Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 291953
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
353 PM EDT Thu Sep 29 2016

.SYNOPSIS...
Showery conditions will prevail through tonight...with additional
moderate to locally heavy rainfall possible over the higher
elevations of the southern tier of central Pennsylvania through
early Friday. Only minor flooding impacts are likely across the
southern portions of central PA. Unsettled weather with
occasional lighter rain showers will persist into the weekend with
a gradual drying trend by early next week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
2.5 to 3.5 inch amounts feel across southern tier overnight
through midday...with higher amounts likely on the east facing
slopes occurred across the southern tier. Flooding threat
remains...albeit low...with upslope areas susceptible to any
persistent upslope or training convective showers over the next
18 hours which could add another 1 to as much as 2 inches in some
spots.

Dry slot over western PA with high cloud covering eastern brought
transition to low topped open cellular activity propagating from
southeast to northwest today. Thus a more showery regime took over
with times of little or no rainfall and other times with brief
moderate to heavy rates accumulating a few tenths of an inch at
time.

Moderate PW transport along with some elevated instability will
maintain a favorable environment for mdt-heavy rain/efficient
rainfall processes through this evening, while increasingly
diffluent flow aloft supports some training bands in addition to
the trend to low topped open cellular character. In
fact...training bands have organized over nrn VA/MD at mid
afternoon and are moving into the Laurels and South Central
Mountains...as anticipated earlier.

Still expecting storm totals of 2-4" over the remaining flood
watch area with locally 5"+ possible along the east-facing slopes
and highest terrain. Very dry antecedent conditions resulting in
3-6hr FFG values of 4+ inches along with below normal stream flows
should help to mitigate flooding to some extent, however if the
higher end amounts are realized flooding impacts/runoff issues
could become more serious.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...

The Large low will be quasi stationary and will continue to stream
moisture into Southwestern PA through tomorrow.  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.  The mid range models are
keying in on a mid level short wave trough that forms to the east
of the low and should increase rainfall rates and amounts through
Central PA as it is coupled with the LLJ and the PWATS.


&&

.LONG TERM /FRIDAY 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
week.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
Low cigs and shra persist across PA through Friday. Expect
predominantly IFR cigs through tonight at the higher terrain
airfields, including KBFD, KUNV, KAOO and KJST. At the lower
elevation airfields, while mvfr with sporadic ifr expected farther
north.

Outlook...

Fri-Sat...Low cigs/showers likely, mainly w mtns.

Sun...AM low cigs possible.

Mon...Showers/cig reductions possible at KBFD.

Tue...Fair.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Friday morning for PAZ025-026-033>036-064-
065.

&&

$$
SYNOPSIS...DeVoir/Steinbugl
NEAR TERM...DeVoir/Steinbugl
SHORT TERM...DeVoir/Ceru/Steinbugl
LONG TERM...Ceru/Steinbugl
AVIATION...DeVoir/Fitzgerald


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