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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 231824
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
224 PM EDT Sat Sep 23 2017

.SYNOPSIS...
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A ridge of high pressure at the surface and aloft will keep the
region dry through at Wednesday. A trough of low pressure will
bring cooler, more seasonable weather to the region by Thursday.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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Ridging continues. Surface obs show increase in surface moisture
to our west. With surface high slowly drifting east, look for
an increase in surface moisture overnight, making for a warmer
morning. Will keep mention of valley fog as well.
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&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
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Another summerlike sunny day with strong high pressure over the
state. There will be a noticeable increase in humidity with
more uncomfortable conditions as a result. Very warm with some
highs close to 90 across the SE zones. Warm and humid overnight
Sunday.
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&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
The large blocking high is made to remain over the region
through early next week as the remains of Jose continue to
weaken, with the models showing the circulation eventually
either dissipating or getting absorbed into the northern
periphery of the slowly advancing Hurricane Maria off the SERN
US coastline.

Shortwave energy is eventually made to track east through SRN
Canada causing our upper heights to begin falling by Wednesday.
At the same time Hurricane Maria is forecast to be moving
northward off the eastern seaboard. Models are trending closer
to the coast by the Wednesday-Thursday timeframe with several
members of the ECENS/GEFS actually bringing the storm very
close to or even hitting Cape Hatteras, before finally
recurving the storm out to sea south of the 40th parallel. The
main issue locally is whether we see any kind of marine
influence possibly bring some light rain/drizzle into my eastern
zone for Wednesday as is suggested by the ECMWF.

While the latter portion of the forecast will depend on just
how fast Maria moves north as the upper shortwave approaches the
area from the north, I used the blended MOS to put low chance
POPs in the forecast starting Wednesday. From that point it`s
still uncertain how fast and deep the northern stream shortwave
ends up being. There is reasonable agreement through Thursday
before the GFS speeds up and deepens the wave through the area
Friday. The ECMWF and the GEFS are slower and less amplified,
holding the most significant troughing off until the weekend
with a cooler showery pattern.

The bulk of the extended will be much warmer than normal, a true
late season visit from summer, before the pattern turns cooler
to end the new work week.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
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VFR conditions overnight. Patchy valley fog possible for a
couple hours near sunrise Sunday.

.Outlook...

Sun...VFR conditions.

Mon-Wed...Patchy AM valley fog possible. Otherwise VFR
conditions.
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&&

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

&&

$$
SYNOPSIS...Ross
NEAR TERM...Ross
SHORT TERM...Ross
LONG TERM...La Corte
AVIATION...Ross