Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 300536 AFDCTP Area Forecast Discussion National Weather Service State College PA 136 AM EDT SAT JUL 30 2016 .SYNOPSIS... An upper level trough will influence the region through early next week...bringing daily chances of scattered showers and thunderstorms. Most of the time will be dry in any one location however. high pressure will build over the northeastern united states by mid to late next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Dying cold front pushing into central Pa this evening, producing enough lift to support isold showers across the central and southern counties late this evening. Latest CAMS indicate focus for dwindling convection will shift into the southern counties late this evening, then die out as blyr cools/stabilizes. Focus will then shift toward shortwave approaching from the Grt Lks. Latest guidance supports an increasing chc of showers assoc with this feature ovr the western counties arnd dawn. Low tonight mainly in the 60s some warmer spots in southeast and cooler in northwest. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... Most guidance continues to show the plume of high PW air coming into PA Saturday ahead of approaching shortwave. This favors an increasing chance of showers and thunderstorms as the day wears on. The GEFS 0.5 degree data implies the chance of rain increases rapidly after 11 AM Saturday and keeps climbing. It of course has a big wet bias in convective cases. The GEFS and all the blends imply lowest PoPs in northwest and west and higher central to eastern areas. GEFS is basically showing rain over all of eastern and central PA by 21Z. Expect showers and thunderstorms with areas affected by intense cores to see some better rainfall amounts by late in the day. Both 12Z SSEO and earlier 00Z NCAR ensemble output supports fairly widespread rainfall amts of arnd 0.5 inches by 00Z Sunday, with localized amts ovr 1 inch. The rainfall peaks in the SREF/GEFS shortly after the CAPE peaks. This implies mostly convective and CPS is biasing forecasts. The most intense rainfall is forecast mainly after 21Z and early overnight Saturday which is mainly in the next forecast period. Mainly cloudy skies and widespread convection should hold temps down Saturday to the u70s and l80s. However, humidity will be high with dwpts likely close to 70F. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Shortwave moves across PA Saturday night triggering showers and possibly a thunderstorm. As that passes to the east, there should be a break and then the main trough moves through with some scattered convection likely late Sunday and Sunday night. Do not believe it will be as wet as earlier advertised by models. Diminishing POPs into Monday as the upper level trough and cyclonic flow slowly exits off the coast. Big ridge builds over the central US and moves east to Ohio by Friday. This puts us into a drier pattern with NW flow. May see something move over the ridge but then drop to the west and south of PA. Can`t rule out some afternoon clouds popping and maybe an isolated convective cell over the higher terrain but that should be it. Temperatures will start out in the normal range and warm to above normal toward the end of the week. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... Few showers still north and west of MDT as of 130 AM. 06Z TAF package looked good. TAFS sent. Earlier discussion below. VFR conditions exist at all airfields, yet there may be some local restrictions in the widely scattered shower activity that still lingers over the Lower Susquehanna Valley. Expect convection to continue to trend downward in coverage during the overnight...pretty much contained to the same area. Expecting widespread MVFR conditions to develop overnight in fog, with some patchy IFR conditions especially where any of the spotty rain fell today. Showers and thunderstorms increase across the region tomorrow. Model guidance implies restrictions in visibilities for much of the area during the afteroon tomorrow. Have kept with this thinking, with visibilities 5 or 6 miles in most areas, and prevailing SHRA in all TAFs. Included VCTS as will in all TAF locations beginning between 19z and 21z. Rain and thunderstorms taper off Saturday overnight, but should be plenty of fog around with widespread restrictions. Scattered showers and thunderstorms remain through Monday, then generally VFR from Tuesday onward, except for patchy fog. OUTLOOK... SAT...Morning fog, then SHRA/TSRA with more restrictions during the day. SUN-MON...Morning fog restrictions, then scattered showers and isolated thunder. TUE-WED...Mainly VFR, but with morning fog restrictions. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...DeVoir/Fitzgerald NEAR TERM...Fitzgerald SHORT TERM...Grumm/Fitzgerald LONG TERM...Watson AVIATION...Jung/Martin is the U.S. government's official web portal to all federal, state and local government web resources and services.