Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 201440 AFDCTP Area Forecast Discussion National Weather Service State College PA 1040 AM EDT WED JUL 20 2016 .SYNOPSIS... High pressure over the eastern Great Lakes will build southeast across Pennsylvania today, then off the Mid Atlantic coast by late week. Pennsylvania will be on the northern edge of a subtropical ridge through next weekend with shortwave passages likely Friday and Monday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Mostly sunny conditions prevailing at mid morning with low humidity thanks to 1026 mb sfc high centered over Lake Erie. Cirrus streaks streaming from the eastern GLAKS will slightly dim the sun on what is otherwise one of the nicest mid July days we can get. Keeping temps above guidance due to unusually dry ground and boundary layer and nearly full sun. This puts highs from the upper 70s northwest mountains and higher ridges of the Allegheny plateau to the lower to middle 80s central and south.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Clear and tranquil conds expected tonight beneath sfc high with temps dropping several deg blw seasonal norms due to dry air and amount of radiational cooling. As high pressure passes off the Mid Atl coast Thursday, return sw flow will begin advecting warmer, more humid air into the state. 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 /15Z WEDNESDAY THROUGH SUNDAY/...
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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 airspace. The weekend looks to be mainly dry and hot. Some haze and fog could occur each morning. OUTLOOK... 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.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Fitzgerald NEAR TERM...DeVoir/Fitzgerald SHORT TERM...Fitzgerald LONG TERM...Fitzgerald AVIATION...DeVoir/Gartner/Martin is the U.S. government's official web portal to all federal, state and local government web resources and services.