294
FXUS63 KGRB 240456
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1056 PM CST Sun Nov 23 2025

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- Mild (highs in the 40s and 50s) through mid-week, with a
  pattern change to colder and wetter weather to follow.

- Accumulating snow is likely over northern Wisconsin late Tuesday
  night into Thursday, with locally heavy snow possible in Vilas
  County. Winter weather headlines will likely be needed.

&&

.DISCUSSION...
Issued at 135 PM CST Sun Nov 23 2025

This afternoon... GOES water vapor imagery shows a corridor of
low-level moisture riding an upper ridge this afternoon,
resulting in expansion of mid clouds across northeast Wisconsin.
As such, temperatures have read several degrees below forecast
highs due to ineffective surface heating. Push of WAA will result
in clouds continuing to lower and thicken across the north
overnight, with slightly more mild lows expected as such.

Rain/snow chances... Forecast concerns continue to revolve around
potential for travel impacts on Wednesday as a dynamic system
remains on track to bring wintry weather to much of the Great
Lakes. First leg of the system will come in the form of widespread
light to moderate rain Monday afternoon through Tuesday as a
cutoff low residing over the Southwest US rejoins the mean flow,
ejecting into the upper Mississippi Valley. Should be at least a
semi-wetting rainfall on the order of 0.25 to 0.5" through
Tuesday, which will prove beneficial given prolonged drought
conditions. Rain then transitions over to snow late Tuesday night
into Wednesday as cyclonic flow turns northwesterly, ushering in a
slew of CAA. This is where additional forecast complications
arise as potential for mesoscale banding within lake enhancement
regime comes into play. Further uncertainty lies in a phasing
scenario, where the southwest cutoff low interacts/merges with a
northern stream shortwave that rides the US/Canada border.
Regardless, suspect that there will be a very tight gradient in
snowfall amounts across the Lake Superior snowbelts in the far
north, with probabilistic guidance showing a signal (50 to 70%
chance) for 8+" in northern Vilas. Trowal airstream looks to
remain just off to our north, though any southward nudge would
bring higher amounts further south. At this point in time, main
concern would be a localized FGEN band setting up somewhere over
north-central Wisconsin, which would put us well within winter
storm criteria were it to materialize. As such, will continue to
monitor the need for winter weather headlines in the next day or
two. Worth mentioning is the fact that winds ramp up during this
time as the pressure gradient tightens, introducing the
possibility for blowing and drifting snow during holiday travel.
As it pertains to marine hazards, NBM probs currently show a 30 to
50% chance of reaching gale force gusts on Lake Michigan
Wednesday into Thursday.

Any remnant lake effect should come to an end on Friday as
Canadian high pressure takes over the upper Midwest, affording us
a brief dry spell. Inverted surface trough then brings another
round of light snow to northeast Wisconsin over the weekend as we
undergo a pattern change to colder, wetter weather.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1056 PM CST Sun Nov 23 2025

Quiet conditions are expected for most of the overnight period,
but winds will be on the increase aloft Monday morning, which
could produce a brief period of LLWS across the area before winds
mix to the surface.

High clouds are on their way into the region for the overnight
period but no impacts are expected on ceilings until MOnday
afternoon as rain approaches our area. Expect ceilings to fall
steadily into the MVFR to IFR by Monday evening as widespread rain
showers cross the region. The rain will likely also reduce
visibility at times across the region.

&&

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

&&

$$

DISCUSSION.....Goodin
AVIATION.......Uhlmann