435
FXUS63 KGRB 171150
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
550 AM CST Mon Nov 17 2025

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Light snow tonight into Tuesday morning across the south with
  accumulations less than 1 inch, but monitoring for a narrow
  heavier band. The Tuesday morning commute could be impacted,
  mainly along Hwy 10.

- Another weather maker brings precip chances (30-60%) Thursday,
  mainly in the form of rain.

- Temperatures remain pretty seasonal through the week.

&&

.DISCUSSION...
Issued at 327 AM CST Mon Nov 17 2025

Precip Chances: Dry conditions will continue across the area today
as high pressure slowly drifts east of the region. Then attention
turns to the approaching compact, shortwave trough and FGEN moving
from the Plains into the southern Great Lakes. The northern trend
of the models have come to a halt, with a slight nudge back to the
south. More hi-res guidance is now being utilized with this
system, and models are in decent agreement with the FGEN band
(with consensus keeping the heaviest band just to our south or
just clipping the southern row of counties). However, still some
finer details to iron out regarding how far north the band will
get and if any heavier snowfall totals can be realized. REFS/HREF
probabilities of 0.1"+ of snow remain between 0-40% south of Hwy
29 (highest south) with a sharp northern edge, with 1.0"+ at
0-30%, highest just west of the Fox Valley toward Waushara/Wood
counties. DGZ and best lift will be quite high (around 15,000 ft)
for much of the event, but a secondary lower area of lift does try
to form Tuesday morning (with the best FGEN in the 800-600mb
range). Temp profiles will be nearly isothermal, so any minor
change could lead to a little mixed precip, but it is looking
like mainly snow will fall on the northern side of the precip/FGEN
band. With any lighter precip on Tuesday ending as some rain.
Expecting a tight precip gradient as drier air will be advecting
in from the east/northeast, with QPF possibly ranging from zero to
around 0.2-0.3" within one county, but again, just where that
will eventually set up is still a little fuzzy. Snow plumes in
central WI (WI Rapids) are clustered under an inch (mean of 0.5")
with still a few higher members (highest around 4.5") which likely
accounts for the FGEN band being further north.

Have slowed the arrival slightly (dry air to overcome) and
tightened up the precip gradient with this forecast, keeping
accumulations mainly south of a Marshfield to Appleton line and
really focused the highest QPF/precip along Hwy 10, where we will
have up to 1" of snow. Where/if the heavier snow band makes it
into the area, the snow will on the wetter side, with SLR`s under
10:1 with snow rates of a half inch per hour. Any wobbles in the
FGEN snow band will need to be monitored as we could end up
staying almost completely dry or have a 1-4" snow band sneak into
the southern row of counties.

Dry conditions will prevail on Wednesday as high pressure drifts
over the Great Lakes. Next chance (40-70%) for precip arrives
Thursday as a clipper-like system races across southern Canada.
While the best moisture and dynamics will be north of the area,
some WAA, a shortwave trough, along with a weak frontal
boundary, will move across the area to produce some precip.
Amounts are looking on the light side, with probabilities of
0.25"+ under 25%. Looking like mainly rain, but a little snow
could mix in over the north. Ensembles have really backed off on
bringing a more moisture rich, wrapped-up system for Friday into
Saturday, so unfortunately prospects for any substantial rain now
looks low.

Temperatures & Winds: Temps will remain pretty close to normal for
the first half of the week, with highs mainly in the upper 30s to
mid 40s and lows in the upper teens and 20s (slightly warmer near
Lake Michigan). A brief shot WAA will give a small bump in temps
on Thursday with highs in the mid and upper 40s for most
locations. We could get a 50 in the south, but probabilities of
reaching 50 remain under 20% due to cloud cover. Winds will be
much lighter today and for the majority of the week, with gusts
only reaching up to 15 mph.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 549 AM CST Mon Nov 17 2025

VFR conditions are expected today into tonight with light winds
and some high clouds drifting across the region at times. Lower
clouds and some flurries will be approaching ATW by ~12z Tuesday
as the next weather maker approaches. This system will bring light
snow (possibly mixed with a little rain) to portions of central
and east-central WI Tuesday morning, especially along and south of
Hwy 10, after 10z.

&&

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

&&

$$

DISCUSSION.....Bersch
AVIATION.......Bersch