Area Forecast Discussion
Issued by NWS State College, PA

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440
FXUS61 KCTP 281808
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
208 PM EDT SUN AUG 28 2016

.SYNOPSIS...

A weak cold front will sag slowly south tonight and Monday
morning. High pressure will bring another period of warmer than
normal and mainly dry weather for Monday into Wednesday. A
cold front will move across the commonwealth Wednesday followed
by a refreshingly cooler airmass with low humidity Thursday
through Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...

Spotty convection has finally started to pop over the western
higher terrain in an axis of deep moisture and mixed layer Capes
in the 1500-2000J range. So far warm mid levels and weak lapse
rates have provided an effective lid, but slowly falling upper
heights/temps with the approach of a weak mid level shortwave
should help steepen lapse rates and provide more support for
convection as we enter the late afternoon and early evening.

Latest HRRR lights up a NE-SW band over the north-central part of
the forecast area and doesn`t move it very far very fast. it just
sort of sags it slowly south while weakening later in the
evening. The NCAR ensemble does something similar, showing just a
slow settling south in time of eventual convective developments.

Above normal temps will continue today with highs expected to
range from the mid 80s (mtns) to near 90F in the Lower Susq
Valley.

Guidance suggests little if any shower activity lingering past the
midnight hour so the forecast shows things drying out later in the
evening with much of the overnight remaining dry.

Lows generally in the 60s will average some 10-15 deg above
normal.

&&

.SHORT TERM /MONDAY/...

The weak cold front will stall along or just south of the Mason/Dixon
Line Monday afternoon providing the low level convergence to help
focus what will be mainly scattered convection during the
afternoon over southern PA.

High temps Monday will vary from near 80 across the NW Mountains
to around 90 in the southern valleys.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
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.

A weakening cold front will push slowly SE through the
Commonwealth tonight and early Monday 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
fog.

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 /18Z SUNDAY THROUGH FRIDAY/...

All terminals are VFR as of late morning and will continue into
the afternoon and evening hours.

Scattered thunderstorms will cause brief local restrictions late
today into the evening hours over the NW 1/2 of the airspace ahead
of a weak boundary pushing out of the the Lower Great Lakes. Light
winds and high boundary layer moisture could result in some low
ceilings and fog after midnight into early Monday morning.

Outlook...

Mon...VFR. Isold PM TS possible southern Pa.

Tue...Patchy AM fog, then VFR.

Wed...Sct PM TS impacts possible.

Thu-Fri...No sig wx expected.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...La Corte
NEAR TERM...La Corte
SHORT TERM...La Corte
LONG TERM...La Corte/Lambert
AVIATION...La Corte



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