Area Forecast Discussion
Issued by NWS State College, PA-- Remove Highlighting --
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FXUS61 KCTP 300640
Area Forecast Discussion
National Weather Service State College PA
240 AM EDT Fri Sep 30 2016
Showery conditions will prevail through today, especially across
the southern half of the state. Unsettled weather with occasional
light rain showers will persist into the weekend with a gradual
drying trend by early next week.
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
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 4-8 tenths of an inch per hour per Dual
Pol DPR product estimates are seen across the western Poconos and
areas just east of the Lower Susq River. Latest HRRR tracks this
area of enhanced rain NWWD across the Middle and West branch
valleys of the Susq and north-central mtns during the mid to late
Across much of the remainder of central and northern PA, look for
overcast skies with brief...scattered showers along with areas of
drizzle and fog at elevations AOA 1800 ft MSL.
Temps will be steady in the low-mid 50s across the western half of
the state, and mid to upper 50s in the east, and will be steady or
fall just a deg f or two early today.
winds will persist from the east to northeast at 8-12 kts.
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM SATURDAY/...
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.
Elsewhere, the area of enhanced rain impacting the region form the
Middle Susq Valley to the North-central Mtns early in the period
with break up into generally scattered showers by the early
afternoon hours today.
Greatest rain chance 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.
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 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.
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
The upper level low will continue to spin slowly northward into MI
and continue on into Southern Canada. The low will slowly be
pulled into the upper level flow 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 lift and move off coast by mid next week by the upstream
amplifying trough over the central CONUS. High pressure should
regain control of the large scale pattern. The 12Z GFS comes more
into alignment with the EC however the EC continues the path of
the TC Matthew much slower and keeps it off the coast of Florida,
where the GFS brings the projected path up the Atlantic coast and
has the system nearing the NC coast by Thursday morning.
Temperatures will be slightly below normal through the weekend,
before shifting to slightly above normal by the middle of next
.AVIATION /06Z 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.
Sat...MVFR-IFR cigs. Ocnl -RA.
Sun...MVFR cigs. Chc -RA.
Mon-Tue...Gradual improvement likely.