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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 212320
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
720 PM EDT Wed Jun 21 2017

.SYNOPSIS...
A weak cold front will stall out just south of Pennsylvania
tonight, then return north as a warm front on Thursday. A deep
upper level trough will approach the region, bringing increasing
humidity along with the chance for showers and thunderstorms
late Thursday into Saturday. Drier and cooler conditions will
return later in the weekend into next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Radar showing scattered convection along weak cold front pushing
south of the Mason Dixon Line at 22Z. This boundary is progged
to stall out just south of the state overnight, and it`s
associated showers/storms are expected to dissipate with loss of
heating after sunset.

A push of low PWAT air in the wake of cold front should result
in a fair and dry night across central Pa with scattered cumulus
giving way to clear skies across most of the region after
sunset. Temperatures will fall into the 40s over the north and
range to around 60 over the SE. This expected cooling down near
the dewpoint in most areas should equate to areas of fog late at
night, especially in the valleys and areas where rain has fallen
this afternoon.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
Thursday will start out partly cloudy and comfortable with the
patchy early fog as a bubble of high pressure slides SE and
over us for late morning.

The low level flow will strengthen from the SW during the
afternoon bringing in noticeably more humid air along with an
increasing chance of an afternoon or evening shower or
thunderstorm.

PWATs will increase from below normal (only 15-20 mm this
morning) to over 40 mm (or 1-2 sigma) by 00Z Friday just to the
west of the approaching warm front.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
From a large scale perspective, the medium range forecast will
feature a seasonably strong/amplified upper trough settling over
the Northeast U.S into next week. Expect moisture/rainfall
associated with the remnants of TS Cindy to exit the area by
the start of the weekend. Confidence is low with details
(timing) with multiple shortwaves reflecting surface
fronts/troughs inducing risk for isolated to scattered showers
and Tstorms Mon-Wed.

By Friday the tropical airmass will have re-established itself
with dewpoints well up into the 60s and lower 70s over the
entire region making for a sticky end of the work week. Model
consensus continues to signal rain on Friday/Friday night
corresponding with a peak in H85 moisture flux and PW. The
heaviest rain is fcst to stay to the south of PA.

Drier, low PW air arrives by early Saturday and lasts through
the weekend. This should translate into comfortable, low-
humidity conditions with temperatures near to slightly below
late June climatology. Precipitation opportunities will be
modulated by several shortwave impulses which have low
predictability at this range. Any rains would be generally
scattered and on the lighter side given overall lack of deep
layer moisture. 21/12z GEFS shows PW values remaining below
average into midweek.

Temperatures should stay on the cooler side of climo through
midweek as the upper level trough shifts east of the area. FWIW
the GFS is more bullish vs. EC on heights rebounding/building SE
U.S. upper ridging into the second half of next week. That
said, there is general agreement in a modest warming trend later
next week as the trough moves out and heights return to normal.

&&

.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
VFR conditions will continue through the evening hours.

Any remaining convection will dissipate by an hour after sunset.
Initially mainly clear skies and quickly diminishing wind will
likely lead to areas of valley fog during the overnight hours
(mainly where rain falls today).

A warm front will approach the region Thursday triggering
showers and scattered thunderstorms, mainly over the west and NW
during the afternoon.

.OUTLOOK...

Fri...Widespread sub VFR likely with rain and embedded
thunderstorms.

Sat-Sun...Mainly VFR

Mon...Mainly VFR. Chc SHRA/TSRA.
-- End Changed Discussion --

&&

.EQUIPMENT...
KCCX radar will be offline for approximately 4 days starting
Saturday, June 24th for technicians to install the first of 4
major service-life extension upgrades. The work on the radar has
been scheduled to minimize potential impacts to operations and
will be delayed if hazardous weather is forecast.

&&

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

&&

$$
SYNOPSIS...La Corte
NEAR TERM...Fitzgerald/La Corte
SHORT TERM...La Corte
LONG TERM...Steinbugl
AVIATION...La Corte/Gartner
EQUIPMENT...