Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 200638 AFDCTP Area Forecast Discussion National Weather Service State College PA 238 AM EDT Wed Sep 20 2017 .SYNOPSIS... A ridge of high pressure at the surface and aloft will stay locked in place over Pennsylvania for the next 7 days. This dominant weather feature will provide fair, warm and generally dry weather throughout this entire period. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Skies remain mostly clear late this evening across all but extreme eastern portions of central PA this evening. The western extent of clouds continue to brush my SE zones and will keep bkn- ovc skies going overnight. Have removed shower mentions for the overnight as well. Clouds associated with a weakening frontal boundary will dissipate over far western PA overnight, and the low level flow becomes light and northerly later tonight as Jose weakens to a Tropical Storm and continues to slowly drift off in a northeast direction. This will transition us away from the stratus we saw this morning back to locally dense valley fog for Wednesday morning. Min temps will be about 2-4F lower than early Tuesday over the northern half and similar to Tuesday for the southern half - and notably milder than normal. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... After we burn off the fog in the valleys, a spectacular Wednesday is on tap with abundant sunshine and just a few flat cu and thin cirrus to paint the otherwise azure blue sky. Could be a couple of showers off to our SW in a very weak and eroding trough, but only result for us will be potentially an increase in cloud cover over the Laurel Highlands. Max temps will once again range from the upper 70s across the higher terrain of the north and west, to the lower 80s (and maybe a few mid 80s) in the southeast. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Overall pattern hasn`t changed much, there is a good overall consensus in the models through the second half of the work week. For much of this period, a 590 dam closed 500 hPa high will drift slowly out of the midwest states, and become centered over western PA by late this weekend through early next week. The GEFS forecasts showed this feature as a closed 5880 m ridge over us with near +2 sigma above normal heights which will translate to well above normal temperatures. High temps from Wednesday and through the weekend will be 10-15F above normal with little or no chance of rain through at least Monday. Lows early each morning will be consistently in the mid and upper 50s across the northern and western mtns, to lower 60s in the larger SE metro areas. Min temps may cool off slightly for this weekend thanks to deep dry air and a light N to NW llvl flow of drier dewpoint air at the sfc. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... GOES-16 fog channel imagery shows widespread valley fog confined to the west of the Susquehanna River. The outer edge of cloud shield associated with TS Jose is drifting over the southeast airfields and should preclude fog formation. Fog will be locally dense with restrictions AOB airfield minimums. Expect fog to dissipate through mid morning with VFR conditions this afternoon and evening. .Outlook... Thu-Sun...Patchy valley fog possible each morning. Otherwise VFR with generally light winds and minimal clouds. && .CLIMATE... Astronomical Fall/Autumnal Equinox begins at 4:02 PM Friday September 22, 2017. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert/RXR NEAR TERM...DeVoir/RXR SHORT TERM...RXR LONG TERM...Ceru/Gartner AVIATION...Steinbugl CLIMATE...Steinbugl

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