224
FXUS63 KGRB 131130
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
530 AM CST Fri Nov 13 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Intermittent lake effect snow showers are expected across north-
  central Wisconsin through this afternoon. There is a 50% chance
  for another inch of snow in Vilas County.

- Watching the potential for a very localized, but heavier band of
  snow to potentially develop over the Door Peninsula tonight.
  Probability to see 4" or more of snow sits at 20%.

- Mainly dry this weekend with a slow warming trend into early
  next week.

&&

.DISCUSSION...
Issued at 1212 AM CST Fri Nov 13 2026

Departing upper trough will bring another day of cooler and
cloudy conditions, with on and off lake-effect potential. Quiet
weather will follow this weekend into next week.

Snow across northern Wisconsin...Little change in the forecast
across north- central WI, as this setup has remained fairly
similar. Typical cooler air over warmer water is generating lake-
effect snow bands which occasionally stretch into northern
Wisconsin. In a lull at the moment, but expect additional develop
tonight as lift in the low-levels increase. Once again
accumulations will remain limited to far north-central WI (Vilas
County) where another inch or so (20-50% chance for 1" or more)
could accumulate tonight. Potential for more than 2" is around
10-20%. After ~14Z the lift is lost, and CAMs also feature less
snow getting into northern WI, so expect a steady downward trend
throughout Friday afternoon, with any remaining snow showers or
flakes winding down by Friday evening.

Snow across Door/Kewaunee counties...Questions regarding whether
a lake-induced precip band make it onshore tonight remain. A band
started to develop a little after 00Z, which appeared to be mostly
rain reaching the ground. If there were any snowflakes, they
melted upon contact with the ground. This band has since
dissipated with more unorganized development now taking place over
central Lake Michigan. Soundings still show favorable conditions
in general for effective snow production tonight, with some low
level instability and lift. The HRRR continues to be the most
aggressive with painting a narrow, heavier snow band of 4+ inches
in parts of Door and Kewaunee counties near Lake Michigan. Other
guidance is far less enthused. Probabilities for at least 1" are
as high as 60%, and as high as 20% for 4" in a very localized
area. A negating factor is the surface and ground/road
temperatures, which are expected to be just above freezing all
night. If an intense band makes it onshore this could overcome the
temperatures, but otherwise expect lighter snow would mostly melt
with accumulations limited to cold and grassy surfaces. Will be
monitoring the lake precip overnight and make forecast adjustments
as necessary.

Elsewhere...Some flurries could occur across northern or eastern
Wisconsin tonight, otherwise dry weather is expected.

Rest of the forecast...Upper ridging and surface high pressure
start to take over by Sunday, leading to sunnier skies and a
gradual warming trend with highs mostly in the 50s next week. The
next opportunity for rain could arrive Thu or Fri as we transition
to southwest flow, but a lot of inconsistency that far out.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 529 AM CST Fri Nov 13 2026

Lake induced status will continue to stream off Lake Superior and
northern Lake Michigan today creating a mix of MVFR and VFR
conditions across the area through most of the TAF period. Light
snow is falling out of these clouds across far north-central WI as
indicated by surface obs across Vilas. These snow showers may at
times impact RHI this morning with cigs/vsbys becoming MVFR,
however, those impacts should be fairly brief as the lake bands off
Lake Superior are struggling to hold together that far inland. A
lake effect snow band has also been falling over Door and Kewaunee
counties early this morning, however, over the past few hours this
band has started to fall part and drift off-shore. There is a chance
the band becomes reorganized this morning along the shoreline,
however, given these recent trends think impacts at GRB and MTW
should be fairly minimal through the TAF period, with only brief
periods of MVFR cigs expected early this morning at MTW.

North winds will be steady around 5 to 10 knots with occasional
gusts of 15 to 20 knots through this afternoon with winds
decreasing this evening.

&&

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

&&

$$

DISCUSSION.....KLJ
AVIATION.......GK

NWS GRB Office Area Forecast Discussion