Area Forecast Discussion
Issued by NWS State College, PA-- Remove Highlighting --
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FXUS61 KCTP 201837
Area Forecast Discussion
National Weather Service State College PA
237 PM EDT WED JUL 20 2016
High pressure over the eastern Great Lakes will build southeast
across Pennsylvania through tonight, and then off the Mid
Atlantic coast Thursday and Friday. Pennsylvania will be on the
northern edge of a subtropical ridge through next weekend with
shortwave passages likely Friday and Monday.
.NEAR TERM /THURSDAY/...
Mostly sunny conditions prevailing at mid afternoon with low
humidity thanks to 1026 mb sfc high moving east of Lake Erie.
Cirrus streaks streaming from the eastern GLAKS barely dimming the
abundant sunshine for what will be a great late summer afternoon
Similar to last night...skies will be mostly clear tonight and
with anomalously low PW and boundary layer moisture...it will cool
off nicely again after dark. We won`t see the lower 40s that
occurred over parts of the northwest mountains...but mins will
range from around 50F northwest to the lower 60s southeast. Winds
will be light to calm.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
High pressure will have crossed the commonwealth overnight...and
will move off the Mid Atl coast Thursday...allowing return sw
flow to advect warmer and more humid air into the state starting
Friday afternoon. Large scale subsidence and still low pwats
should ensure another dry day with abundant sunshine. GEFS mean 8h
temps arnd 18C should translate to max temps from the m80s ovr the
high terrain, to near 90F in the valleys.
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Big story in the extended fcst is expected heat wave Friday into
early next week, as axis of subtropical ridge shifts from the
plains to the northeast conus. Passage of a weak cold front will
likely produce sct convection Friday pm. However, parent shortwave
is progged to pass well north of Pa, so only sct pm convection
expected, primarily over northern Pa. Behind this feature, 00Z
GEFS indicates anomalous upper lvl ridging building ovr Pa, which
should bring hot wx and suppress convection. Increasing humidity
could spawn widely sct diurnal tsra on Sunday, mainly across the
Alleghenies. A better chance of shra/tsra comes Monday ahead of
next shortwave working across the Grt Lks.
Latest ECENS/NAEFS mean 8h temps are near 20C Friday through
Monday, indicating the potential of several days in a row with
highs in the 90s in the valleys. Heat indices aoa 100F appear
possible by Sun/Mon across the Susq Valley, as higher dewpoints
are advected into the area.
.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions will prevail through Thursday.
Increasing humidity levels on Friday could result in an isolated
shower or thunderstorm, mainly across northern sections of the
The weekend looks to be mainly dry and hot. Some haze and fog
could occur each morning.
Thu...No sig wx.
Fri...Isolated thunderstorm impacts possible.
Sat...Patchy fog possible early...otherwise no sig wx.
Sun...Patchy fog possible early...otherwise No sig wx.
Mon...Restrictions possible with chance of shra/tsra.