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676
FXUS61 KCTP 300926
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
526 AM EDT Fri Sep 30 2016

.SYNOPSIS...
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Showery conditions will prevail today and tonight, especially
across the southern half of the state. Unsettled weather with
occasional light rain showers will persist through the weekend
with a gradual drying trend by early next week.
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&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Two primary area of showers will continue through this morning,
mainly across southern and eastern portions of the forecast area.
The first plume of showers on a SE to NW axis across south-central
PA and the Laurel Highlands coincided with a strong 45 kt serly
LLJ, and enhanced upper level divergence/uvvel within the
thermally direct cell associated with the right entrance region
of a 90 kt/300 mb jet. The second area of mdt to hvy rain was
being created by a similarly strong, nearly 4 sigma, 40-45 kt
easterly 850 mb jet off the Atlantic transporting very high, 2-2.5
inch PWAT air over the coastal front.

Heaviest rainfall rates of 2-5 tenths of an inch per hour per
Dual Pol DPR product estimates are seen across the western Poconos
and portions of the Lower and Mid Susq River Valley.

The latest...07Z run of the HRRR tracks this area of enhanced
moderately heavy rain NWWD across the Middle and West branch
valleys of the Susq and north-central mtns during the mid to late
morning hours...before carrying it north of the PA/NY border by
14Z, leaving mainly scattered showers across the CWA for the
midday and afternoon hours.

Outside of these primary rain areas, look for overcast skies with
brief...scattered showers along with areas of drizzle and fog at
elevations AOA 1800 ft MSL.

Temps to start the day will be in the low-mid 50s in most
locations.

Winds will persist from the east to northeast at 8-12 kts.

The Large low will be quasi stationary and will continue to stream
moisture into Southwestern PA through much of today. Strong E-SE
LLJ and above normal PW along with associated forcing on
east/southeast side of upper low favors scattered to numerous
lighter rain showers through the period across the Laurels.

The highest rain chances this afternoon will once again be
focused across the SE half of the state, but should be generally
light and under 0.10 per hour, with 10-hour basin average amounts
mainly under 0.25 of an inch.

Afternoon max temps will only reach the upper 50s across the
higher terrain of the north and west...and lower 60s throughout
the valleys of central and southern PA.
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&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
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Greatest deep layer convergence appears to become focused across
the western mtns of PA tonight and early Saturday...before
shifting into Central PA for the late morning and afternoon hours
Saturday.

Expect to see rather low coverage of showers at any one time.
However, a few narrow north-south bands of mdt showers should
shift gradually east across the region during the day Saturday,
bringing additional light 12-hour rainfall amounts of 2 tenths or
less to many locations. A few locations could see over one half of
an inch where an hour or so of training showers occur.

Will follow the cooler EC and NAM guidance for max temps ranging
from the upper 50s across the higher...to mid 60s in the Susq
Valley on Saturday. GFS MOS guidance looks to be up to several deg
too warm considering solid overcast and persistent llvl easterly
flow.
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&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
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GEFS and latest operational models track the initially cut-off
upper level low slowly northward from the Lower Ohio Valley to
southern Lake Huron during the 12z Sat to 12z Sunday period.

The low will slowly blend into the upper level northwesterly  flow
over Sern Canada Sun-Mon and cold air advection will filter into
the region early into next week.

The final vestiges of the low that has dominated our weather
pattern this week will finally slide off the New England coast by
the middle of next week thanks to an upstream amplifying trough
over the central CONUS.

High pressure should regain control of our weather here in PA for
Tue into early Thursday. The 00Z GEFS appears to be in close
agreement with the previous 12Z GFS and EC with a path of
Hurricane Matthew from the Bahamas to near the Outer Banks of NC
during the 12Z Wed to 12Z Friday timeframe. The main concern here
in Central PA would be a period of enhanced...deep easterly flow,
clouds and perhaps a few periods of rain late next week...before
the storm begins to drift NE and away from the Carolina and Mid
Atlantic Coast.

Temperatures will be slightly below normal through the weekend,
before shifting to slightly above normal by the middle of next
week...then possibly dipping back to near normal as clouds (at
least the mid and high variety) thicken-up to the NW of Matthew.
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&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
Widespread MVFR-IFR conditions through tonight. Periods of rain
moving SE-NW across the airspace early today with decreasing
coverage by afternoon. Isolated LLWS possible 35-40KT from 090-120
degrees especially KBFD/KJST and may add with 09z update.

Outlook...

Sat...MVFR-IFR cigs. Ocnl -RA.

Sun...MVFR cigs. Chc -RA.

Mon-Tue...Gradual improvement likely.

&&

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

&&

$$
SYNOPSIS...Lambert/Steinbugl
NEAR TERM...Lambert
SHORT TERM...Lambert
LONG TERM...Lambert/Steinbugl
AVIATION...Steinbugl