281
FXUS63 KGRB 221449
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
849 AM CST Mon Dec 22 2025

New Information added to update section

.UPDATE...
Issued at 849 AM CST Mon Dec 22 2025

Radar returns show a narrow area of heavy snow/freezing rain has
lifted north of the Fox Valley and is currently stretching from
just north of Shawano to Sturgeon Bay. Under the highest returns
obs sites have been primarily reporting snow with a brief period
of freezing rain trailing just behind the snow. This may cause
some roads to become slippery over far northeast WI over the next
hour to two. Over central WI there light snow continues to fall
out of a low status deck. Upstream obs are showing the ceilings
rising quickly and warming cloud tops along the I-94 corridor
which should bring an end to the snow over the next hour to two in
central WI.

Roads may continue to be slippery for a few hours after
precipitation comes to an end, however, with warming temperatures
today should see improving travel conditions for this afternoon.

&&

.KEY MESSAGES...

- Light snow to spread north this morning, resulting in a band of
  1 to 2" accumulations centered on the Hwy 29 corridor. Freezing
  drizzle may mix in at times, resulting in slippery travel during
  the morning and evening commutes.

- Above normal temperatures are expected through the work week,
  with highs expected to read above freezing.

&&

.DISCUSSION...
Issued at 154 AM CST Mon Dec 22 2025

Precip chances... Radar returns show light snow over southeast
Minnesota early this morning coincident with the nose of a
developing LLJ and right-rear quad of an upper jet. Snow should
make it to central Wisconsin within the next few hours, spreading
north and east throughout the morning before reaching the Hwy 29
corridor by the Monday morning commute. Pockets of moderate
snowfall (0.5 to 0.75"/hr) will be possible as top-down saturation
occurs, resulting in potential for hazardous/slippery conditions
during travel time. Upper shortwave looks to be fairly weak and
transient, so suspect that amounts within the main band of precip
will total between 1 and 2 inches, locally higher in areas of
focused mid-level FGEN. CAMs latch onto a signal for some
freezing rain mixing in as winds take on a more southerly
component and a push of WAA warms the near-surface layer, though
remain pessimistic in this sense. Warm nose looks to be extremely
shallow, only reaching +1 or 2 degrees. Dry air also begins to
work its way into the column by late morning, so suspect that
freezing drizzle would be the more likely scenario. This being
said, any freezing precip falling on top of fresh snow may create
some slippery spots on roads. In addition, new CAM development
shows a secondary round of freezing drizzle developing from west
to east later this evening and overnight across our southern two
tiers of counties due to isentropic lift along the leading edge of
stronger WAA. Low-level lift thus increases, though any
precipitation processes look to remain below 5k ft where better
saturation is. Have hand-drawn in PoPs accordingly.

Ensemble cluster analysis shows a signal for more widespread
precip arriving toward the end of the week, though there are still
significant timing/location issues within the synoptic pattern.
This being said, p-type issues would likely arise as warmer air
dominates most of the CONUS. Will continue to monitor in the
coming days, especially with potential impacts to post-holiday
travel in question.

Temperatures... Consistent signal for above average temperatures
over at least the next week as height rises and periods of
southerly flow usher in a +20C anomalous airmass at 850 mb. Highs
will read above freezing for most through the end of the work
week, with some locations across central Wisconsin and the Fox
Valley even flirting with 40 degrees. Above freezing dewpoints
will accompany the warmer air, which, when paired with the
possibility of rain, could result in the development of widespread
fog/low clouds on Christmas.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 524 AM CST Mon Dec 22 2025

Stratus deck will continue to thicken as light snow arrives from
the southwest early this morning. Cigs will eventually lower to
low-end MVFR/IFR by late morning as snow spreads northeast, with
vsby reductions to IFR possible within areas of moderate snowfall.
A swath of 1 to 2-inch accumulations will be possible from a GRB
to CWA line, with the potential for freezing drizzle to mix in at
times. A second round of freezing drizzle then arrives later in
the afternoon, resulting in a prolonged period of at least MVFR
stratus.

LLWS concerns come to an end by the beginning of the TAF period as
850 mb winds subside. Otherwise, surface winds back to
southeasterly this afternoon, gusting between 15 and 20 knots.

&&

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

&&

$$

UPDATE.........GK
DISCUSSION.....Goodin
AVIATION.......Goodin

NWS GRB Office Area Forecast Discussion