094
FXUS63 KGRB 110013
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
713 PM CDT Thu Sep 10 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Chances for thunderstorms return on Friday night into Saturday
  morning. The severe weather threat is low.

- Potential for heavy rainfall and thunderstorms increases Monday
  into Tuesday as a stronger low pressure system tracks near the
  region, though forecast uncertainty remains high.

&&

.DISCUSSION...
Issued at 154 PM CDT Thu Sep 10 2026

Mostly clear skies are expected through Friday as high pressure
tracks through the western Great Lakes region.

Storm Chances Return Late Friday: Next chance for
showers/thunderstorms comes late Friday night into Saturday
morning as an upper trough drags a cold front across the region.
The risk for any severe storms is very low (less than 5%) as
forecast soundings show a stout capping inversion during the
period. Guidance also continues to the axis of greatest
instability and moisture remaining well west of the forecast area.
There is still some timing uncertainty with when rain may come to
an end Saturday as recent model guidance has come in slower with
the passage of the front which could lead to showers lingering
through the morning Saturday. Overall the trend with the
rain from this front has diminished from previous runs as some
models suggest the front could pass through with little to no rain
as the best dynamics stay to the north with the best instability
to the south. This is reflected in the latest NBM pops with a
small chance (<10%) across east-central Wisconsin and the
lakeshore. Weak high pressure is then progged to move in
returning dry conditions for the remainder of the weekend.

Heavy Rain and Storms Early Next Week: A dynamic synoptic system
is progged to lift northeast across the northern Plains and
western Great Lakes Monday and Tuesday. Global ensembles show a
strong mass response ahead of this system with PWATS increasing
near 2" which is around 200% of normal for this time of year. The
high moisture content and strong dynamical lift does support an
increased risk for heavy rainfall with NBM probs showing 30-60%
chances greater than 2" of rain across much of the forecast area,
with the highest chances in central Wisconsin. There is also a
low risk for a few stronger storms to develop Monday as strong
~50kt deep layer shear overspreads an unstable airmass; however,
forecast soundings show a stout inversion near the surface which
may keep storms elevated rather than surface based.

Rest of the forecast: There continues to be low chances (20-30%)
for precipitation during the middle of next week as zonal flow
sets up across the Great Lakes. This period could just as easily
be dry as it could be light showers as the models are uncertain
how close a surface boundary will be to the region. If the high
wins out we stay dry, if the boundary is further north we could
see some showers at times. The one thing that seems certain is
that we will be noticeably cooler with highs only in the 60s.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 713 PM CDT Thu Sep 10 2026

VFR conditions will prevail through this TAF period with clear
skies expected tonight and mid and high clouds moving over the
area Friday afternoon and evening. Patchy ground fog may develop
early Friday morning, but confidence that fog impacts any TAF
sites is low.

Light and variable winds are expected tonight. Winds then become
south-southwest Friday, gusting to 15-20 knots with the highest
gusts in north-central WI and over Door County.

Beyond the TAF period the next chance for showers and
thunderstorms arrives with the passage of a cold front late
Friday into Saturday.

&&

.MARINE...
Issued at 154 PM CDT Thu Sep 10 2026

A Small Craft Advisory and Beach Hazards Statement will likely be
needed from Friday afternoon through Saturday morning for gusty
south winds to 30 kts and waves 3-6 ft.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement from Friday afternoon through Saturday
afternoon for WIZ022.

Beach Hazards Statement from Friday afternoon through Saturday
morning for WIZ040-050.
&&

$$

DISCUSSION.....Kurimski
AVIATION.......Kruk
MARINE.........Kurimski