NWS-Green Bay Forecast Discussion
FXUS63 KGRB 290137
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
737 PM CST Sun Dec 28 2025
New Information added to update section
.UPDATE...
Issued at 737 PM CST Sun Dec 28 2025
RAP analysis shows the surface low is now moving over western MI
as it continues to deepen. Within the TROWL region across far
northeast and east-central WI wet heavy snow is falling, except
right along Lake Michigan where a mix of snow and rain is still
being reported. Further west a a dry slot has brought a lull in
the snowfall to areas along the I-39 corridor in central WI. Dry
slot may cut into snow totals across central WI a bit. However,
snow should begin to pick back up over the next hour to two as a
cold front currently draped across far NW WI swings across the
region. Snow ratios with this round of snow will be much higher
than the initial round so hesitant to cut down on totals too much.
Behind the front surface obs are showing wind gusts of 30-40 mph
around and west of the Twin Cities. These stronger gusts will
arriving into central and northern WI around midnight which will
result in increasing blowing and drifting snow. North of HWY 8
moderate to heavy snow continues as winds veer around to the north
northwest allowing for some lake enhancement. The higher end
totals of 9-15" across Vilas county and 8-12" north of a
Rhinelander to Iron Mountain line still seem realistic.
&&
.KEY MESSAGES...
- Winter Storm Warnings are in effect for the entire forecast
area, for heavy snow, strong winds and considerable blowing and
drifting snow, from through Monday. Treacherous travel
conditions are likely, and some tree damage and power outages
are possible.
- Strong northwest winds gusting to 35 to 50 mph inland, and gale
or storm force gusts to 45 to 50 knots on Lake Michigan, are
anticipated from late tonight through Monday evening.
- A surge of below normal temperatures is likely towards the New
Year's time frame. Wind chills as cold as 10 to 20 below zero
are possible Thursday morning and Friday morning.
&&
.DISCUSSION...
Issued at 259 PM CST Sun Dec 28 2025
Changes to Winter Storm Warning Headlines: Have upgraded Door
County to a blizzard warning. Confidence in wind gusts reaching and
briefly exceeding 50 mph in Door County, especially the northern
portion of Door County, is high enough to support prolonged
visibility of less than 1/4 of a mile during periods of snow.
We would also like to highlight the potential for power outages with
this winter storm, especially in northern Door County, and
northern/north-central Wisconsin. Held off for now on upgrading to a
Blizzard Warning across our northern counties due to the
topography... In short, across the heavily forested area of the
Northern Highlands, it is especially difficult to achieve
prolonged blizzard conditions. Though snowfall amounts will be very
high (nearing 1 foot) across that portion of the state, there is not
enough confidence that visibility will remain below 1/4 of a mile
for a prolonged enough period of time.
Otherwise, have held headline timing for Winter Storm Warning as-is,
and snowfall amounts have remained largely unchanged over the past
24 hours. (A good reminder to focus on impacts versus focusing
solely on snowfall amounts. The impacts of 4.53231 inches of snow
will be about the exact same as the impacts of 5.334341 inches of
snow. So focus on impacts with this system- which are the snow-
covered and slippery roadways, plus the potential for power outages
due to snow and winds downing tree branches onto power lines)
Snowfall timing: Overall, timing of this event remains on track,
with a transition from rain to snow occurring across our area from
west to east. The transition should begin in central Wisconsin
between 4 and 6 pm, spreading westward until it reaches the Fox
Valley region between 10pm and midnight or so. Most of the
accumulating snow will taper off late tonight into late Monday
morning. The Monday morning commute will likely be impacted by
winter storm conditions.
Snowfall amounts: Again, remain largely unchanged from the past 24
hours. Expecting 10 to 16 inches of snow over parts of Vilas County
(aided by lake-effect), 6 to 10 inches across the rest of northern
WI, and 4 to 7 inches farther south into east-central Wisconsin.
Wind impacts: Strong winds gusting to 35 to 50 mph will produce
considerable blowing and drifting snow, and high-end gale to storm
force gusts are likely on Lake Michigan. The strongest winds will be
across northern Wisconsin and especially Door County and Washington
Island. The combination of heavy snow accumulations and winds will
likely cause some tree damage and power outages, most notably over
northern WI and Door County. Winds are not expected to decrease
much until later in the day or evening, so blowing and drifting snow
will likely continue.
A clipper system passes north of the region Tuesday afternoon and
night, bringing a chance of snow followed by a surge of arctic air
for the New Year. As of now, confidence is high that total snowfall
amounts will be around 1 inch or less... leading to nil or very
minimal impacts.
Behind this clipper system, confidence remains high for wind chill
values to fall to the negative 10 to negative 20 degree range later
in the work week.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 507 PM CST Sun Dec 28 2025
A potent winter storm is creating poor flying conditions across the
region this evening. Moderate to heavy snow will continue to impact
central and northern tonight with vsbys dropping to 1/4-1SM within
the heaviest snow showers. Further east rain will linger for another
few hours before transitioning to snow. Rain showers are creating
MVFR vsbys, but this will fall to IFR with the transition to snow.
Cigs also remain IFR/LIFR across much of the region, however, there
may be brief periods where the low status scattered out and cigs
become MVFR.
Tonight winds will strengthen as they veer around to the northwest.
Gusts of 30-40KTs are expected overnight into Monday morning. The
strong winds will create areas of blowing and drifting snow. Even as
snowfall comes to an end Monday morning visibilities impacts may
linger into the early afternoon due to blowing snow. A push of drier
air and downsloping winds should help to scatter out the low clouds
Monday afternoon across central and east-central WI, however, lake
induced MVFR status is expected to linger at RHI through the TAF
period.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 3 PM CST Monday for WIZ005-011>013-
038-039-048-049-073-074.
Winter Storm Warning until noon CST Monday for WIZ010-018>021-
030-031-035>037-045.
Blizzard Warning from midnight tonight to 9 AM CST Monday for
WIZ022.
Winter Storm Warning from 9 AM to 6 PM CST Monday for WIZ022.
Winter Storm Warning from midnight tonight to 6 PM CST Monday
for WIZ040-050.
&&
$$
UPDATE.........GK
DISCUSSION.....Kotenberg
AVIATION.......GK