162
FXUS63 KGRB 041925
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
225 PM CDT Fri Sep 4 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Very low chance (less than 25%) of isolated thunderstorms late
  this afternoon into this evening. If storms develop, they could
  become strong with strong winds and hail.

- Fog is expected to develop overnight. Patchy dense fog is
  possible.

- Dry conditions for Labor Day weekend. Rain/storm chances return
  late Monday through midweek.

&&

.DISCUSSION...
Issued at 225 PM CDT Fri Sep 4 2026

Today through tonight...Dry conditions prevailed across the area
this afternoon under an area of low clouds. Most areas are expected
to remain dry through this forecast period, but, some models are
showing signs of an area of weak convergence developing across the
central portion of the state late this afternoon into this evening
that may generate isolated showers and storms. Forecast soundings
indicate a decent cap over the area, so unless some ascent can occur
from the weak convergence, the forecast area will remain dry.
However, if the storms develop, they may become strong capable of
producing strong, wind gusts and hail due to MUCAPE of 1000-2000
J/kg and deep-layer shear around 30 kts. Given the low confidence,
only have a low chance (less than 25%) for showers/storms occurring
over the region.

Any shower/storm chances end by late this evening. Attention then
turns to fog developing late this evening and continuing through
Saturday morning. Patchy dense fog is also possible, mainly in
central and northern WI. Any fog will lift by mid-morning Saturday.

Labor Day Weekend...High pressure and upper-level ridging will build
over the area into Saturday and remain in place through Monday,
leaving a dry forecast for the Holiday Weekend. High temperatures
will mainly be in the mid 70s to the low 80s, with dew points and
humidity levels at more comfortable levels compared to today
(Friday).

Rest of the extended...The ridge and high pressure will gradually
depart late Monday as return flow sets up ahead of an approaching
system progged to move over the area late Monday through early
Wednesday. It is too early to determine the severe potential, but
this pattern would favor strong/severe storms. Will need to monitor
over the coming days.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 105 PM CDT Fri Sep 4 2026

An area of low clouds with IFR and MVFR cigs prevailed across most
of the region early this afternoon. These clouds were becoming
more SCT at the east-central WI TAF sites as well. However,
anticipate the MVFR cigs to return to these TAF sites later this
afternoon into this evening, before dropping to IFR late this
evening. The IFR cigs will be accompanied by at least IFR vsbys
due to fog. Some spots could fall to 1/4SM as well. Conditions may
be at airport minimums at the TAF sites. Some improvement with
cigs and vsbys is anticipated by mid-morning Saturday.

There is still a very low chance (less than 25%) for isolated
storms to develop late this afternoon into this evening, but
coverage and confidence is very low for the storms to move over a
terminal; thus did not include a mention in the 18z TAFs.

&&

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

&&

$$

DISCUSSION.....Kruk
AVIATION.......Kruk

NWS GRB Office Area Forecast Discussion