468
FXUS63 KGRB 182333
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
533 PM CST Sun Jan 18 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Widespread light, powdery snowfall expected through late
  tonight. Up to 1 inch for most, with up to 3 inches in Vilas
  County. Strong gusty winds of 30-45 mph to follow the snowfall,
  resulting in blowing and drifting snow late tonight through
  Monday morning.

- Winter Weather Advisories issued for Vilas County due to lake
  effect snow and blowing and drifting snow, and for Door County
  due to blowing and drifting snow off the Bay of Green Bay.
  Whiteout conditions are possible at times across Door County.

- Cold Weather Advisory in effect from late tonight through midday
  Monday, with additional cold weather headlines likely into
  Tuesday.

&&

.DISCUSSION...
Issued at 457 PM CST Sun Jan 18 2026

Snowfall through Monday...

This afternoon`s radar and surface observations showed light snow
moving across the forecast area from west to east in association
with a mid-level shortwave overhead. The light snowfall will
continue to track across the region through late tonight,
lingering the longest into Monday morning across far north-
central WI due to lake enhancement. Snowfall amounts will mainly
be under one inch, with the exception of Vilas County, where up
to 3 inches is expected. However, as colder air moves into the
area later tonight with the arrival of an arctic front, the DGZ
will lower to the surface, causing SLRs to lower as well,
resulting in the snow to be more of a sand-like consistency. This
consistency is not ideal for higher snow accumulations, but is
efficient at reducing visibility when paired with stronger winds,
which arrive later tonight.

Gusty winds Causing Blowing Snow...

Following the aforementioned shortwave, an arctic front will move
across the region, providing a strong push of CAA. This will allow
for a 30-45 kt LLJ to mix to the surface. These northwest wind
gusts will increase mainly after midnight and continue through
midday Monday. The strongest winds up to 45 mph are anticipated
along the lakeshore, including Door County, around daybreak Monday
through mid-morning Monday. The combination of the recently fallen
snow and the strong winds will raise concern for blowing and
drifting snow across the region. The greatest confidence for
impacts from the blowing and drifting snow is over Door County, as
there is an added nudger of the light snow sitting on the frozen
Bay of Green Bay that will blow east across Door County.
Maintained the Winter Weather Advisory for Door County for this
reason, but depending on how conditions appear upstream this
evening/late tonight, additional Winter Weather Advisories may
need to be issued for portions of central and east-central WI,
where there are more open areas (compared to locations across the
Northwoods--more trees). Regardless, there is still potential for
impacts to the Monday morning commute across the entire region.
Winds will gradually decrease through Monday afternoon/evening.

Bitter Cold Wind Chills...

The arctic front will bring a rush of colder air across the
region by Monday morning, causing low temperatures tonight to drop
to the single digits above and below zero. The addition of the
strong northwest winds will result in bitter cold wind chills as
low as 20 to 30 below zero late tonight through midday Monday. A
Cold Weather Advisory remains in effect for the entire region,
except Door County, until noon Monday. However, there appears to
be little recovery during Monday afternoon before wind chills drop
to Cold Weather Advisory criteria again. For now, kept the end
time of noon Monday, but could see it being extended through
Tuesday morning, as wind chills will be in the advisory criteria
range again. That being said, high temperatures on Monday will be
well below normal with values ranging from just below zero to the
single digits above zero.

Rest of the week...

Active winter weather persists. A clipper system with more
QPF/snow expected for the region Tuesday night into Wednesday.
Current indications have more snowfall over southern WI, but this
system has been bouncing back and forth. More snow could occur
late this week ahead of a very sharp mid-level trough dropping
across the western Great Lakes. ECMWF is very frigid, compared to
what occurs early this week, showing a 850mb temp over northern WI
of -37C! Note there is a lot of spread among the guidance due to
timing issues, but will continue to monitor how this evolves.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 533 PM CST Sun Jan 18 2026

A mix of VFR and MVFR CIGs prevailed across the region late this
afternoon as another round of light snow was tracking through the
region. This light snow will generate MVFR cigs and MVFR/IFR
VSBYs as it marches across the region, exiting late this evening.
However, lake-effect snow showers will persist in north-central
Wisconsin through midday Monday, which will keep MVFR cigs at the
KRHI TAF site.

As the snow ends late this evening, strong northwest winds will
develop mainly after 06z Mon, as high as 30-35 kts. These winds
will generate blowing and drifting snow with vsbys potentially
dropping to IFR. The blowing and drifting snow impacts will
likely continue through Monday morning mainly for the east-
central WI TAF sites as winds remain higher there the longest.
Winds to gradually subside during Monday afternoon and evening
with the potential for some clearing on Monday.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 9 AM CST Monday for WIZ005.

Cold Weather Advisory from 3 AM to noon CST Monday for WIZ005-
010>013-018>021-030-031-035>040-045-048>050-073-074.

Winter Weather Advisory from 3 AM to noon CST Monday for WIZ022.
&&

$$

DISCUSSION.....Kruk
AVIATION.......Kurimski

NWS GRB Office Area Forecast Discussion