Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 222310

Area Forecast Discussion
National Weather Service Green Bay WI
610 PM CDT FRI JUL 22 2016

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Saturday
Issued at 226 PM CDT Fri Jul 22 2016

Sunny skies and less humid weather prevailed across the cwa this
afternoon. This quiet weather is expected to persist into the
overnight hours with a high pressure in control of the western
Great Lakes. However light winds, clear skies, and remaining low
level moisture could once again lead to some patchy fog formation.
Lows tonight are forecast to settle into the 60s.

The main forecast concern on Saturday will be the possibility for
afternoon convection ahead of an approaching cold front. The
models offer many different solutions Saturday, with some models
developing an MCS that tracks into central Wisconsin by Saturday
afternoon, with other models dry for much of the afternoon. Given
the models performance as of late has been less than stellar and
the best instability remains to our southwest on Saturday prefer
the slower solution with this forecast. Therefore will maintain
chancy pops across the western cwa in case this system pushes in a
bit faster, but shy away from likely pops as this solution is not
the expected outcome. Highs Saturday should be a degree or two
below today given debris clouds from upstream convection is
expected to track over the area, even if the system itself holds
off a bit. Heat indices are expected to rise into the upper 80s to
lower 90s, with a few readings in the middle 90s given the dew
points generally remain in the 60s. Therefore no heat headlines
are anticipated at this time.

.LONG TERM...Saturday Night Through Friday
Issued at 226 PM CDT Fri Jul 22 2016

Little change from previous forecast as low amplitude upper level
flow is expected over the region during most of this forecast

Thunderstorms for Saturday night and Sunday are the primary
concern as cold front moves across Wisconsin and a mid level
short wave trough moves across the region. Still some question as
to exact location, but it appears an MCS of some sort will form to
the west and move east or southeast and weaken as it traverses the
forecast area. While instability and PWATs indicate likely POPs,
the eastward extent of the severe threat is still uncertain. SPC
Day 2 looks reasonable.

There will be a narrow window on Sunday for isolated convection
until the front passes through mid-day, but debris clouds and a
freshly overturned atmosphere make adding details to Day 3
convective chances difficult.

The next chance for precip will be later Tuesday/Wednesday as yet
another shortwave trof or two moves through.

Temps AOA normal through mid-week.

.AVIATION...for 00Z TAF Issuance
Issued at 606 PM CDT Fri Jul 22 2016

VFR conditions will prevail across much of the region through late
Saturday morning. The only exception may be for some patchy MVFR
visibilities due to fog between 07z and 11z. Thunderstorms will be
on the increase later Saturday afternoon across portions of
central Wisconsin. A thunderstorm complex is expected to move
across the region Saturday evening into early Sunday morning. This
complex should make it into central/north central Wisconsin by mid
evening and into northeast Wisconsin by late evening. Torrential
rain, strong wind gusts and hail may accompany the stronger




SHORT TERM.....Kurimski
AVIATION.......Eckberg is the U.S. government's official web portal to all federal, state and local government web resources and services.