Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service State College PA
1043 PM EDT Wednesday Aug 31 2016

Synopsis...
a cold front will push southeast across the commonwealth
overnight into early Thursday, bringing a chance of showers. A
refreshingly cooler airmass will overspread the region for
Thursday through Saturday.

&&

Near term /until 11 PM this evening/...
shortwave and assoc cold front pushing southeast from the grt lks
will bring scattered showers to the region overnight. Storm Prediction Center mesoanalysis
still showing some marginal instability across York/Lancaster
counties at 02z, so will maintain a slight chance of thunder there
thru arnd midnight. Best chance of showers will accompany passage
of low lvl jet and assoc plume of anomalous pwats, which lies
across the central counties at 02z, but will shift to the lower
susq valley toward dawn. Blend of latest mdl guidance supports
overnight rainfall amts averaging btwn 0.1 and 0.2 inches across
much of central PA, with perhaps a bit more across the lower susq
valley.

Back edge of cloud cover is entering lk Erie at 02z and expect
partial clearing to work into the northwest mtns late tonight. The
clearing skies, combined with light wind, should promote areas of
fog up there early Thursday morning. Lows expected to dip into the
upper 50s across the NW counties, while cloud cover and lingering
low lvl moisture hold readings in the 60s across the rest of
central PA.

&&

Short term /11 PM this evening through 6 PM Thursday/...
although cold front will have cleared the region Thursday, upper
level trough will still be upstream. Model soundings support the
idea of sct-bkn cumulus. Some may grow into taller cu, esp in the
SC mtns, where a minimal chc for a shra will be kept. Gefs mean 8h
temps btwn 10-14c from NW to se should translate to Max temps from
arnd 70f over the northwest mtns, to the low 80s across the susq valley.
The greatest change in dwpts should be felt across the NW
counties, while moderately humid air lingers across the southeast.

&&

Long term /Thursday night through Wednesday/...
cool down will last into the weekend with Max temps mainly in the
70s Fri and Sat over the northern and western higher terrain,
with low to mid 80s elsewhere...as the upper trough deepens over
central Quebec and extends to the mid Atlantic Piedmont. Temps
begin to creep up again late weekend into early next week.

Tropics remain active and despite no impacts anticipated for PA...
interesting evolution of td9 after it slips across Florida into the
Atlantic for sun-Mon. Latest guidance is more progressive with the
storm taking it offshore before displaying a slight westward jog
on Monday...which could brush eastern Long Island or southern New
England if system is that far north. For central PA...it looks
like another prolonged dry and comfortable stretch of weather from
Friday through Monday/Tuesday.

&&

Aviation /03z Thursday through Monday/...
band of mainly light rain falling out of a 10kft deck will
continue to gradually push further south and east into the
overnight hours. Minor accumulations and limited reductions in
flight category are expected from this area of rain - though
isolated convection may bring thunderstorms in the vicinity to the lower susq through
midnight, with showers persisting there prob through the predawn
hours.

Cold frontal boundary initiating the rain will push south of the
state by 12z, but cig/vsby reductions will develop from northwest to southeast
as rain comes to an end overnight, with upslope moist flow
bringing LIFR/IFR cigs in bfd/jst and generally MVFR (with some
ifr) elsewhere.

The clouds should break up/lift through the morning on thurs as
mixing of the drier air occurs. Clouds linger into the late
morning over the higher elevations, and mid morning elsewhere.

High pressure then takes over through Saturday.

Outlook...

Thu afternoon-Sat...am fog possible. Otherwise, no sig wx
expected.

Sat night-sun...showers possible, esp southeast. Cig reductions poss southeast.

Mon...no sig wx.

&&

Ctp watches/warnings/advisories...
none.

&&

$$
Synopsis...dangelo/devoir
near term...Fitzgerald
short term...dangelo/Fitzgerald
long term...rxr
aviation...rxr

National Weather Service Glossary of Abbreviations