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-- Discussion containing changed information from previous version are highlighted. --
478
FXUS61 KCTP 201410
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1010 AM EDT Wed Sep 20 2017

.SYNOPSIS...
A ridge of high pressure at the surface and aloft will extend
across Pennsylvania through next Tuesday. This dominant weather
feature will provide fair, warm and generally dry weather
for this entire period.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Visible satellite shows slow decay of fog and stratus over
central PA. Any remaining fog/stratus will decrease in next
couple hours leaving the region with a sunny and warm afternoon.
Temperatures will range from the upper 70s across the higher
terrain of the north and west, to the lower 80s (and maybe a few
mid 80s).
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
The broken record continues for tonight and Thursday under the
persistent ridge along the spine of the Appalachians. mainly
clear skies, light wind and a slight bump up in sfc dewpoint
will provide optimal conditions for another night of locally
dense and fairly widespread valley fog.

Low temps early Thursday should be 2-4 deg F milder than early
Wednesday, and similar increases in high temps from the prior
day are also expected with highs near 80F across the nrn and wrn
mtns, and low to mid 80s elsewhere.

Sky cover (after the dissipation of the morning fog) will be
generally scattered with some flat afternoon cu and areas of
thin cirrus.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The overall pattern hasn`t changed much, there is a good
overall consensus in the models for the end of the work week.
For much of this period, a 590 dam closed 500 hPa high will
drift slowly out of the midwest states, and become centered over
western PA by late this weekend through early next week.

The GEFS forecasts showed this feature as a closed 5880 m ridge
over us with near +2 sigma above normal heights which will
translate to well above normal temperatures. High temps from
Friday through the weekend will be 10-15F above normal with
little or no chance of rain until Monday at the very earliest.

Lows early each morning will be consistently in the mid and
upper 50s across the northern and western mtns, to lower 60s in
the larger SE metro areas.

Min temps may cool off slightly for this weekend thanks to deep
dry air and a light N to NW llvl flow of drier dewpoint air at
the sfc.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
GOES-16 fog channel imagery shows widespread valley fog
confined mainly to the west of the Susquehanna River. The outer
edge of cloud shield associated with TS Jose is drifting over
the southeast airfields and has precluded fog formation. Locally
dense fog will produce local cig/vis AOB airfield minimums.
Expect fog to dissipate through mid morning with VFR conditions
this afternoon and evening. Persistence fcst favors more fog
restrictions late tonight into Thursday morning.

.Outlook...

Thu-Sun...Patchy valley fog possible each morning. Otherwise
VFR with generally light winds and minimal clouds.

&&

.CLIMATE...
Astronomical Fall/Autumnal Equinox begins at 4:02 PM Friday
September 22, 2017.

&&

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

&&

$$
SYNOPSIS...Lambert/RXR
NEAR TERM...Ross
SHORT TERM...Lambert/RXR
LONG TERM...Ceru/Gartner
AVIATION...Steinbugl
CLIMATE...