641
FXUS63 KGRB 282331
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
631 PM CDT Wed Oct 28 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Showers (60-90%) with a chance of storms (20-40%) this evening
  into early Thursday. Gusty winds to 40 mph and brief heavy
  downpours primary hazards with the storms this evening in north-
  central Wisconsin.

- Additional chances for scattered showers this weekend (10-30%)
  with increasing chances for rain (40-60%) and gusty winds early
  next week, peaking on Election Day.

- Record or near record temperatures this afternoon, with
  temperatures remaining above normal into next week.

- Hazardous conditions for small craft expected tonight into
  Thursday morning. A Small Craft Advisory is in effect for the
  bay and Lake Michigan.

&&

.DISCUSSION...
Issued at 1253 PM CDT Wed Oct 28 2026

Showers and storms tonight...Warm front is lifting north of
Wisconsin. Surface instability is limited to southern Minnesota
on nose of 55-60 surface dewpoints. Surface instability remains
west of central Wisconsin into the evening, even as low-level jet
up 45+ kts arrives ahead of cold front tied to surface low lifting
into western Lake Superior to western Ontario Canada. Showers and
thunderstorms will develop on nose of the LLJ and lift into
central and north-central Wisconsin. Even eastern areas will see
measurable rain, though bulk of QPF (around 0.5 inch) will occur
over north-central Wisconsin. Given strength of winds aloft
(effective shear up to 35 kts) and elevated instability (500+
j/kg), cannot rule out an isolated 50+ mph gust if a line segment
can get going perpendicular to the strong winds aloft, but minimal
surface based instability due to low-level inversion and later
arrival of storms past dark (peak coverage 7 pm to 11 pm), along
with lack of strong forcing and weaker lapse rates seem to point
to weakening convection as it moves in.

We are in a favored portion of larger scale trough for Gravity
Wave Associated Convection (GWAC), but various model reflectivity
fields don`t show the usual look of separated pulses of higher
cores which you sometimes see with GWAC and HREF/REFS data has a
non-existent signal for any higher peak wind gusts. Overall this
setup has a look of brief downpours, gusty winds to 40 mph with
the stronger storms, especially over north-central Wisconsin. SPC
Day1 outlook does clip our north-central, but at this point it
seems like a pretty low-end marginal risk for our area. Rain ends
late tonight into early Thursday as the cold front shifts through.

Dry late this week, then rain chances this weekend...High pressure
settles overhead late Thursday into Friday. Main impact could be
some fog on Thursday night. Coolest temperatures for the next week
will be Thursday night into Friday, but even during the coolest day
readings will still be above normal. Southern stream wave lifts
toward the state on Saturday, but with limited surface reflection
associated rain showers with it will diminish as it moves farther
north. Greatest chances for rain (20-30%) will be over central and
east-central Wisconsin. Thus, could see scattered showers for any
Halloween activities, but not expecting a washout.

Looking ahead, small chances of rain could linger Sunday-Monday,
but better chances continue to ramp up (up to 60%) for Tuesday
which is Election Day. May also see gusty east winds and cooler
temps than current forecast shows especially if stronger surface
low exits the plains to the midwest/Ohio Valley as has occasionally
been shown by models last few days. NBM/LREF probabilities for at
least 0.05 inch of rain on Tuesday continue to be higher.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 623 PM CDT Wed Oct 28 2026

A cold front is expected to move across the area tonight,
bringing a round of showers and scattered storms along with
gusty winds at the surface and aloft. Despite the sun
setting, surface winds will remain gusty to 20 to 25 mph
ahead of the cold front. Aloft, low wind shear will or
has developed early this evening and will continue until
the passage of the cold front. Best chances for thunderstorms
will be at KRHI/KAUW/KCWA TAF sites. Behind the front, there
will be a period of IFR/MVFR CIGS that should last for a few
hours. Fair weather cumulus should develop on Thursday and
could be broken for awhile across the north. Northwest winds
should gust to around 20 knots on Thursday.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......Eckberg