Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 010844

Area Forecast Discussion
National Weather Service Green Bay WI
344 AM CDT SAT OCT 1 2016

Forecast discussion for routine morning forecast issuance

Issued at 342 AM CDT Sat Oct 1 2016

Cloudy with scattered showers today, then more sunshine and warmer
for a few days.

The large scale flow across the eastern Pacific is amplified. But
the wavelength between a trough driving east across the
Aleutians, a ridge over the Gulf of Alaska, and a trough off the
West Coast is very short. That will be resolved by a fairly quick
eastward progression of the West Coast trough initially.
Progression will slow considerably during the latter part of the
forecast period, once the wavelength is longer. Meanwhile, a
cut-off low located over the Ohio Valley will drift north for
another day or so before getting shunted off to the east by the
trough approaching from the west.

Temperatures will be held back by clouds and scattered showers
today, then return to above normal through the middle of next
week. A turn to cooler weather is likely at the end of the week.
Two main opportunities for precipitation exist. The first will be
with the cut-off drifting back toward the area today into tonight,
and another with the passage of a cold front trailing from a
cyclone tracking across Canada next week. The 2 events will
likely result in amounts near or a little below normal for the

.SHORT TERM...Today...Tonight...and Sunday
Issued at 342 AM CDT Sat Oct 1 2016

The main short-term forecast issue continues to be handling of
precipitation associated with the northward return of the cut-
off. The forecast is basically for scattered showers the next 24
hours, mainly in the east. Added some temporal resolution to the
PoPs to account for the rain band currently wrapping west across
the area, and another likely to work into the far east late today
and this evening.

Rain chances will slowly decrease from west to east overnight,
followed by a similar decrease in clouds on Sunday. But it may
take much of the day to get an appreciable decrease in clouds in
east-central Wisconsin.

Clouds and scattered showers will hold temperatures back again
today in the east. Now that the upper low is closer, at least
some middle clouds will wrap back across the west/northwest part
of the area, keeping those areas a little cooler than yesterday.
Used a blend of the top performing guidance products and the
standard broad-based blend of guidance for the temperature

.LONG TERM...Sunday Night Through Friday
Issued at 342 AM CDT Sat Oct 1 2016

Forecast concerns revolve around precip chances midweek when a large
cyclone migrates across the northern Great Plains and sends a cold
front across the region. Plenty of differences in regards to the
track/strength/timing of the cyclone by next Wed, and each
operational model has support from its respective ensemble mean.
Therefore, no clear model preference tonight, so will continue with
a gfs/ecmwf blend.

Sunday night through Monday night...Upper low pressure will be
moving over the eastern Great Lakes on Sunday night and Monday as
surface high pressure moves across the state.  Skies will continue
the clearing trend on Sunday night, and combined with light winds,
conditions will support fog formation late.  Will hit stronger fog
coverage in the forecast.  Quiet conditions will persist on Monday
and Monday night.  With light east flow off Lake Michigan, will
likely see areas of scattered to broken lake clouds over eastern WI
during this period.  No significant changes to temps.

Rest of the forecast...High pressure will be sliding to the east on
Tuesday and Tuesday night, but the next system still looks too far
upstream to have any impact on our weather.  This will change on
Wednesday through Thursday morning, when a cold front slowly moves
east across the region.  Forcing looks strong enough for widespread
showers and a few storms, but some timing differences still need to
be ironed out.  At this time, the best period of rainfall looks to
occur Wednesday afternoon into Thursday morning.  Colder air will be
sliding in behind the front for Thursday into next weekend.  Though
there is some differences in regards to how cold this airmass will
be, potential will be there for the first widespread frost/freeze,
possibly on next Friday night.

.AVIATION...for 12Z TAF Issuance
Issued at 342 AM CDT Sat Oct 1 2016

Ceilings were quite variable across the area, ranging from MVF
with mid-clouds across the northwest to IFR in the far southeast
part of the area. That general cloud distribution will continue,
though ceilings in the west will lower today. Suspect most
guidance is too low for visibilities for tonight, though MVFR and
IFR ceilings are again likely in the east.



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