NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 312358
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
558 PM CST Wed Dec 31 2025

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Bitterly cold air following an Arctic front will cause wind
  chills to drop between 15 below and 25 below zero late tonight
  through the morning of New Years Day.

- A fast moving clipper system is likely (60% chance) to bring a
  dusting to a few tenths of an inch of snow on New Years Day,
  especially across central and east-central Wisconsin.

- Intermittent chances for light, fluffy snow through the weekend
  and into early next week as fast-moving clipper systems
  traverse the region.

&&

.DISCUSSION...
Issued at 207 PM CST Wed Dec 31 2025

An Arctic front has swept through the region earlier today,
ushering in colder temperatures and gusty northwest winds across
the area. Although the heaviest snow has ended, some light snow
showers and flurries continue in the wake of the front across
northeast, east-central, and central Wisconsin. Further north,
lake effect snow showers continue across the lake effect snowbelt
region. The snow across much of the region should end late this
afternoon into early this evening with the loss of daytime
heating, with the lake effect across the far north tapering off
this evening. Additional snowfall amounts should be de minimis,
with a few tenths of an inch of additional snowfall possible
across the far north.

Clouds should clear out tonight as high pressure builds in across
the upper Mississippi Valley, which will allow a precipitous drop
in temperatures tonight. Lows are expected to tumble into the
single digits below zero across central and north-central
Wisconsin, with around zero expected across east-central
Wisconsin. Although winds will ease some tonight, winds will still
be 10 to 15 mph for much of the overnight hours. The cold
temperatures and winds will push wind chill values down to around
20 below across central and north-central Wisconsin, with middle
teens below zero across east-central and northeast Wisconsin.
While these will be cold wind chills to ring in the new year, they
will fall just short of Cold Weather Advisory criteria.
Therefore, no headlines are anticipated for the cold wind chills
tonight into New Years Day.

A fast moving clipper system will track through the area on New
Years Day. Although the moisture from this system is fairly
meager, there is weak frontogenesis in the Dendritic Growth Zone
(DGZ) and snow ratios are in the upper teens to near 20:1. As
these earlier clipper systems have demonstrated, it doesn't take
much moisture and lift to produce measurable snow with high snow
ratios and if the lift is in the DGZ. Therefore, will raise POPs
across central and east-central Wisconsin to likely (60% chance)
during the afternoon on New Years Day as this system tracks
through the region. Snowfall amounts should generally be a
dusting; however, around a half of an inch of snow is possible.

Beyond New Years Day, the upper level pattern remains relatively
stable with fast-moving clipper energy generating periodic light
snow. This stable northwest flow will support additional clippers
on Saturday, again late Sunday into Sunday night, and again on
Tuesday. Each of these systems carries a 30 to 50 percent chance
of producing a half inch or more of light, fluffy snow.
Temperatures will remain below normal through the weekend before
beginning to moderate during the early to middle part of next
week.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 554 PM CST Wed Dec 31 2025

Lake effect clouds and flurries with conditions as low as MVFR
(mainly from cigs) will linger from north-central to central WI
(RHI, AUW, CWA) through this evening before clouds scatter out
later. Other sites will see mostly clear skies through the night.
Mid clouds increase by daybreak on Thursday ahead of yet another
clipper system with light snow. The snow will cross the region
between 16z and 22z with MVFR cigs and vsby as low as IFR. Steady
snow diminishes to scattered flurries by Thursday evening.

&&

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

&&

$$

DISCUSSION.....Kurimski
AVIATION.......JLA