929
FXUS63 KGRB 110455
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1055 PM CST Wed Dec 10 2025

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- There is a 40 to 60 percent chance of light snow on Friday.
  While any accumulations generally should be under an inch, a
  light coating of snow may result in locally slick travel.

- A period of hazardous cold air will impact the area Friday
  night through the weekend with wind chills of 15 to 30 below
  zero likely at times, lowest over central Wisconsin.

- Temperatures will begin to trend back towards mid-December
  averages by the middle of next week.

&&

.DISCUSSION...
Issued at 145 PM CST Wed Dec 10 2025

Tonight-Friday: Cold, Light Snow Friday

Low-level stratus remained prevalent along with some flurries this
afternoon as colder air continues to work across the region. Broad
troughing will remain anchored across the eastern US through Friday
keeping our area in cold northwest flow aloft. Although colder air
arrives for the weekend, the next few days will still be well below
average with highs in the teens and 20s and lows mainly in the
single digits on either side of zero, modulated by cloud trends.
Snow with a shortwave trough dropping southeast from the northern
plains on Thursday will largely skirt southwest of the area, but
some flurries or light snow may graze central Wisconsin on
Thursday.

There is higher confidence for light snow on Friday with synoptic
forcing ahead of the push of Arctic Air. NBM snow chances have
increased into the 40 to 70% range on Friday, while raw global
ensemble probabilities are in the 60 to 90% range. Precipitation
chances often are underdone with very light precip events, such as
this. Although probabilities for an inch of snow are generally
low (<25%) outside of perhaps far north-central Wisconsin with
some influence from Lake Superior, soundings show a deep dendritic
growth zone ahead of the dry, Arctic airmass, so a light, fluffy
coating of snow may occur on Friday.

Saturday-Sunday: Hazardous Cold

The most significant hazards and impacts through the next week will
be related to a bitterly cold airmass impacting the region for a
relatively short period of time over the weekend. Synoptically, a
deep upper trough will settle over the Great Lakes through the
weekend while strong Arctic high pressure builds south across the
plains. The low-level thermal fields will crash behind the Arctic
front with strong-level cold advection and gusty winds Friday
night, while some low-level cold advection and wind persist into
the weekend with the ridge axis passing to the west. The core of
the coldest air will settle over the region on Saturday with 925
mb temperature percentiles in the 1-5th percentiles relative to
climo along with a very dry, Canadian airmass. Probabilities for
wind chills lower than 25 below zero are in the 50-80% range
Friday night, lowest across central Wisconsin while probabilities
only decrease into the 50% range across central Wisconsin during
the day on Saturday. Although winds may be a bit lighter on
Saturday night, it will remain bitterly cold with the higher
chances (40-80%) for wind chills at least 25 below zero across
central Wisconsin. Cloud trends may impact temperatures, but
regardless, very cold air will impact the region this weekend.

It is likely that cold weather headlines will be needed for portions
of the area for some time periods Friday night through Sunday, with
central Wisconsin likely to be coldest.

Monday-Wednesday: Rebounding Temps

This bout of cold weather will be short-lived as warm advection
kicks in on the backside of the high. A more zonal flow pattern will
develop through the work week ushering in a milder Pacific airmass.
Although there continues to be notable spread in temps, the trend
points towards more seasonable temps by the middle of next week.
There is a signal for a mid-week trough/frontal passage, but no
significant precipitation is expected through the first half of
next week at this time.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1046 PM CST Wed Dec 10 2025

Low clouds were slowly departing central WI, but were spreading
back into NC/NE WI late this evening. Will only carry MVFR
ceilings at the RHI TAF site for now, but this will need to be
monitored, as the clouds were not showing any signs of eroding as
they pushed south. Will keep the low ceilings in at RHI until
late morning. Otherwise, the rest of the forecast area will see a
gradual increase in high/mid clouds across the area Thursday
afternoon and evening.

Northwest winds 5 to 10 kts are expected tonight, and these should
become light and variable by late Wednesday afternoon and evening.

&&

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

&&

$$

DISCUSSION.....JM
AVIATION.......Kieckbusch