337
FXUS63 KGRB 011811
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1211 PM CST Mon Dec 1 2025

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- Light snow will move across the area this afternoon and evening.
  Accumulations of a half inch to an inch are expected, which
  could lead to scattered slippery stretches on roadways for the
  evening commute.

- An arctic front will bring another chance of light snow Tuesday
  night into Wednesday, followed by the coldest air of the season so
  far.

- Hazardous wind chills of 10 to 20 below zero are forecast for
  Thursday morning west of the Lake Michigan shoreline.

&&

.DISCUSSION...
Issued at 227 AM CST Mon Dec 1 2025

Short Term...Today...Tonight...and Tuesday

The latest RAP analysis and satellite/radar imagery show mid-level
height rises taking place across the western Great Lakes between
shortwave energy over the eastern Great Lakes and energy over the
northern Plains to the Rockies. Broad warm advection is taking
place across the central Plains with high clouds streaming into
Iowa and southern Minnesota. Over Wisconsin, a large area of
clouds remains stubborn over the northwest half of the state
associated with thermal troughing at 850mb. Within that cloud
mass, scattered flurries are occurring, which has held up
temperatures in the Northwoods early this morning. As the various
shortwaves move across the Plains and into the center of the
country, light snow chances are the focus of the forecast through
tonight.

Precipitation Chances: Shortwave energy currently over the Northern
Plains will dig southeast into the northern Mississippi Valley this
afternoon and the western Great Lakes tonight. Moisture from the
central Plains will stream northeast ahead of the shortwave over the
course of the day. With the mid and high clouds moving overhead, it
is difficult to envision the low stratus mixing out over north-
central WI, so a mention of flurries was kept through the morning
hours.

With deepening saturation, a chance of light snow will move into
central WI in the early to mid afternoon hours, before proceeding
northeast into northeast WI from mid to late afternoon. It appears
central to northeast WI will have a 6 to 9 hour window for light
snow. Forecast soundings indicate ascent looks rather weak and
located above the dendritic growth zone. Therefore, anticipate lower
snow ratios than initialized with the NBM and minor accumulations,
perhaps a half inch to an inch by the end of this evening, highest
over east-central WI. Scattered slippery spots could develop on
roads, particularly for the evening commute, but it should not
cause significant impacts. Most of the light snow activity should
taper off or exit east by late tonight.

Cloud Trends and Temperatures: Confidence is rather low regarding
how long low clouds will stick around after the snow ends late
tonight into Tuesday morning. Current thinking is that low clouds
will hold tough into Tuesday over north-central WI, but northeast
parts of the state could see some clearing. High temperatures
today will range from the mid teens to lower 20s. Similar highs
are expected Tuesday, ranging from the lower  to middle 20s.

Long Term...Tuesday Night Through Sunday

The main focus of the long term forecast revolves around the passage
of an arctic front mid-week, bringing accumulating light snow followed
by the coldest airmass of the season.

Snow Chances Tuesday Night/Wednesday: Additional shortwave energy
moving across central Canada and the northern Plains will push an
arctic front across the region late Tuesday night into Wednesday. A
period of deep saturation along the front will bring the next chance
of light snow to the region. Snow chances generally range from 30 to
50 percent. QPF values have been increased slightly based on
numerical model output rather than the national blend of models to
account for the forcing. Most areas could see a half inch of
accumulation, but isolated amounts up to 1 inch will be possible.

Temperatures and Wind Chills: Behind this arctic front, the coldest
air of the season will arrive. High temperatures on Thursday will
struggle to reach the single digits and lower teens. Lows below zero
are expected on Wednesday night away from the immediate
lakeshore. Combined with steady west to northwest winds, wind
chills are forecast to range from 10 below to 20 below zero
Wednesday night into Thursday morning west of the lakeshore and
bayshore.

Extended Outlook: Temperatures will moderate slightly heading into
the weekend, returning to the 20s. Additional light snow chances
will arrive from Thursday night through the weekend as clipper-type
systems traverse the flow. Confidence regarding significant or
impactful snow remains low during this period, though some guidance
produces a relatively stronger system for next weekend.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1211 PM CST Mon Dec 1 2025

Primarily MVFR flying conditions area wide early this afternoon
with BKN-OVC clouds between 1-3kft. Light snow will spread into
central and east-central WI early to mid-afternoon, and then
depart this evening. Occasional ceiling and visibility drops
within the snow will bring IFR conditions at times, otherwise
MVFR will remain. Improvements to VFR are expected across east-
central and northeast WI late night as sky partially clears and
cloud bases rise. MVFR/IFR flying conditions are likely to persist
in central and north-central WI through the TAF period as low
clouds hang tight.

SW winds will gust to around 15kts in northern WI early this
afternoon, otherwise winds will be light (less than 10 kts) from
the W/SW through the TAF period.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

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