NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 272127
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
327 PM CST Sat Dec 27 2025

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- A Winter Storm Warning has been issued for the entire forecast
  area later Sunday into Monday due to heavy snowfall and strong
  winds.

- 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 Sunday night through Monday evening.

- A surge of below normal temperatures is likely towards the New
  Year's time frame. Wind chills as cold as 15 to 25 below zero
  are possible Thursday morning and Friday morning.

&&

.DISCUSSION...
Issued at 325 PM CST Sat Dec 27 2025

Changes with this forecast package: Have upgraded the entire
forecast area to a Winter Storm Warning starting late Sunday and
continuing through Monday, for the potential for heavy snow or a
combination of snow and blowing and drifting snow.

Have also upgraded Gale/Storm Watches to Gale/Storm Warnings from
late Sunday night through Monday evening, with storm force gusts
most likely near Deaths Door.

Sunday PM - Monday Winter Storm Potential:

Confidence now ranging near 80% confidence in winter storm impacts
to warrant issuing a Winter Storm Warning for late Sunday into
Monday.

Temperature Influence:  The temperature profile will be such that
ahead of this system, temperatures will be above freezing in our
area. And on the backside of this low, temperatures notably fall
below freezing... which will cause a rain --> snow transition. The
Winter Storm Warning start times are synced to the progression of
cold air as it spreads from west to east across our area.

Timing:  For the Fox Valley, it will likely not start
snowing/accumulating snow until the 10 pm-midnight timeframe. Expect
most snow to fall in this area at the time surrounding 3 am Monday,
where snowfall rates will likely range from 1 to 2 inches per hour.

For Central Wisconsin into northeast Wisconsin, the transition to
snow should be underway between 4 and 6 pm, with most accumulation
occurring from 9 pm - 3 am.

Total Snowfall:  Models continue to hold QPF amounts of 0.5 to 1
inch across our area. Expecting a foot or more of snow over parts of
Vilas County (aided by lake-effect), 6 to 9 inches across the rest
of northern WI, and 3 to 6 inches across east-cetnral Wisconsin.
This will lead to snow-covered and slippery roadways across most of
our area.

Wind Impacts:  It is very important to note the likelihood of wind
impacts. With an amped up such as this one, accompanying wind gusts
will easily range in the 30 mph to 40 mph during periods of snow. In
northern Door County, wind gusts may reach and exceed 50 mph.

Nearly immediately on the backside of this system as the cold air
takes over and rain transitions to snow, there would be an area of
large dendrites. In conjunction with 30 to 40 mph wind gusts,
visibility would easily fall to 1/2 mile or less. Additionally, with
strong northwest winds gusting to 35 to 50 mph inland, there is
potential for tree damage and power outages.

Cold air arriving middle to late next week...

Confidence increasing in a secondary surge of cold air arriving
behind this system sometime towards the second half of next week. As
of now, minimum wind chill values look to bottom out in the negative
10 to negative 20 degree range, with actual air temperatures
bottoming out in the single digits below zero. So not record-setting
cold by any means, but any outdoor events focused around the New
Year's may be impacted by this cold. With temperatures in this
range, frostbite could occur within 30 to 45 minutes.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 538 AM CST Sat Dec 27 2025

Low stratus (ranging from mostly LIFR to MVFR) will persist
through the TAF period. Fog trends are a bit more problematic, as
models are quite pessimistic about significant improvement in
vsbys. Surface temperatures should remain above freezing in most
areas, so not expecting any significant freezing precipitation
tonight.


&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from 3 PM Sunday to 3 PM CST Monday for
WIZ005.

Winter Storm Warning from 6 PM Sunday to 3 PM CST Monday for
WIZ010-018-030-036.

Winter Storm Warning from 6 PM Sunday to 6 PM CST Monday for
WIZ011>013.

Winter Storm Warning from 9 PM Sunday to 3 PM CST Monday for
WIZ019>021-031-037-038-045-048.

Winter Storm Warning from midnight Sunday night to 6 PM CST
Monday for WIZ022-039-040-049-050-073-074.

Winter Storm Warning from 3 PM Sunday to noon CST Monday for
WIZ035.
&&

$$

DISCUSSION.....Kotenberg
AVIATION.......Kotenberg