Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
125 am EDT Thursday may 28 2015
high pressure at the surface and aloft will remain anchored just off
the East Coast through the end of this week. A cold front will
likely push across the region Saturday night or Sunday...then
stall just south of the state early next week.
Near term /until 7 am this morning/...
regional radar at 05z showing a batch of rain showers/thunderstorms and rain lined up along
ll jet/axis of anomalous precipitable waters from central Ohio into western New York.
Best lg scale forcing is prognosticated to lift north of the area this
morning west/parent shortwave and latest hrrr/NAM support the idea of
this band of rain showers rapidliy diminishing between 06z-09z as it moves
through north central PA. Surface cold front...located on the North Shore of
Lake Erie at 05z...will push into the northwest mountains between 10z-12z. The
cooler/drier air behind this boundary won't arrive soon enough to
affect overnight temperatures...which will remain at summerlike levels.
Temperatures on track to bottom out from around 60f over the northwest mountains...to
the m60s across the southeast counties.
Short term /7 am this morning through 6 PM Friday/...
a weak cold front will be the focus for possible isolated rain showers/thunderstorms and rain
across southern PA on Thursday. Otherwise...expect fair and less
humid conds...as northwest flow in wake of front advects a lower precipitable water air
mass into PA. Under mostly sunny skies...ens mean 800 mb temperatures are
supportive of maximum temperatures from the u70s northwest mountains...to the M/u80s
across the lower susq valley.
Long term /Friday night through Wednesday/...
after a brief respite from the humidity Thursday/Thursday night...medium range
guidance signals a return to summerlike weather Friday/Saturday...with
12z gefs showing anomalous 500mb heights and surface pressure off the East
Coast. Developing southerly flow will draw an increasingly
humid/unstable air mass into the area Friday...which may support
scattered diurnally- driven PM convection. However...a better chance of
rain showers/thunderstorms and rain comes late Saturday with approach of a cold front. Some
model timing issues with how fast cold front pushes through Sat
night/Sunday. However...fairly strong signal from all model data
that the first couple days of June /Mon and Tuesday/ will be cool and
perhaps showery...with front stalling out south of PA and
potential of overrunning rain/showers. Have decreased probability of precipitation Friday
night into Saturday...and increased them due to the streaming of
moisture out ahead of the front Saturday night into Sunday. As the
boundary will stall along the southern half of the state have
increased probability of precipitation accordingly.
Aviation /05z Thursday through Monday/...
a Summer-time pattern will continue through the week.
VFR conditions will again give way to some fog overnight...especially in
areas that received rain this afternoon /mainly east/. An area of
mainly rain with a few embedded thunderstorms will work into the northwest mountains
and bring restrictions to kbfd through 07z...but should see a
notable weakening trend in this activity as it erodes away as it
moves eastward. A few renegade showers can/T be ruled out
elsewhere...but probability too low to mention in tafs.
As sunrise approaches...should see some areas of MVFR ceilings develop
again. But these will lift fairly quickly on Thursday as weak cool
front pushes across County Warning Area. VFR day in store for most locales
Thursday...but scattered thunderstorms still poss in the lower susq...mainly in the
Thu-Fri...patchy MVFR fog/ceilings early. Isolated afternoon thunderstorms.
Sat...patchy MVFR fog/ceilings early. Scattered-numerous afternoon thunderstorms west/cold
Sun...MVFR ceilings poss northwest. Otherwise mainly VFR in scattered showers.
Monday...low ceilings likely with chance showers/tstms.