Green Bay, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

486
FXUS63 KGRB 230005
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
605 PM CST Mon Dec 22 2025

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- There is a chance (25-40%) of light drizzle or freezing drizzle
  late this evening across mainly eastern WI. Untreated roads may
  become slippery, depending on road temperatures.

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

- Confidence is increasing for a round of mixed wintry precipitation
  late Thursday evening into Friday. Travel impacts will be possible.

&&

.DISCUSSION...
Issued at 208 PM CST Mon Dec 22 2025

Another surge of WAA and the nose of a subtle LLJ will bring another
round of light wintry precipitation parts of central and eastern WI
this evening. With the mid-level WAA a more pronounced warm noise is
expected to develop this afternoon and evening likely leaving
freezing rain/drizzle as the main p-type this evening. Overall QPF
amounts are expected to be light, maybe a hundreths or two, however,
event those light QPF amounts could cause a glaze of ice on untreated
surfaces. Pinning down where exactly ice accumulations will occur
still remains a challenge as near surface temperatures will likely
hover right around freeze across central and east-central WI this
evening. Any one traveling this evening should be alert for slippery
road conditions and allow extra time to reach you destination.

Dry conditions should return to the region Tuesday as a ridge builds
over the central CONUS. The majority of ensemble global ensemble
members show a weak short-wave coming across souther WI Wednesday
evening which could spur on some rain showers from the Fox Valley to
the lakeshore. With thermal profiles warming during this time think
any freezing precipitation is unlikely.

500mb cluster analysis continues to show a wide range of possible
scenarios for a system arriving late on Christmas Day evening,
however, a signal for a messy mixed precipitation event has been
persistent now in the ensemble guidance for several forecast cycles.
Thermal profiles are most favorable for freezing rain north of a
Marshfield to Green Bay line. NBM probs show a 25% chance for at
least a glaze of ice north of this line late Thursday into Friday
morning. Impacts from this system may be exacerbated due to
increased post-holiday travel. Still a lot of details to work out
with this system, but if you plan to be on the road Thursday evening
or Friday morning keep up to date with the latest forecast
information and adjust travel plans as needed.

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 00Z TAF Issuance
Issued at 602 PM CST Mon Dec 22 2025

VFR early this evening with cigs 040-060. Some concern that
patchy light drizzle over southern WI will eventually reach into
east-central WI late this evening into the early overnight hours
with cigs lowering to MVFR. Continued to carry PROB30 groups for
drizzle/freezing drizzle at GRB/ATW/MTW. Have removed the mention
at AUW/CWA. Based on current trends upstream, there is lower
confidence in this precipitation moving into much of our area.
Behind this possible precipitation, expect cigs to lower as IFR-
MVFR stratus develops over the region. Periods of LIFR status are
possible late tonight into Tuesday morning, mainly for AUW, CWA,
and RHI. Gradual improvements in flying conditions are expected
late Tuesday morning though Tuesday afternoon.

&&

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

&&

$$

DISCUSSION.....GK
AVIATION.......JLA