 mph.

Otherwise, the weather looks quiet for the latter half of the work
week. Upper-level ridging is forecast to slowly build in from the
west, allowing temperatures to moderate by the end of the week.

The next chance for precipitation appears to be next weekend.
Models show a developing trough ejecting from the west, which
could bring a system with rain and wind into the area.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 545 PM CST Sun Nov 9 2025

Scattered snow showers or flurries will gradually diminish
and end tonight, except across the far north where snow will
linger into Monday morning. Any additional accumulation of snow
will be across the north and over Door County. Most sites will see
VFR conditions, although MVFR CIGS and possibly IFR conditions in
the heavier snow showers. Gusty northerly winds will diminish
tonight, but then pick back up late Monday morning and continue
Monday afternoon. Winds will quickly subside towards 00z on
Tuesday.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 AM CST Monday for WIZ005.
&&

$$

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