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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

FXUS61 KCTP 201838

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

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.


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


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.


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 showers. It should move 
through the region quickly with a return to fair and seasonable 
weather appears likely Tue/Wed. High pressure should build 
southeast from the Grt Lks mid next week.


Valley fog will return late tonight with conditions at or below
airfield minimums most likely at KIPT. 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.


Sat-Sun...AM valley fog. Isold shra possible wrn 1/2 Saturday 

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

Tue...Becoming VFR.


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




SHORT TERM...DeVoir/Lambert
LONG TERM...Lambert/Ceru