Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
946 PM EDT Thursday Aug 27 2015
an unseasonably strong upper trough will finally lift out ot the
east of the region by Friday. High pressure will then build in and
slowly drift off the East Coast over the weekend. Much warmer
temperatures will move into region for the weekend...and very warm
and increasingly humid weather will continue into the middle of
Near term /until 6 am Friday morning/...
infrared loop at 01z shows a narrow band of lingering stratocu across
central PA from kjst to kipt. However...satellite trends and latest near
term model guidance both suggest all area will become clear by
midnight as blyr cools/stabilizes.
Clear skies and a nearly calm wind will result in steadily falling
temperatures overnight a near certainty of locally dense valley fog
across the alleghenies and central valleys. Dewpoint depression already
fairly low at 01z and suspect fog will develop between 04z-06z. Blend
of latest guidance supports min temperatures from the m40s in the coolest
valleys of the northwest...to the u50s in urban areas of the lower susq
Short term /6 am Friday morning through 6 PM Friday/...
Friday will begin our warm up as heights aloft begin to build.
After some early morning fog...skies will become partly to mostly
sunny. Model 800 mb temperatures support highs from the 70s over most of central
PA...to the l80s across the lower susq valley...some 5-8 degree
warmer than today.
Long term /Friday night through Thursday/...
central PA will be on the western edge of a surface high this
weekend...resulting in southwesterly flow and the return of
warmer...more humid air to the region.
A weak disturbance at the surface and aloft will approach from the
Ohio Valley late Sunday...and should weaken as it moves east...but
could bring some showers and isolated thunderstorms Sunday evening
into Monday...mainly across the northern and western mountains.
Models continue to show a large upper level ridge building over the
eastern U.S. Early next week. This will cause temperatures to stay
above normal through at least midweek. It should also keep central
PA mainly dry...excluding isolated diurnal showers and thunderstorms.
Aviation /02z Friday through Tuesday/...
widespread ceilings in the 4000-6000' range will scatter out this
evening with the loss of heating. The clear skies and light winds
will lead to areas of fog and low clouds to form later tonight.
Expect widespread MVFR with local VFR late tonight and at sun up
Friday. Conditions will improve quickly Friday morning as the fog
Burns off to a VFR afternoon.
Thu-Sat...no sig weather expected.
Sun-Mon...mainly VFR with a shower/thunderstorm possible.
Tuesday...no sig weather expected.
short term...Fitzgerald/la corte