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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

FXUS61 KCTP 192331

Area Forecast Discussion
National Weather Service State College PA
731 PM EDT Thu Sep 19 2019

Anomalous upper level ridging will build east into the region
late this week and during 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.


Upper level shear axis embedded and cresting the sharp upper 
ridge over the Ern GLAKS is maintaining an area of scattered mid
to high clouds extending from the eastern lakes southward 
through central PA this afternoon. Earlier stratocumulus which 
formed overnight in the easterly flow around the sprawling sfc 
anticyclone has mixed out over the Laurel Highlands, and it's
mostly sunny to sunny throughout central PA.

High pressure and low-pwat air mass will remain over the region
tonight, resulting in another mostly clear and cool night with
patchy late night valley fog. Expect min temps mainly in the


No changes to the going forecast on Friday as the strong surface
high slips south of the region. A return flow of warmer
southward flow will develop, and along with abundant sunshine,
temperatures should jump up to the mid to upper 70s north to the
lower 80s south/southeast.


A building upper level ridge and surface high off of the east
coast will bring a resurgence of summertime warmth across the 
area this weekend. Max temperature departures of +10-15 degrees
are expected Sat-Sun 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.

The biggest forecast question in the mid range will be the 
presence of a shortwave trough that will move through the Mid 
Atlantic region Saturday. This shortwave should flatten out the 
ridge and bring in some mid to upper level instability. The only
reducing factors is that it will be very dry aloft and their 
should be the presence of a low level cap. Temperatures will 
have to get very warm for the air to be able to be lifted beyond
it. Latest soundings show this is possible but given the dry 
air, less likely. 

So have introduced slight chance to chance POPS to central PA 
Saturday afternoon. 

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.


VFR conditions will continue into the early overnight hours,
before patchy fog and low clouds develop. Expect a period of 
IFR/LIFR cigs at KIPT just before daybreak, similar to the past
couple of nights. Also included some vsby reductions in patchy
fog at KBFD, KAOO and KUNV.

Any fog and low clouds will burn off quickly Friday morning, 
giving way to another day of VFR conditions. A light
southwesterly breeze around 5 knots will develop as the day

A few showers are possible Saturday, as a warm front crosses the
area. There is a better chance for showers/storms Monday, ahead
of an approaching cold front.


Fri-Sun...AM valley fog/possible, otherwise VFR. A few shra 
possible Saturday.

Mon...Chance of shra/tsra, as a cold front crosses the area.

Tues...Becoming VFR.


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




NEAR TERM...DeVoir/Fitzgerald
SHORT TERM...DeVoir/Fitzgerald
LONG TERM...Fitzgerald/Ceru