NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 141130
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
630 AM CDT Sat Mar 14 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- A major winter storm will impact the region tonight through
  Monday. Heavy snow, mixed precip, and strong winds will create
  near blizzard conditions as well as widespread and significant
  impacts across the area, including extremely difficult travel
  and power outages. Winter Storm Warnings have been issued.

- Sleet and/or freezing rain will likely mix with snow at times
  across east-central Wisconsin, resulting in the potential for
  0.1 to 0.2" of ice accumulation on Sunday. Precip then
  transitions back to all snow Sunday night.

- Below zero wind chills will be possible on Monday, moderating
  back to near normal throughout the week.

&&

.DISCUSSION...
Issued at 156 AM CDT Sat Mar 14 2026

Significant winter storm this weekend... Par for the course,
focus continues to revolve around a long-duration and potentially
record-setting snowfall event lasting tonight through Monday. A
potent Colorado low is on track to approach the Great Lakes at or
near absolute min relative to climo, continuing to deepen along
its trek. Isentropically-forced precip will thus begin late
Saturday night within WAA regime, before the main precip
shield/deformation band sets up over northeast Wisconsin on
Sunday. Combination of dynamic forcing and ample moisture
transport from an open Gulf will result in a high likelihood for
at least 1 inch/hour snowfall rates, with periods of 2 or even 3
inch/hour rates possible within the main FGEN band on Sunday. As
such, there is no reason to believe that we won't see record-
setting snowfall amounts somewhere over northeast Wisconsin during
this event. However, the northward trend of the low track and
intrusion of low-level warm air across our southern tier of
counties will continue to be a hindrance to the forecast as p-type
issues arise. Several CAMs try to pick up on a warm nose from
central Wisconsin to the southern Fox Valley, resulting in
potential for periods of sleet and/or freezing rain cutting into
overall snow amounts. All things being relative, there remains a
strong signal (50 to 80%) for receiving at least 18 inches of snow
over these areas, mixed p-types notwithstanding. Additionally,
much colder air wrapping around the back side of the low would
quickly erode at the shallow warm layer. Thus, areas generally
south of Hwy 29 would still be approaching record-setting
territory. However, better potential for record snowfall exists
mainly north of Hwy 29, where localized amounts up to 30 inches
will be possible (60 to 90%).

Winds... Winds ramp up out of the northeast on Sunday as the
pressure gradient tightens up along the departing low. Gusts to 45
mph will be possible during this time, especially as decent mixing
taps into near 60 knot winds at 850 mb. When combined with high
snowfall rates, blizzard or near-blizzard conditions will be
possible, especially Sunday afternoon into Monday. Gales will
likewise be possible in our marine zones.

Headline considerations... Main consideration on this shift was
whether or not to upgrade portions of the Winter Storm Warning to
a Blizzard Warning. While confidence remains high that blizzard
conditions will be met somewhere across the forecast area, there
is still some uncertainty about where conditions will align best
and where the lowest visibilities will be, especially in more
heavily forested areas across the Northwoods. Have opted to hold
off on issuing a Blizzard Warning for the time being, though this
will need to be considered later on. Regardless of the headline,
it is to be emphasized that widespread and significant impacts
will accompany this storm, including dangerous travel and power
outages.

Extended... Northwesterly flow regime will result in a period of
below normal temperatures early next week, including below zero
wind chills on Monday. Highs then slowly moderate back to near
normal, and even above normal, throughout the work week.
Otherwise, transient shortwave energy dives over the Great Lakes
mid-week, resulting in the possibility of picking up another
couple inches of snow. No significant impacts are currently
expected.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 624 AM CDT Sat Mar 14 2026

Mid clouds will continue to lower and thicken throughout the day
as low pressure approaches from the southwest, eventually becoming
MVFR or IFR by late this evening. Light to moderate snow will
accompany the lowering cigs, spreading north and increasing in
intensity overnight. Vsbys will likely lower into LIFR territory
within the heavy snow. Freezing rain or sleet will likely mix with
the snow at times across the east-central Wisconsin terminals,
resulting in the potential for icing. A widespread 12 to 18 inches
of snowfall is likely through Monday, with locally higher amounts
possible. As a result, air travel will be impacted across the
region, including the potential for airport closures.

Winds increase out of the northeast late Sunday morning, gusting
between 30 and 40 knots at most terminals. When combined with
heavy snow, blizzard or near blizzard conditions will be possible,
resulting in potentially prolonged periods of quarter mile or less
vsbys.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from 1 AM Sunday to 4 PM CDT Monday for
WIZ005-010>013-021-073.

Winter Storm Warning from 7 PM this evening to 4 PM CDT Monday
for WIZ018>020-022-030-031-035>040-045-048>050-074.
&&

$$

DISCUSSION.....Goodin
AVIATION.......Goodin