200
FXUS63 KGRB 220325
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1025 PM CDT Tue Jul 21 2026

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- Scattered light showers ending by late afternoon and breezy
  winds subsiding toward sunset. Small craft advisories are in
  effect through early Wednesday morning.

- Comfortable and quiet conditions through Friday, followed by
  increasing heat, humidity, and thunderstorm chances (30 to 50
  percent) over the weekend.

&&

.DISCUSSION...
Issued at 218 PM CDT Tue Jul 21 2026

A subtle west to east sfc trough is moving swd across the area
with a wind shift from nwly to more nly expected. Scattered
light showers are ahead of and along the trough with drier air
and isolated showers behind the trough. The cold advection
will continue tnt as the 992 mb low just south of James Bay
lifts newd into north central Quebec through tomorrow. Cloud
cover will gradually clear through the evening with the loss of
heating and the arrival of drier air. Low temps in the 40s are
forecast for ne WI with lower to middle 50s over the Fox Valley.

On Wednesday, a shortwave trough will move across the nrn Great
Lakes to srn Ontario, while high pressure will track from the
nrn Great Plains to sw WI and ne IA. Lingering cool air aloft
will lead to broken cloud cover for a time on Wed, with high
temps mainly in the lower to middle 70s.

A relatively dry airmass and gradually warming temperatures back
to near normal are anticipated for Thu-Fri as high pressure
tracks from nrn IL to the lower Great Lakes.

Shower and thunderstorm chances return to the forecast for the
weekend and early next week. Nwly flow aloft will continue with
embedded shortwave troughs. There may be a couple low pressure
areas that track across srn Canada or the nrn USA and affect ne
WI and east central WI. High temperatures in the 80s are
forecast with increasing relative humidity.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1022 PM CDT Tue Jul 21 2026

Winds continue to diminish overnight as VFR conditions prevail.
On Thursday, fair weather cumulus will develop between four and
six thousand feet. The may be a period where skies become a broken
deck, but will be in the VFR category. Northwest winds continue
on Wednesday between 5 and 10 knots with gusts to around 15 knots
by mid to late morning through the afternoon. Winds become light
and variable Wednesday evening.

&&

.MARINE...
Issued at 218 PM CDT Tue Jul 21 2026

Breezy nly winds will continue for much of the night with the
Small Craft Advisory in effect until 4 AM CDT Wed. Light to
modest nnwly winds are expected on Wed with lake breeze
development possible by mid to late afternoon. Light wly winds
Thu AM are expected to become modest sly winds for Thu
afternoon.

&&

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

&&

$$

DISCUSSION.....MG
AVIATION.......Eckberg
MARINE.........MG

NWS GRB Office Area Forecast Discussion