Area Forecast Discussion
Issued by NWS State College, PA-- Remove Highlighting --
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FXUS61 KCTP 302140
Area Forecast Discussion
National Weather Service State College PA
540 PM EDT Fri Sep 30 2016
A cut off upper low over the Ohio Valley will slowly drift
northeast over the next several days, clearing the region by early
next week. A ridge of high pressure will build east into
Pennsylvania behind this system and will likely remain over the
area through the end of the work week.
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Evening water vapor loop showing cut off upper low over the Ohio
Valley. Deep, moist easterly flow ahead of this system continues
to produce stratus and areas of drizzle across central Pa as of
21Z. Shortwave rotating up east side of upper low should produce
an increasing chance of measurable rain after midnight. Regional
radar at 21Z shows band of showers over the Virginias and model
data indicates these showers will shift northward overnight with
arrival of shortwave and associated low lvl jet.
Temps already close to dwpts, so expect little change in temps
overnight, with readings holding in the 50s.
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
Another murky day expected across central PA Saturday with low
coverage of showers happening at just about any one time.
Not expecting anything particularly organized or heavy...but the
morning hours could see the most persistent shower activity as
deep layer moisture associated with shortwave lifting northward
over eastern PA brushes my eastern zones..
Following 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...but this is still higher than NBM. 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 FRIDAY/...
Latest operational models track the persistent and slow-moving
cut-off low to near Detroit at 12z Sunday, before it finally
begins to turn east and gradually fills in as it gets picked up in
the longwave flow and tracks across NY state Monday.
The results on the forecast will be a continuation of showery
weather through the weekend, though with just light amounts.
Followed by a slight chance for showers across the north early
next week along with cold air advection filtering into the region
early next week.
Surface high pushing the cooler air our way slides off the New
England coast midweek, but persistent easterly flow feeding into
the Mid-Atlantic region should keep plenty of clouds around along
with at least a chance for light showers/drizzle across southern
half of CWA through midweek.
Latest on Hurricane Matthew in the 12z runs - it generally follows
a similar path to prev runs in the GFS brushing the Carolina before
the storm begins to drift NE and away from the VA/NJ coast (this
generally agrees with NCAR guidance as well). Operational ECMWF
now parks the storm over the Bahamas, which is a low confidence
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.
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --Widespread MVFR-IFR conditions through tonight. Pockets of
Not much change expected before Sunday.
Changes made to 21Z TAFS, which I would be doing shortly
anyway for 00Z TAFS.
Sun...MVFR cigs. Chc -SHRA.
Mon-Tue...Gradual improvement likely.
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