Wednesday, August 31, 2016, 2:01 AM EDT
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Area Forecast Discussion
||Wed, Aug 31, 1:15am EDT
FXUS61 KCTP 310515
Area Forecast Discussion
National Weather Service State College PA
115 AM EDT WED AUG 31 2016
A cold front will move across the commonwealth late today through
early Thursday...bringing a chance of showers and thunderstorms. A
refreshingly cooler airmass will overspread the region for Thursday
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
High pressure maintaining fair conditions overnight. Shortwave
moving through Ohio Valley is spreading sct-bkn cirrus into
western and central PA early today...while mostly clear skies
remain across the southeast half of PA.
The cloud cover and a light sw breeze should preclude much fog
formation tonight over the northern counties. However, some patchy
fog does appear possible arnd dawn across the southern counties.
Lows will range from the upper 50s over the Alleghenies to lower
60s across the Susq Valley.
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
Shortwave and assoc sfc cold front moving in from the Grt Lks will
be the focus for showers Wednesday, mainly across the northwest
mountains during the afternoon. Mdl rh fields indicate there will
be a good deal of mid and high level cloudiness across northern
and western Pa, limiting instability and assoc chance of thunder.
However, msunny skies across the southern valleys should push
temps into the upper 80s and result in enough instability to
support the chance of a few late day tstorms across the southern
counties. Latest SREF/GEFS indicating some marginal CAPES across
the south central mtns during the aftn and almost no CAPE elsewhere.
Cloud cover may hold temps to the mid 70s across the northwest
mtns, while 90F is possible in the valleys along the Mason Dixon
line based on progged 850 temps nr 18C.
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The extended period looks like it will feature a transition from a
persistent upper-level ridge over the eastern United States to a
weak upper-level trough by mid to late week. As a result, above-
normal temperatures through the Tuesday-Wednesday timeframe will
transition to near or a little below normal by the end of the period.
Medium range guidance agrees with a second-stronger cold front
pushing SE across the area late Wednesday through Wed night, with a
renewed chance for showers and thunderstorms. Have upped PoPs to
high-end chance with afternoon fcst package.
This front will be followed by a cool-down for the end of next week
and into Saturday. Max temps should be mainly in the 70s Thursday
into the weekend over the northern and western higher terrain, with
low to mid 80s elsewhere as an upper trough amplifies from central
Quebec...to the Mid Atlantic Piedmont. Temps begin to creep up again
late weekend into early next week.
Interesting developments with potential eventual track of TD9
after it slips across FL into the Atlantic. Wed night's
front/trough will have pushed into the Carolinas by then, guiding
TD9 off the Carolina coast on a NE trajectory. But 12z model
guidance (both GFS and ECMWF) hint at a potential bit of a
temporary jog back toward the New England coast Sunday or Monday.
For now, potential impacts to central PA are very low.
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
Widespread VFR will continue overnight before patchy fog once
again develops toward daybreak Wednesday. After the early fog,
Wednesday will see VFR conditions return for most of the day
before scattered mainly afternoon showers and thunderstorms bring
Thu-Sun...No sig wx expected.
SHORT TERM...Fitzgerald/La Corte