159
FXUS63 KGRB 301112
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
512 AM CST Sun Nov 30 2025

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Additional snow accumulations up to an inch or two are possible
  this morning. Expect snow covered and slippery roads to impact
  travel.

- Hazardous travel conditions will likely persist into this
  afternoon over eastern Wisconsin. While the snow will end this
  morning, northwest winds gusting to 25 to 35 mph will cause some
  blowing and drifting snow, especially in open areas and on east-
  west oriented roads.

- Much colder air will arrive for the start of next week. Wind
  chills may fall to 10 below zero or colder Monday morning.
  Another surge of arctic air is expected Wednesday night,
  bringing widespread wind chills of 10 below to 20 below zero.

&&

.DISCUSSION...
Issued at 330 AM CST Sun Nov 30 2025

The latest RAP analysis shows potent shortwave energy crossing from
the Upper Mississippi Valley into the western Great Lakes early this
morning. At the surface, low pressure is currently crossing southern
Lake Michigan and will track northeast across the thumb of Lower
Michigan into Lake Huron and Quebec later today. This system is
driving widespread precipitation across eastern Wisconsin within the
comma head of the cyclone. Several embedded banded features remain
evident on area radars pushing inland from Lake Michigan, likely
producing an additional 1 to 2 inches of accumulation across eastern
Wisconsin before the snow diminishes later this morning. Meanwhile,
snow intensity is comparatively lighter over far north-central
Wisconsin where visibilities generally range between 2 and 5 miles.
As this system departs, a winter-like pattern will establish itself
across North America for the upcoming week, characterized by ridging
off the West Coast and broad troughing extending from Hudson Bay into
the Great Lakes.

Snow, Blowing Snow, and Gusty Winds Today:

The primary forecast concern for the immediate short term
revolves around the remaining snowfall accumulations and the
impacts from gusty winds and blowing snow. The current Winter
Storm Warning and Winter Weather Advisory will be allowed to
expire at 6 AM as planned. However, as the widespread synoptic
precipitation tapers off by mid-morning, the pressure gradient
will tighten significantly on the backside of the departing low.
Northwest winds are expected to increase just as the falling snow
diminishes, with gusts of 30 to 35 mph possible. These gusty winds
will be most prevalent from the Fox Valley to the lakeshore,
coinciding with areas receiving the heaviest snow this morning.
Consequently, blowing and drifting snow is likely, particularly in
open areas and on east-west oriented roads. Given the high volume
of traffic expected for the post-holiday weekend, a Winter
Weather Advisory for blowing snow has been issued until 3 PM today
for the area stretching from southern Marinette County down to
Winnebago County and eastward to the lake. Conditions should
improve by late afternoon as winds gradually subside. It is noted
that while synoptic snow ends, light lake effect snow showers will
likely persist over Vilas County into the afternoon, and flurries
may linger elsewhere through midday.

Temperature Trends and Wind Chills:

As the low departs, high pressure will build into the region tonight,
leading to clearing skies. The combination of fresh snow cover,
clearing skies, and lightening winds will create conditions for
radiational cooling, allowing temperatures to tank, particularly
in the typical cold spots of north-central Wisconsin. Temperatures
have been manually adjusted lower by several degrees in these
locations to account for this. Overnight lows will support wind
chill values dropping as low as 5 below to 10 below zero across
the Northwoods by early Monday morning. After a brief moderation
on Monday and Tuesday, a potent arctic front is forecast to cross
the region Tuesday night. Behind this front, 850mb temperatures
plummet, ushering in the coldest air of the season thus far. Low
temperatures are forecast to fall below zero at many locations
on Wednesday night. This will likely result in widespread
hazardous wind chills ranging from 10 below to 20 below zero
across much of the forecast area early Thursday morning.

Upcoming Light Snow Chances

The active winter pattern will keep chances for light precipitation
in the forecast through the week at times, though impacts look low.
Clouds will return on Monday with a small chance of light snow
moving into parts of central and northeast Wisconsin during the
afternoon and evening as a weak system moves across the region.
This system continues to trend northward in recent model guidance.
Snow chances have risen to around 40 percent, highest over east-
central Wisconsin, but moisture is limited. Any accumulations
generally look to be minor, perhaps a dusting, and significant
travel impacts are not currently expected. A more widespread
chance for snow (40-60 percent) arrives late Tuesday night into
Wednesday associated with the passage of the arctic front. While
coverage may be broader, moisture availability will again limit
accumulation potential, with amounts likely remaining relatively
light and generally not exceeding one inch. Light snow will remain
possible at times late in the week as cyclonic flow persists over
the Great Lakes.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 512 AM CST Sun Nov 30 2025

As low pressure exits the region to the east, conditions will
slowly improve today. Snow will gradually taper off from west to
east this morning, except north of RHI where lake- effect snow
showers should linger into the afternoon. Behind the system,
gusty north to northwest winds could produce some localized
blowing and drifting of the new snow that could reduce
visibilities below 6SM at times. Winds should gradually subside
this afternoon. Conditions should improve to VFR at most
locations during the afternoon as ceilings rise or break up.

High pressure builds into the region tonight. Some guidance
generates fog over central WI overnight, but confidence is low
and refrained from adding it to the forecast.

Plowing operations will be needed at all airport sites.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 AM CST early this morning for
WIZ005-010>013-018-019-021.

Winter Storm Warning until 6 AM CST early this morning for
WIZ020-022-030-031-035>040-045-048>050-073-074.

Winter Weather Advisory until 3 PM CST this afternoon for WIZ022-
038>040-048>050-073-074.
&&

$$

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