743
FXUS63 KGRB 040010
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
710 PM CDT Thu Sep 3 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- A round of strong to severe storms is expected to move across
  northern and central WI tonight, between 10PM and 6AM. Main
  hazard will be damaging wind gusts along with heavy downpours.

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

&&

.DISCUSSION...
Issued at 117 PM CDT Thu Sep 3 2026

Rest of Today through Friday: This mornings convection has largely
pushed east of the region. There are a few clusters of
showers/storms redeveloping over western WI, just east of the Twin
Cities along a nearly stationary warm front. These storms may drift
north and east into central and northern WI this afternoon, but with
limited instability and fairly weak upper level flow don`t expect
mush storm organization keeping the severe risk low through the
afternoon.

The severe storm risk does increase late this evening and overnight
(4-11Z) as an MCS, currently tracking into far northwest MN, moves
east across the forecast area. CAMs are coming into decent agreement
that this MCS will track along a warm front/instability gradient
draped across northern MN and into north-central WI. Primary hazard
will be damaging wind gusts 50-60mph along with periods of heavy
rain. One aspect that remains uncertain is how far east the severe
wind risk will persist overnight as instability will be waning which
may result this system becoming elevated above a stable boundary
layer. One factor does does point to some storm maintains is an
increasing LLJ nosing into north-central WI resulting in locally
enhanced low-level shear. CAMs generally show convection exiting the
area to the east early Friday morning leaving the rest of the day
mostly dry. There are some hints that a few isolated showers/storms
could develop Friday afternoon during peak heating as a weak
shortwave moves across the region, however, the risk for stronger
storms expected moreso over southern where instability is expected
to be greater.

This Weekend into Next Week: Warm and humid summertime air mass will
continue to dominate the region through this weekend. While much of
the weekend should be dry, there will be periodic chances for shower
and storms with any weak short-waves that pass over the region.
Given the subtle nature of the forcing confidence in the timing an
location of any storms this weekend is low. Beyond this weekend
there is a 50-60% chance for showers/storms next Tuesday and
Wednesday with a cold frontal passage.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 710 PM CDT Thu Sep 3 2026

Scattered clusters of showers with embedded thunderstorms are
expected to continue this evening into tonight, producing a mix
of VFR, MVFR, and IFR conditions. The majority of the activity
will exit by 15z Friday. The strongest storms could produce gusty
winds, small hail, and heavy rain. A period of low ceilings and
fog (mainly IFR/MVFR) are expected Friday morning behind the area
of showers/storms, but a few spots could see LIFR conditions for
a time. Conditions slowly improve later Friday morning into Friday
afternoon as ceilings lift.

&&

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

&&

$$

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

NWS GRB Office Area Forecast Discussion