606
FXUS63 KGRB 130041
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
641 PM CST Thu Nov 12 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Periods of lake effect snow showers across north-central
  Wisconsin and rain/snow showers along Lake Michigan with
  20-40 percent chances for at least 2 inches through Friday.

- Although any wet accumulating snowfall will be confined to
  narrower corridors across north-central Wisconsin or possibly
  along Lake Michigan, motorists should be prepared for wintry
  driving conditions, especially given the early season nature
  of the snow.

- Dry weather this weekend into next week with high confidence
  (80-90%) for temperatures gradually rebounding above average.

&&

.DISCUSSION...
Issued at 1225 PM CST Thu Nov 12 2026

Lake effect rain/snow showers through Friday:

A deep upper low will persist over the Great Lakes late this
week keeping the area in cyclonic flow aloft and cool, northerly
flow. The 12Z sounding from KGRB indicated deep northerly flow
throughout the profile with cold advection throughout the lower
atmosphere. This regime will result in areas of low clouds and
lake effect rain/snow showers into Friday. Reports of around an
inch of snow have been received this morning across Vilas
County.

Lake effect snow showers will continue intermittently across parts
of north-central Wisconsin into Friday with around 20 to 40 percent
chances of at least 2 additional inches of snow.

Across the western shore of Lake Michigan, some wet snow
accumulations may also occur across Door or Kewaunee Counties,
mainly overnight into Friday morning, as the low level temperature
profiles cool to support mainly snow. With primarily northerly flow
in the low levels, there is some uncertainty in whether and to what
extent any bands become established onshore. As a result, confidence
remains low (~20%) for accumulations of at least 2 inches. We`ll be
monitoring trends closely heading into tonight. With the warmer
ground and air temps hovering near freezing, any accumulation would
be more likely on grassy/cold surfaces in the absence of heavier
bands. However, motorists are urged to monitor conditions,
especially if traveling along lakeshore areas, and practice winter
driving conditions in areas of snow showers, especially being early
in the winter season.

Warming, mostly dry this weekend into next week:

Surface ridging will work east across the Great Lakes over the
weekend into early next week as mid level heights build across the
central US. Confidence is high for an extended period of mainly dry
weather. In addition, temperatures will trend back above
average into next week as warm advection develops behind the
departing high. Temperatures are expected into the 50s for much
of the area by the middle of next week, even as average daytime
highs continue to fall through the 40s. The next chances for
precipitation will hold off until at least late next week when
the overall flow pattern is forecast to become southwesterly and
moisture spreads northward.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 641 PM CST Thu Nov 12 2026

A mix of MVFR/VFR flying conditions this evening as sct-bkn
stratocu clouds around 2500ft move across the area. Light snow is
noted from these clouds at times across far north-central WI, and
current radar showing some lake enhanced precip starting to
develop over the Door Peninsula, currently falling as rain based
on radar and surface obs.

Will continue to see flying conditions bounce between MVFR and
VFR, especially across north-central WI and far northeast WI as
lower clouds go BKN at times. Elsewhere, prevailing VFR
conditions expected through the TAF period with cigs around 5kft.

Main concern to watch is lake effect show showers possibly
impacting KRHI at times, but confidence in vsby drops or category
change impacts from this snow is too low to include in TAFs. Snow
will be light and very intermittent. While a lake snow band may
develop of the Door Peninsula tonight, likelihood of this
impacting KGRB or KMTW is too low to include in TAFs as well.

North winds will be steady around 5 to 10 knots with occasional
gusts of 15 to 20 knots through the TAF period.
SCT030 OVC040.

&&

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

&&

$$

DISCUSSION.....JM
AVIATION.......KLJ

NWS GRB Office Area Forecast Discussion