Area Forecast Discussion
Issued by NWS State College, PA-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KCTP 280000
Area Forecast Discussion
National Weather Service State College PA
800 PM EDT SAT AUG 27 2016
A large ridge of high pressure will reside over Pennsylvania
through midday Sunday bringing very warm and mainly dry weather.
A weak cold front will push southeast across the state Sunday
night into Monday morning. Scattered showers and thunderstorms are
possible ahead of the front. Another period of warmer than normal
and mainly dry days will follow for Monday into at least early
.NEAR TERM /THROUGH SUNDAY/...
Just some high clouds now. There was a few CU earlier.
Been watching a cluster of showers and storms moving
northward, but these look like they would stay west
of central PA this evening. Another area over Lake
Erie. The airmass over central PA not real moist, and
with the sun setting, expect the evening to remain dry.
Forecast temperatures look good still.
Earlier discussion below.
Strong ridge over the Mid Atlantic with 594 heights through
Central PA will continue into Sunday. Skies should be mainly clear
tonight. Dew points in the northern mountains still in the upper
50s to lower 60s so another comfortable night in the north. Temps
and dew points will converge around the mid 60s by morning in the
lower Susq Valley. Some low clouds or light fog may possibly form.
.SHORT TERM /SUNDAY NIGHT THROUGH 6 PM SUNDAY/...
Will have to monitor the situation on Sunday. At this point, very
warm air aloft during the day on Sunday may make it hard to fire
up many showers or storms. Cooling aloft later Sunday night into
Monday might lead to a better chance for showers and storms.
Earlier discussion below.
A weak cold front will bring the chance for showers or
thunderstorms later Sunday afternoon/evening - mainly over
northern and western sections of the state. Weighted our previous
fcst POPs to the latest run of the Superblend. Little or no chc
for precip across the far SE zones remains.
SPC has placed the NW third of our CWA in a Marginal Risk for
severe Sunday afternoon and evening...which looks pretty good
based on moderate, westerly deep-layer shear and a SW-NE ribbon
of rather impressive MU cape of 2500-3500 j/kg extending from
near KELZ and KBFD...to KBTP.
Gusty (and highly localized damaging) westerly winds will
accompany the storms in the 18Z Sunday - 01Z Monday period in the
MRGL Risk area.
Above normal temps will continue on Sunday with similar maxes (or
perhaps just a few deg f lower than Sat`s across the Susq Valley).
Highs expected to range from the mid 80s (mtns) to near 90F in the
Lower Susq Valley.
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
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
A weakening cold front will push slowly SE through the
Commonwealth Sunday night into Monday morning accompanied by
isolated to scattered showers/thunderstorms. The frontal
boundary is expected to wash out near or just south of the
Mason/Dixon line during the day Monday. Abundant low-level
moisture, mesoscale convergence and some orographic lift/heating
via the east to NE low level flow regime across the mountains of
SW PA will focus the best chance for showers and scattered
thunderstorms there Monday afternoon.
Monday night through Wed morning looks to be dry with generally
light wind and just the possibility of patchy early morning valley
Medium range guidance agrees with a second-stronger cold front
pushing SE across the area Wednesday afternoon or early Thursday,
with a renewed chance for showers and thunderstorms.
This front will be followed by a cool-down for the end of next
week. 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.
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --Mainly VFR conds and light wind expected through Sunday, as high
pressure ridge remains in place across eastern Pa. Some patchy fog
could reduce vsbys in a few spots early Sunday morning. At this
point, significant reductions appear unlikely, but can`t
completely rule out a brief period of IFR in the vicinity of
KUNV, where sfc obs and near term models are pooling an area of
enhanced low level moisture.
The other potential threat to aviation will be sct tsra developing
across northwest Pa during the afternoon in advance of an
approaching cold front over the Great Lakes. The best chance of a
brief tsra impact would be at KBFD, however potential could extend
into the KJST/KUNV/KIPT corridor by early evening.
Mon...AM fog poss, mainly KBFD. Isold PM tsra impacts poss south.
Tue...AM fog poss, mainly KBFD.
Wed...Isold PM tsra impacts possible.
Thu...No sig wx expected.
-- End Changed Discussion --
LONG TERM...La Corte