818
FXUS63 KGRB 221712
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1112 AM CST Sat Nov 22 2025

Updated aviation portion for 18Z TAF issuance

.UPDATE...
Issued at 1042 AM CST Sat Nov 22 2025

Couple reports of light snow and/or graupel in northern WI and
also over portions of central WI as warm air advection precip,
with touch of mid-level instability, shifts across the region ahead
of cold front. Added/expanded small mention of light rain/snow or
sprinkles/flurries next few hours. Main area of concern from this
precip impact wise would be over northern WI if ptype falls as
rain (as it did upstream at IWD) as road temps in far northern WI
are still just below freezing. Precip intensity is very light, so
this should minimize the issue. No other changes of note to going
forecast.

&&

.KEY MESSAGES...

- Mild with no significant precipitation expected until late
  Monday afternoon or evening.

- A pattern change is expected in the middle of next week, with
  colder and blustery conditions, along with possible gale force
  gusts on the bay and lake. Some snow accumulation possible over
  northern Wisconsin Wednesday into Thursday.

&&

.DISCUSSION...
Issued at 326 AM CST Sat Nov 22 2025

Mid-level clouds were spreading into the forecast area as WAA
increased ahead of a cold front approaching from the eastern
Dakotas. In advance of the clouds, clear skies and light winds
allowed temperatures to drop into the teens and 20s.

WAA, mid-level FGEN and a weak short-wave trough may generate
enough saturation for patchy light mixed snow/rain near the
WI/Upper MI border today. The previously-mentioned weak cold
front will move through the region this afternoon/evening. High
pressure builds back into the region by Sunday, and lingers into
Monday morning. Although clouds will hold back temperatures a bit
today, abundant sunshine on Sunday should allow the typical warm
spots to reach 50 degrees.

Rest of the forecast: The remnants of a Southwest U.S. upper low
will lift northeast toward the Great Lakes, bringing a chance of
light rain to our western counties Monday afternoon, and
widespread light to moderate rain to the entire region Monday
night into Tuesday. A strong upper trough over the Northern
Plains will then shift northeast and close off into an upper low
as it moves through northern WI/Upper Michigan Tuesday night into
Wednesday. This system will bring a mix of rain/snow Tuesday
night, which should change to mainly snow on Wednesday. As the
system shifts northeast Wednesday night into Thursday, gusty
northwest winds should bring potential for lake-effect snow to
the Lake Superior snowbelt, including Vilas County. Accumulating
snow will be possible across northern Wisconsin during this
period, with the highest likelihood of significant amounts
occurring over Vilas County. Due to the strength of the system,
there is increasing potential for northwest gales on Lake
Michigan Wednesday into Thursday.

Minor lake-effect may continue into Friday over the far north, but
Saturday is looking mainly dry at this point.

Temperatures: Normal to above normal temperatures are expected
through Tuesday, with much below normal readings likely for the
mid to late part of next week.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1111 AM CST Sat Nov 22 2025

Cold front moves through this evening, switching winds to northwest
(gusts to around 20 kts at times) and bringing in LLWS from west
to east. The LLWS will persist into Sunday morning for all but
MTW, where it will end late tonight. Plan on a VFR altostratus
deck with a few sprinkles/flurries (no expected impact to the
terminals) into early this afternoon, giving way to scattered mid
and high clouds late this afternoon through the rest of the TAF
period.

&&

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

&&

$$

UPDATE.........JLA
DISCUSSION.....Kieckbusch
AVIATION.......JLA