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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 280844
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
444 AM EDT Wed Jun 28 2017

.SYNOPSIS...

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High pressure will move off the eastern seaboard later today
setting up a warmer and more humid airflow beginning on
Thursday. A cold front on Saturday will bring a brief break in
the humidity.
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&&

.NEAR TERM /THROUGH TONIGHT/...

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Satellite shows a small area of low/mid clouds immediately
downwind of Lake Erie moving slowly off to the SE. They seem
associated with a very weak ripple in the mid level flow as seen
by the RAP, but not causing any precip. Otherwise skies are
clear to scattered and the GOES R Nighttime Microphysics
channel shows nicely how the northern valleys have filled with
fog.

The fog will burn off quickly under the high summer sun leading
to a bright sunny day with highs averaging in the 70s. Quite
pleasant with a light wind, yet still several degrees cooler
than normal. It will be the last cooler than normal day we will
see for a while.

The high will move overhead today and east of the area by
tonight setting up a warmer and eventually more humid SW flow.
The overnight will see a gradual increase in clouds from the NW
with another comfortable sleeping night in store with dewpoints
still only in the 50s.
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&&

.SHORT TERM /THURSDAY/...

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By Thursday the eastern US will be under a broad upper ridge,
but close to the southern edge of the main westerlies. A warmer
and more humid airmass will begin to advect into the region
between the offshore high and a low moving north of the Gr
Lakes. Deterministic models develop a fair amount of CAPE and
mid level lapse rates are forecast in the 6-7C/km range, so an
afternoon shower or thunderstorm is likely in a few spots. I
used the blended MOS POPs to favor the northern 1/3-1/2 of my
CWA for the best chance of rain in the afternoon.
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&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...

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The upper pattern starts out with the broad ridge and high
heights over the eastern US, before eventually becoming more
broadly cyclonic, but still with heights remaining seasonably
high as most shortwave energy slides through southern Canada.

Friday will be warm and humid with diurnally driven
showers/storms possible. The deterministic ECMWF/GFS both show
the mid levels being relatively warm suggesting coverage will
be on the scattered side.

A cold front is progged to be entering the region Saturday and
moving east of the CWA early Sunday, so we should see a better
chance of more widespread rain. The front is expected to be
weak, so temperatures behind it will not change much, just a
bit of a break in the humidity for the second half of the
weekend.

Sunday Night into early Tuesday look mainly dry as high pressure
builds over the region. The cold front will begin sliding back
north as a warm front Tuesday into mid week, bringing renewed
humidity and increased chances for the usual summertime showers
and thunderstorms.
-- End Changed Discussion --



&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
High pressure building into the area from the Ohio Valley will
supply mainly VFR conditions and light wind tonight across
central Pa. Only area of concern is BFD, and to a lesser degree
IPT. Both locations received rain showers making those spots
more susceptible to fog overnight.
 Winds have gone calm at BFD and dewpoint depressions are within
1. Given that and the clear skies I have TEMPO group for MVFR
vsbys beginning at 09Z.
 At IPT, the rain was lighter and would put the odds of
significant (IFR) reductions there at around 10 pct. Plus winds
remain persistent at IPT which should further reduce chances of
fog/mist formation.  Elsewhere, confidence is very high in VFR
conditions overnight.

Any patchy fog that may form overnight should burn off by around
13Z Wednesday. High pressure over the region should ensure VFR
conditions and light winds for the rest of the day.

.OUTLOOK...

Thu-Fri...Isolated PM tsra impacts poss, mainly northern Pa.

Sat...Scattered PM tsra impacts possible.

Sun...No sig wx expected.

&&

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

&&

$$
SYNOPSIS...La Corte
NEAR TERM...La Corte
SHORT TERM...La Corte
LONG TERM...La Corte
AVIATION...Fitzgerald/Ceru