Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 160748

Area Forecast Discussion
National Weather Service State College PA
348 AM EDT Sun May 16 2021

A brief thundershower will be possible in spots during the
afternoon and evening Sunday and Monday. A pattern change
toward summerlike conditions will bring mainly dry weather and
much warmer/above normal temperatures to Central PA through next


H5 shortwave is progged to track east-southeast across the
region today. Combination of large scale forcing and weak
diurnal instability will promote a gradual uptick in scattered
convection from late morning into the evening. Although not a
washout, more clouds than sun will result in a cooler day with
maxT trending below climo and 2 to 6 degrees lower than
yesterday. Shower activity will fade into the evening and
diminish by late tonight. Cloud cover will range from partly to
mostly cloudy tonight with minT trending warmer.


A weaker shortwave is progged to track southeast across PA on
Monday. Can`t rule out a stray afternoon thundershower, but
surface ridging and relatively low pwats favor rain-free
conditions  over the vast majority of the area. MaxT will trend
warmer to within a few degrees of mid-May climo with highs in
the upper 60s to low 70s.

Building upper level ridge over the Eastern U.S. will mark the
beginning of a pattern change toward summerlike conditions
starting on Tuesday. We were keen to front-run this shift by
incrementally adding a few degrees to MaxT, pushing highs to
around 80F southeast of the higher terrain.


All medium range guidance supports a building upper level ridge,
centered over the Ohio Valley/Eastern Grt Lks, later next week.
Surface high shifting off of the east coast and ensuing
southwest flow will advect progressively warmer and more humid
air into the state, with ensemble plumes supporting well above
normal temperatures the second half of the week. ECENS and GEFS
mean 850mb temps rise to around 15C the second half of of next
week, which would support highs in the 80s over all but the
highest terrain.

Warm temps aloft may largely suppress PM convection Wed-Fri.
Some model spread by next weekend, but the 12Z ECENS supports a
better chance of convection by Saturday, as upper ridge axis
shift west, placing Pa in ring of fire on northeast periphery of
upper ridge.


Good VFR continues early Sunday morning as an area of mid cloud
moves east across the state. Any ceilings will remain at or
above FL100 with light to calm winds.

Expect this mid cloud layer to continue through the day with the
possibility of a -SHRA or -TSRA during the afternoon hours.
Coverage would be limited so continued VCSH wording for that
time frame.

By 17/00Z, any -SHRA will have diminished and a return to a BKN
layer remains through the end of the forecast period.


Mon...Predominantly VFR. A few aftn -SHRA are poss.

Tue-Thu...Generally VFR.




NEAR TERM...Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Fitzgerald
AVIATION...Evanego/Tyburski is the U.S. government's official web portal to all federal, state and local government web resources and services.