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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

FXUS61 KCTP 200855

Area Forecast Discussion
National Weather Service State College PA
455 AM 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.


Surface ridge over Eastern PA and northern flow aloft will
maintain abundant sunshine and low precipitable water values of
less than 0.60 inch for the bulk of the area today...yielding
nothing more than a few spotty flat cu over the far NW and
perhaps the Laurel Highlands, with just some patches of thin
cirrus elsewhere. 

Any patchy valley fog across the north will dissolve by 1330Z. 

Winds will be light and variable throughout the day with temps 
rebounding from chilly early morning readings in the mainly in 
the 40s (upper 30s throughout the perennial cold spots in the 
northern mtns) to the mid and upper 70s for mid afternoon maxes.
The high temps will be a few to svrl deg F above normal.


No changes to the going forecast on Saturday as the strong 
surface high slips southeast 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 over the weekend appears to be in
regard to a shortwave trough that will move out of the Ohio
Valley and into the Mid Atlantic region Saturday. This 
shortwave should briefly flatten out the upper level ridge and 
bring in some marginal instability. 

Sfc-based capes will climb to between 1000-1500 j/kg in the 
afternoon hours Saturday, and there will be some pockets of 
slightly cooler mid- level temps of 5-6C over the west, while 
the east should maintain 700 mb readings AOA 7C. 

Will maintain a slight chance to chance of mainly showers for
the western mtns, but remove mention of any appreciable showers
east of a KELM to KHGR line.

Heights and temps aloft will rise again on Sunday, leading to a
mostly sunny and 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/localized restrictions early this morning will give
way to widespread VFR shortly after sunrise. Persistence trends
favor northern tier airfields KBFD/KIPT with brief IFR 
conditions around daybreak.

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.


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

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

Tues...Becoming VFR.


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




NEAR TERM...Lambert
SHORT TERM...Lambert
LONG TERM...Lambert/Ceru