931
FXUS63 KGRB 230251 CCA
AFDGRB

Area Forecast Discussion...CORRECTED
National Weather Service Green Bay WI
951 PM CDT Sat Aug 22 2026

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- Dry weather returns Sunday and Monday, with a period of
  unsettled weather arriving for the middle of next week.

- A Small Craft Advisory is in effect for central Green Bay and
  Lake Michigan nearshore waters north of Sturgeon Bay until 10
  AM Sunday.

- Slightly below normal temps this weekend, then a return to near
  normal readings for most of next week. Lows Sunday night may
  drop into the 30s north-central.

&&

.DISCUSSION...
Issued at 1242 PM CDT Sat Aug 22 2026

Near term through Sunday...Northwest flow and shortwave diving
across this afternoon during peak heating will result in isolated
to scattered showers through 7p, especially far northeast WI and
on across Door County. While weak deep layer shear (less than 25
kts) limits overall storm organization and the severe threat,
MLCAPEs up to 1000 J/kg, inverted-V soundings, very steep low-
level lapse rates, and lower freezing levels will promote some
gustier winds and small hail in the stronger showers/storms.
Northwest winds will be breezy at 15 to 25 mph this afternoon,
before diminishing this evening. Closer approach of sfc high will
bring dry weather tonight into Sunday. Upper trough (cold air
aloft) close enough to lead to another partly to mostly cloudy
afternoon as fair weather cu blossoms. Northwest winds will be a
little lighter on Sunday, but could still gust to 20 mph.

Extended...Dry, but chilly Sunday night with high overhead and low
PWATs allowing for good radiational cooling. MOS guidance already
suggesting that typical cold spots up north could drop into the
mid to upper 30s. Next chance for showers and some storms arrives
Tuesday afternoon through Wednesday afternoon as a sharp mid-
level trough and sfc cold front work through. If cold front is
slower on Wednesday (ECMWF), there would be better chance for a
few stronger storms over eastern WI that afternoon. Instability
appears modest with this mid-week feature, keeping severe risk
low. Machine learning is mixed at best on severe potential. Then,
similar to today post fropa, steeper lapse rates and peak heating
may yield another round of isolated to scattered showers and
storms on Thursday.

Temperatures...After the cooling this weekend into early Monday,
temps return to near or even slightly above normal with highs
mainly in the mid 70s to low 80s. Normal highs for the coming
week start off in the 77-78F range, but by next weekend fall off
into the mid 70s.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 944 PM CDT Sat Aug 22 2026

Very isolated areas of mid-clouds exist, but skies have cleared
for the most part across northeast WI. Mainly clear skies are
expected through 15Z Sunday morning. With a modest pressure
gradient, MOS guidance shows little to no fog threat, but will
monitor as climatology would suggest some patchy fog is possible
across the northwoods where rain occurred this afternoon.

Fair weather clouds will likely build with daytime heating 15-16Z
Sunday. Cloud bases will remain VFR (5-6 kft) which will gradually
rise through the afternoon. The clearing is expected early Sunday
evening.

Northwest winds will remain breezy on Sunday with gusts 14-18 kts.

&&

.MARINE...
Issued at 1242 PM CDT Sat Aug 22 2026

Northwest winds of 10-20 kts with gusts to 25 kts expected tonight
into Sunday morning behind re-inforcing cold front. Have hoisted
Small Craft Advisory for the central Bay and for Lake Michigan
nearshore waters north of Sturgeon Bay. Strongest winds will be
near Death`s Door and Washington Island. Offshore winds will
limit waves to 1 to 3 ft for most spots on the bay and nearshore
waters, with any 3-4 foot waves staying in the open waters.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......MPC
MARINE.........JLA

NWS GRB Office Area Forecast Discussion