534
FXUS63 KGRB 221053
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
553 AM CDT Tue Sep 22 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Hazardous boating and swimming conditions are expected on the
  Bay and Lake through this evening.

- Patchy areas of frost are possible early this morning across
  north-central WI. Additional periods of frost are possible
  through the week.

- Dry and quiet weather will settle in across the region for the
  rest of the week.

&&

.DISCUSSION...
Issued at 102 AM CDT Tue Sep 22 2026

A large area of high pressure will keep the weather dry for the
rest of the upcoming week. Mostly clear skies and cool
temperatures may lead to patchy frost across north-central
Wisconsin in protected and low laying areas tonight.

NWP models do ram a low pressure system into the high for the
upcoming weekend. However, as often is the case in these
scenarios, the high ends up winning and we end up drier or the low
tracks through a bit later than forecast this far out. Therefore,
while there are some small (20-30%) POPs in the forecast this
weekend, the expectation is any rain wouldn`t be a soaker with a
chance this system could dry up or be delayed by the Hudson Bay
high that is expected to be in place.

Looking ahead the next chance for any appreciable rain does not
look like it would be a possibility until the early to middle part
of next week when the high retreats, allowing a trough to track
through the western Great Lakes. Again, given the tendency of
these high pressure systems, this could be delayed even further.

Temperatures this week will gradually trend warmer each day with
highs climbing back into the upper 60s to low 70s by the weekend.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 552 AM CDT Tue Sep 22 2026

VFR conditions are expected for most of the TAF period as high
clouds over 15k ft spread in across the region at times. The main
exception will be this morning when some lower MVFR clouds will be
noted at times in isolated pockets, especially near Lake Michigan.
Skies then clear out tonight, with VFR conditions expected across
the region.

East or northeast winds are expected through the TAF period,
gusting to ~15 kts, locally higher near the bay/Lake Michigan.

&&

.MARINE...
Issued at 102 AM CDT Tue Sep 22 2026

The primary immediate weather hazard involves elevated winds and
high waves on the Bay and Lake. The pressure gradient between the
robust high pressure over northern Ontario and the advancing low
pressure to our west is producing onshore winds to 20 kts and wave
heights to 6 feet on Lake Michigan, and 3 to 4 feet on the Bay of
Green Bay.

The gusty northeast winds will veer to the east today and remain
gusty in the 20-25 kt range. As a result, Small Craft Advisories
and a Beach Hazards Statement look to remain on track. Although
winds and waves might subside a bit on the bay this morning, they
do pick up again this afternoon. Therefore, will leave the current
headline in place.

Winds and waves will gradually subside late tonight into
Wednesday as the pressure gradient begins to relax. At this time
it appears winds and waves will stay elevated on the Lake through
at least midnight. Therefore, will extend the headlines for these
areas through midnight with a possible further extension into
Wednesday morning as the waves subside from north to south.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 7 AM CDT this morning for WIZ005-010>012-
018.

Beach Hazards Statement through this evening for WIZ022-040-050.
&&

$$

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

NWS GRB Office Area Forecast Discussion