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Area forecast discussion 
National Weather Service State College PA
140 am EDT Thursday Aug 28 2014

a cold front will clear the southern tier of the state overnight.
High pressure will arrive behind the front and bring dry weather
to the area through the end of the week. Above normal temperatures
and increasingly humid and unsettled conditions are forecast over
the Labor Day Holiday weekend and into the first week of


Near term /until 6 am this morning/...
cap was fairly stubborn this evening...but isolated to scattered
coverage of showers and thunderstorms did evolve along and ahead
of the front over the southeast half of the commonwealth during
maximum heating. Zone of greatest instability extended from the
Laurel Highlands to the middle Susquehanna River valley where mesoscale
analysis depicted convective available potential energy locally exceeding 1200 j/kg. Several
storms garnered sufficient concern for spss and even a few for
warnings given their vertical development...but with little
ambient wind to work with and insufficient cold pool severe reports have been fielded thus far.

For the overnight...isolated shower and thunderstorm activity
continues to weaken along and ahead of the slowly southeastward advancing
surface front...which extends at this hour from just southeast of kjst
northeastward to near kipt.

Drier air will continue to filter southeastward from the central mountains
south and east through the pre dawn hours. Skies have cleared
across the north...but a patch of cirrus extends from Southern
Lower Michigan through Northern Ohio which will filter across
central areas overnight. Isolated showers will end across the
south as the front clears my southern counties. Decoupling is
expected in most areas...leading to the usual River Valley fog
early Thursday morning. Mins should range from the refreshing
upper 40s north to the l60s in the southern tier.


Short term /6 am this morning through 6 PM Friday/...
cool Post-frontal northwest flow will make for a mostly sunny day over
most of the region. The only fly in the ointment might be the
approach of a lower cloud deck from the north/NE as a strong port maximum
drops S across New York state. Will keep probability of precipitation up near isolated numbers in
the NE...but not mention precipitation quite yet. A sprinkle is possible
in the NE though. Maxes will be about 8-10f below Wednesday/S
lofty numbers.


Long term /Friday night through Wednesday/...
the medium range flow pattern will feature troughing in the west
and fairly high heights forecast to prevail over the east supported
by a subtropical ridge that should anchor over the southeast. This
ridge will allow high pressure to center over upstate New York at the
start of the period. This will slowly move off the New England
coast on Saturday. A long frontal boundary extending from an upper
level low centered over northern Canada...and to a negatively
tilting trough which should be moving into the Midwest. The
biggest moisture from the frontal boundary is prognosticated to stay
north of PA.
However...there should be enough moisture...with enough forcing
to warrant increasing probability/opportunity for rain Saturday
night into early Monday. Daytime convection will also be spurred
on by a warming trend with maximum temperatures 5-10f above normal over the
weekend and into the first week of sept. The best chance for
precipitation through this timeframe should be Sunday afternoon
into Sunday evening. There is some model variation so expect some
modifications as time progresses. A GFS and ec in the long range
are actually in fair agreement through the first half of next
week...including the substantial trough that should move through
Wednesday as more defined cold front should approaches the area.


Aviation /06z Thursday through Monday/...
a cold front continues to push slowly southward across the
state. Drier air filtering in on northwest flow...will continue
to work southward overnight.

Most areas are clear of lower and middle level clouds...but a patch of
cirrus is across the area.

Valley fog is expected in the northern valleys as the temperatures drop off
well below the river water temperatures. But there could be a little wind
which could impede fog formation. Will keep MVFR fog in most tafs
and IFR fog in bfd for a few hours late. Only made minor adjustments
to 06z tafs.

The northwest winds pick up after sunrise but skies and visible should
quickly improve to VFR and remain there through the day. A low-
end VFR cloud deck may drop down from western New York state during the
daylight hours. For now...most of the clouds will likely be at
bfd. Middle level warm air and low dewpoints working in will limit
cumulus otherwise.

Friday...early morning fog with restrictions likely. Otherwise VFR.

Sat-Mon...mainly VFR. Scattered showers/tstms.


Ctp watches/warnings/advisories...


near term...dangelo/devoir
short term...dangelo
long term...ceru/steinbugl

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