377
FXUS63 KGRB 281757
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1257 PM CDT Wed Oct 28 2026

Forecast discussion for routine afternoon forecast 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 18Z TAF Issuance
Issued at 1253 PM CDT Wed Oct 28 2026

Warm front is north of area and low clouds have scattered out. VFR
clouds with a brief period of showers are expected at CWA/AUW/RHI
this afternoon. As cold front and low-level jet move in this evening,
plan on at least a few hour period of showers with embedded storms.
Greatest risk for isolated strong storm with wind gusts over 40 kts
will be at RHI. Started to hint at these gusty winds in the TAF
there. Otherwise, have used mix of TEMPO and PROB30 groups at the
other TAF sites to cover the potential for storms. All rain should
exit eastern WI sites after 08z-09z Thursday.

Flight conditions will be VFR this afternoon, then deteriorate to
low end VFR and MVFR tonight as the showers shift through. MVFR
clouds may linger into mid morning for most sites, before the
clouds scatter out late morning into the afternoon. A few pesky
MVFR to VFR stratocu could hang on well into the afternoon north
of RHI.

Regarding winds, gusty southerly winds this afternoon will
persist through tonight, before winds shift to the northwest on
Thursday morning behind the cold front. Gusts up to 20 kts could
continue on Thursday. Low-level wind shear (LLWS) down to 015 AGL
occurs tonight as the low-level jet is directly overhead, only
abating from north to south 06z-11z Thursday.

&&

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

&&

$$

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

NWS GRB Office Area Forecast Discussion