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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

                            
000
FXUS61 KCTP 202312
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
712 PM EDT Fri Sep 20 2019

.SYNOPSIS...
Anomalous upper level ridging will build east into the region
through the weekend. A cold front will likely push across the 
area Monday, followed by high pressure building in from the 
Great Lakes by the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Deep layer moisture will slow increase tonight as a shortwave
trof embedded within the high amplitude upper ridge moves from
the central GLAKS to the eastern Lakes by 12z. PW increase to
over 1.0" over western third of PA by morning. Skies should be
mostly clear with the exception of some increasing high cloud
from the west by morning. Sfc ridge axis remains over central PA
providing another calm night. Mins won't be as chilly as recent
nights given return flow aloft, but should range through the 50s
in most places. A few upper 40s may pop up in sheltered northern
locations.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
No changes to the going forecast on Saturday as the strong 
surface high slips southeast of the region. A return southwest 
flow of warmer air will develop accompanied by partly to mostly
sunny conditions. Max temperature departures of +10-15 degrees
are expected Sat with peak readings in the mid to upper 80s in 
the SE. Max temperatures would have to reach or rise above 90F 
to challenge daily records in most locations.

Shortwave trough flattening the upper ridge should produce
enough marginal instability to keep slight shower chances going
over mainly the western mountains. Am not expecting eastern half
of central PA to see any shower activity.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Heights and temps aloft will rise again Sat night and Sunday, 
leading to a fair conditions at night and mostly sunny and a
pleasantly warm early Autumn day with temps well into the 70s 
across the northern and western mtns, and at least the mid 80s 
in the SE zones.

The models are coming into agreement on the tracking of a cold 
front that will move through the area Monday. This system will 
likely be accompanied by a round of generally light showers. It
should move through the region quickly with a return to fair 
and slightly warmer than seasonable weather Tue/Wed. High 
pressure should build southeast from the Grt Lks mid next week.

&&

.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
For the 00Z TAFS, looking at mainly clear skies with VFR
conditions.

I did edge fog off some, especially across the northwest.
This based on return flow from the southwest.

Most likely area to see fog is IPT.

Weighted fcst some to what occurred last night.

A spotty/isolated shower is possible mainly across the western
1/2 of the airspace Saturday PM. There is a better chance for 
showers/storms Monday PM, ahead of an approaching cold front.

.Outlook...

Sun...Mainly dry with VFR conditions.

Mon...Sct showers/isold t-storms as a cold front crosses the 
area.

Tue...Becoming VFR.

Wed...VFR conditions.

&&

.CLIMATE...
Autumn officially arrives at 3:50 a.m. EDT, on Monday, Sept. 23.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...
NEAR TERM...DeVoir
SHORT TERM...DeVoir/Lambert
LONG TERM...Lambert/RXR
AVIATION...Martin
CLIMATE...Steinbugl