NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 151716
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1116 AM CST Thu Jan 15 2026

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- There is a 60-90% chance for snowfall accumulations greater than
  2 inches across most of the area from this afternoon through
  Saturday. Snow-covered and slippery travel will occur at times.
  Also, there will also be breaks in the steadier snow through
  Saturday.

- Cold temperatures arrive late in the weekend and early next week,
  with wind chills as cold as 10 below to 30 below zero.

- A clipper system may bring light snow and the potential for
  hazardous travel Sunday, and then possibly again during the
  middle of next week.

&&

.DISCUSSION...
Issued at 312 AM CST Thu Jan 15 2026

500mb ridge across western North America will remain firmly in
place during the forecast period, while downstream trough over
eastern North America will result in periodic chances of light
snow along with below normal temperatures during most of the
period. As the upper trough deepens into the weekend, there
will be a prolong period for chances of light snow from this
afternoon through Saturday. As the pieces of energy rotate with
the mean flow of the upper trough, there will be certain periods
of higher chances of light snow, although figuring when and where
can be complicated by each model solution.

For today, skies will vary from mostly clear across central into
portions of northeast WI with mostly cloudy skies across the
north. The next clipper system will spread light snow (60-80%)
into north-central WI between 2 pm and 4 pm, and then across the
rest of the area by early evening in response to 850mb warm
advection. There is scenario across eastern Wisconsin where the
first round of light snow moves across the area through mid
evening, then there will be a break in the snow until later in the
night until main shortwave feature approaches the area. Have
trended lower in the chances of light snow later in the evening
across the east. Also, during the evening, bufkit soundings also
support the potential for freezing drizzle for a few hours across
central into north-central WI. Later tonight into Friday morning,
models depict shortwave energy moving across the forecast area.
There could be a band of steadier snow with lower visibilities
from central WI into the Fox Valley east to the lakeshore, which
could bring a higher impact for the Friday morning commute. There
could be a band of higher snowfall rates and lower visibilities
for a few hours. The chances of light snow continue Friday night
and Saturday as upper trough swings across Wisconsin. The greatest
focus for snow will be across the far north-central WI where snow
chances are 40-80%. The focus for Saturday will be across central
into northeast WI where snow chances are currently 40-70%.
Otherwise, the active pattern will continue with another chance of
light snow on Sunday (30-60%) and possibly during the middle of
next week.

After highs in the 20s to lower 30s on Friday, colder air returns
on Saturday, then temperatures bottom out on Monday. ECMWF
indicated 850mb temperatures of -28C to -30C which supports high
temperatures struggling to warm to around zero. The probability of
highs below 10 degrees were greater than 80%, with near 100% over
north-central WI. The probability of highs not reaching zero
ranged from 10% along the lakeshore to 70% in far north-central
WI. Wind chill readings of -10F to -30F are likely Monday morning
and Tuesday morning, resulting in frostbite on exposed skin in as
little as 20 minutes. Temperatures will moderate towards the
middle of next week, but still below normal. With the warmup will
need to watch for a clipper system thus the potential for some
light snow around the middle of next week.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1116 AM CST Thu Jan 15 2026

VFR conditions will prevail through mid-afternoon as mid and high
clouds increase from the west ahead of an approaching clipper.
Conditions will deteriorate from northwest to southeast late this
afternoon and evening as the atmosphere saturates. Light snow is
expected to reach KAUW, KCWA, and KRHI between 21z and 23z,
spreading to KGRB, KATW, and KMTW after 23z.

Ceilings will drop to MVFR with the initial period of snow late
this afternoon and early this evening, then trend towards MVFR/IFR
overnight as the snow becomes more widespread. Visibilities will
generally range from 1 to 3 miles in snow, with the lowest
conditions expected between 08z and 15z Friday. There is a small
chance for patchy freezing drizzle at KCWA/KAUW late this
afternoon if deeper moisture struggles to reach the ice crystal
growth zone.

South to southwest winds will become gusty tonight with peak
gusts of 15 to 20 kts. Low-level wind shear is also expected to
develop at KRHI, KAUW, and KCWA between 00z and 07z.

Confidence is high regarding the arrival of widespread MVFR
conditions, though low-medium on the exact timing of IFR
ceilings/visibilities in snow.

Outlook...Periods of light snow and MVFR/IFR flight conditions
will continue at times into Saturday.

&&

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

&&

$$

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