National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 291634
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1234 PM EDT Thu Sep 29 2016

.SYNOPSIS...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Shaved away northern swath of counties from Flood Watch at this
time...as overnight and morning amounts of one to a little over 2
inches fell in these areas and additional amounts should not bring
a threat for flooding.

Farther south, the 2.5 to 3.5 inch amounts that occurred across
the southern tier make those areas suceptible to any persistent
upslope or convective showers over the next 24 hours which could
add another 1 to as much as 2 inches in some spots. Therefore the
Flood Watch is being continued there.

...Previous discussion...

Dry slot with high clouds peeling off to the east spells
transition to low topped open cellular activity propagating from
southeast to northwest today...a more showery regime 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. Strong upslope
flow still moderate PW transport along with some elevated
instability will maintain a favorable environment for heavy
rain/efficient rainfall processes through this afternoon, while
increasingly diffluent flow aloft supports some training bands in
addition to the trend to low topped open cellular character. As
the upper low settles a little further south, backing flow should
shift the heavy rain focus back toward the upslope regions of the
Laurel Highlands this afternoon into tonight.

Still expecting 2-4" over the remaining flood watch area with
locally 5"+ possible aloing 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.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
The upper low continues to double back to MI on Friday before
slowly tracking eastward into the Lower Great Lakes over the
weekend. 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 could possibly increase rainfall rates and amounts through
Central PA as it is coupled with the LLJ and the PWATS.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
The trend for early next week is toward dry weather as the
stubborn upper low is finally is kicked to the northeast by
upstream amplifying trough over the Nation`s mid section. High
pressure should regain control of the large scale pattern. FWIW
the 29/00z GFS is much faster vs. the ECMWF with the projected
path of TC Matthew, with the system nearing the NC coast by
Thursday morning.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Increasingly moist easterly flow will will produce low cigs and
rain across central Pa today. Model soundings and latest SREF
output support predominantly IFR cigs through this evening at the
higher terrain airfields, including KBFD, KUNV, KAOO and KJST. At
the lower elevation airfields, predominantly MVFR cigs are
expected today at KIPT, KMDT and KLNS. However, periodic IFR is
likely this morning associated with bouts of heavier rain.

Outlook...

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

Sun...AM low cigs possible.

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

&&

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

&&

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