676
FXUS63 KGRB 120547
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1147 PM CST Wed Nov 11 2026

Forecast discussion for routine evening forecast issuance

.KEY MESSAGES...

- Intermittent lake effect snow showers are expected across north-
  central Wisconsin Thursday through Friday night. Accumulations
  have a 30% chance of exceeding 2 inches of snowfall.

- There is a 30% chance lake effect showers also turn inland off
  Lake Michigan into Door and Kewaunee Counties. If this occurs,
  impactful accumulating snow will be possible in these areas
  Friday morning as well.

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

&&

.DISCUSSION...
Issued at 1147 PM CST Wed Nov 11 2026

Lake Effect Showers Across Northern Wisconsin...

Continued cold air advection from the north will bring lake
effect snow showers into the region Thursday through Friday night.
How far inland these showers get throughout the day Thursday and
Friday will vary, but the majority of any accumulations will be
across north- central Vilas County, with only trace to dusting
amounts making their way further inland. Accumulations will be
primarily limited during the day by above freezing surface
temperatures and winds, so although a few inches of snowfall are
in the forecast, actual surface accumulation probabilities are
lower, with around 30% chance of exceeding 2 inches of snowfall
across Vilas County. If snow accumulation proves more robust (10%
worst case), accumulations could get up to 3 to 4 inches over the
course of the 48 hour period.

Lake Effect for Lake Michigan...

Lake effect showers will also be underway over Lake michigan as
the northerly winds increase. The main areas to watch will be Door
and Kewaunee counties, which may see a rapid increase in
precipitation if these showers get enough of an easterly
component to them to bring the banded snowfall onshore. These
areas are also unlikely to see snow mix in until the overnight
period late tonight, with pure snow likely after midnight. That
said, if this band does move inland overnight, impactful snowfall
could be in the works for portions of Door and northern Kewaunee
counties. Lake induced CAPE around 200-300 J/kg, Delta-T around 15
degrees, and good mixing through the lowest layer near the lake
surface would all support concern for a push of higher snow totals
over a relatively localized area, as lake effect snow bands are
typically quite narrow. In the current 10% worst case, this could
bring a faster 4+ inches in 12 hours, which would merit the first
Winter Weather Advisory of the season. Confidence of all this
lining up is increasing over the last couple forecast cycles but
still only sits at around 30% on the probabilistic side, as
p-types over Door do switch back to rain during the latter part of
the day Friday. Therefore, will hold off on any headlines at this
juncture, but where the radar returns over Lake Michigan and the
Bay of Green Bay orient themselves over the next 24 hours will be
important to monitor.

Further Inland...

The rest of the region may see some sprinkles or even flurries at
times, with the flurries more likely during the overnight period
Thursday night into Friday morning as the air column gets colder.
First possible snowflakes region-wide aside, impacts for the rest
of the region will be fairly minimal.

Rest of the Forecast...

Quiet conditions are expected to return to the region over the
weekend. High temperatures that will be near normal Thursday and
Friday will see a slow rise going into next week, getting back
towards the 50s across the region.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1147 PM CST Wed Nov 11 2026

A mix of VFR and MVFR conditions exist across the region to start
the TAF period as lake induced status clouds are expanding
southward across northern WI, while an area of clearing works east
over far northeast and toward east central WI. Cigs may bounce
around for the next few hours over east-central WI before a more
widespread blanket of MVFR status settles  over much of the region
by 8-10Z. The main aviation challenge through the TAF period will be
periods of lake effect rain and show showers coming off both Lake
Superior and Lake Michigan during the day and into Friday morning.
Multiple lake effect bands are expected to set up off Lake Superior
by this afternoon and will periodically impact RHI. There is
uncertainty with how far south into central WI any showers progress
so have limited mentioned of precip at AUW and CWA to PROB30 groups
for now.  For the Lake Michigan shoreline, including MTW, north to
north-northeast winds will likely produce one or two dominate lake
effect bands that may cause periods of MVFR cigs and vsbys, mainly
this afternoon through this evening. For GRB and ATW have left
precip mentions in a PROB30 group as there is some uncertainty if
winds will take on enough of an easterly component to snow flurries
to drift that far in last. Accumulations should be minimal at most
TAF sites with the only about a ~5% chance for greater than 1" at
RHI and around a 10% chance for 1" at MTW.

Winds will remain light early overnight but will increase by the
early morning as strong northerly winds up to 20 to 25 knots
arrive by Thursday morning. A few of these gusts may get up to 30
knots during the day.

&&

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

&&

$$

DISCUSSION.....Uhlmann
AVIATION.......GK

NWS GRB Office Area Forecast Discussion