223
FXUS63 KGRB 041140
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
640 AM CDT Fri Sep 4 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Scattered thunderstorms will end by mid-morning. Some of the
  storms could contain large hail and damaging winds. Torrential
  rainfall with rates of 1-2" per hour could lead to localized
  flooding.

- Isolated thunderstorms are possible again later this afternoon
  and early this evening. If storms develop, they could become
  strong or severe with damaging winds and large hail.

- Dry conditions prevail this weekend, then periodic rain/storm
  chances expected the first half of next week. Above normal
  temperatures to continue.

&&

.DISCUSSION...
Issued at 242 AM CDT Fri Sep 4 2026

Scattered thunderstorms continue to move across the area early
this morning. There have been scattered reports of strong
winds/wind damage or large hail with the storms across east-
central WI. Meanwhile, still watching a line of thunderstorms
entering northwest WI as of 2:30 am. Still some uncertainty
on how far east these storms will make it into northeast WI
later this morning. Otherwise, storms should come to an end
by mid-morning.

Otherwise, skies will become partly cloudy with warm and humid
conditions this afternoon. The combination of the heat and
humidity is expected to trigger isolated thunderstorms late
this afternoon into early this evening. Still plenty of
instability and shear that may cause some of the storms to
become strong or severe with damaging winds and large hail.

Dry conditions are expected this weekend, then the chances of
thunderstorms arrive late Monday and continue into Tuesday
night as a cold front moves across the area. Stronger storms
are possible Tuesday and Tuesday night. Above normal temperatures
will continue into the middle of next week with highs in the
middle 70s to middle 80s. Dry conditions expected Wednesday
and Thursday as high pressure moves across the region.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 632 AM CDT Fri Sep 4 2026

Scattered showers and thunderstorms will exit northeast WI
by 15z this morning. Otherwise areas of MVFR/IFR CIGS should rise
into the VFR category this afternoon. Later this afternoon into
early this evening, isolated thunderstorms are possible across
the region. Coverage and confidence in storms at the TAF site
is very low, thus did not them to the 12z TAFS. The bigger story
for tonight will the low clouds and fog that will develop
during the late evening and overnight hours. Conditions may  be
at airport minimums at the TAF sites. It will take to about
15z to clear the fog on Saturday with gradually improving
CIGS by early afternoon.

&&

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

&&

$$

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

NWS GRB Office Area Forecast Discussion