NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 021142
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
642 AM CDT Wed Sep 2 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Severe thunderstorm watch in effect until 6 AM for Portage,
  Waupaca, Waushara, Winnebago and Wood counties.

- Round of thunderstorms expected this morning, especially across
  central and east-central WI. Some of the stronger storms may
  produce damaging winds and up to 1" hail.

- Another round of thunderstorms are possible again late Wednesday
  night and Thursday. This complex of thunderstorms could become
  strong or severe. There is a Marginal (Level 1) or Slight (Level
  2) risk of severe storms south of a Merrill to Manitowoc line.

- Above normal temperatures and periodic rain/storm chances will
  continue into the weekend.

&&

.DISCUSSION...
Issued at 229 AM CDT Wed Sep 2 2026

Scattered thunderstorms developed across Winnebago, Calumet and
Manitowoc counties early this morning in response to 850mb
warm advection. Some of the stronger storms could produce small
hail, especially across Waushara County through 3 am. Meanwhile,
additional convection was noted across west-central WI with
complex of severe thunderstorms across southeast Minnesota where
a gust to 59 knots was recorded. This complex of storms is
expected to move into central WI by 5 am. Some of the storms could
produce strong/damaging winds and hail up to one inch in diameter.

The showers and storms come to an end later this morning with dry
conditions expected this afternoon. A break in the storms is
expected Wednesday evening, with the next round of storms expected
late Wednesday night and Thursday. Timing and location hard to
pinpoint between the differing model solutions. The latest NAM
has trended southward which seems reasonable with the best
instability to our south. The Storm Prediction Center Day 2
Severe Storm Outlook has a Marginal (Level 1 of 5) or Slight
(Level 2 of 5) south of a Merill to Manitowoc line. From Friday
through the weekend, there are periodic chances of thunderstorms
while above normal temperatures continue into next week.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 636 AM CDT Wed Sep 2 2026

Scattered showers and thunderstorms will exit northeast
WI by 15z. Fair weather cumulus will develop around 15z
between 2,500 and 4,000 feet and rise to 5-6 thousand
feet late this afternoon. Patchy fog expected late tonight due
to the combination of light winds and clear to partly cloudy
skies. Fair weather cumulus redevelop on Thursday.

&&

.FIRE WEATHER...
Issued at 229 AM CDT Wed Sep 2 2026

Not as warm or dry across the north compared to Tuesday. Highs
across the north should climb into the upper 70s to lower 80s
with minimum relative humidity values between 45 and 55 percent.
Unfortunately, the far north is likely to miss out on the rain
this morning. However, there are periodic chances of thunderstorms
from late Wednesday night through the weekend. Hopefully one of
the rounds of storms will bring some much needed rain.
Moisture from prior rainfall should keep fuels from reaching
critical thresholds. Looking forward, extreme drought continues to
expand over portions of northwest Wisconsin. Will continue to
monitor fire weather conditions throughout the month, especially
after we get our first frost/freeze.

&&

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

&&

$$

DISCUSSION.....Eckberg
AVIATION.......Eckberg
FIRE WEATHER...Bersch/Eckberg