Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 280326 AFDCTP Area Forecast Discussion National Weather Service State College PA 1126 PM EDT Thu Apr 27 2017 .SYNOPSIS... A strong subtropical ridge will build westward from the Atlantic Ocean over the weekend. We will be on the warm, moist western side of the ridge most of the weekend. A strong trough should bring cooler drier weather to the region for the second part of next week. && .NEAR TERM /UNTIL 8 AM FRIDAY MORNING/... Trough overhead now, and so is the lightning and briefly torrential rain. But, it is moving very quickly. A ciruculation aloft is kinking what was previously a linear feature of rain/thunder over the western mountains. The front appears to be over KBFD- KAGC and moving eastward. The main problem along the line is a long- lived cell with generally weak rotation but a persistently strong updraft. Will have to watch for it as it nears DuBois in a little over an hour. It has survived through a fairly worked over area for a few hours. Heavy rain is still possible to the NE of KUNV where the rain will ride over the same area for a couple of hours. Prev... Showers and a few low-topped TSRA rolling through the western highlands are already diminishing as they hit the stable air in the central mountains. A second and perhaps third line moving in are closer to the front and real westerly wind behind it. The shortwave trough that has been driving this action is still a few hours from passing. However, this stuff is moving into an area where it has already rained this evening. With loss of daytime heating, and already paltry CAPE to the east of the current TSRA there should be a decrease in both coverage and intensity through midnight. Almost nothing should be left by then. Will mention some fog area-wide despite light west wind as the dewpoints do not look like they will drop too far/fast overnight away from the NW few counties. && .SHORT TERM /8 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... Friday looks like a pretty decent day after a bit of a muggy start in the SE half. Some left over clouds in the morning will probably burn away with mixing and downslope. Maxes will still be about 8-10F above normal. For Friday night a boundary sets up over PA with a few waves rippling along the boundary. There is some uncertainly on how much instability is left over and exactly where this boundary sets up. Some late convection could ride along the top of the ridge and affect the northern counties. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Upper level ridge tries to builds in for Saturday to Sunday but continued southerly flow and instability will lead to additional chances for showers and storms - mainly in the northern half of the area. Temps remain very warm into Monday. Used superblend for this time period. Main feature will be a massive cyclone that tracks through the Western Great Lakes from Sunday night through Monday night. This will push a strong cold front through PA and lead to another round of showers and thunderstorms. Once this feature passes by much chillier air will advect into PA with unsettled weather mainly for the northern part of the state right into Wednesday. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... Other than a storm near IPT, just a few showers to the south. Gusty southeast winds to the south have weaken, thus hard to see anything much reforming across the southeast. Rather dry air working eastward from the west, just above the ground. Main issue now is how much fog and low clouds form overnight. Made a few adjustments on the 03Z TAF package. Expect conditions to quickly improve Friday morning, as the airmass will be quite dry. Outlook... Sat-Sun...A few showers possible. Perhaps a thunderstorm. Mon...Breezy with showers and thunderstorms likely with FROPA. Tue...Mainly VFR. Possible MVFR in shra in BFD. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo NEAR TERM...Dangelo SHORT TERM...Dangelo LONG TERM...BGM AVIATION...Martin

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