Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 232237 AFDCTP Area Forecast Discussion National Weather Service State College PA 637 PM EDT MON MAY 23 2016 .SYNOPSIS... The slow moving storm system that brought rainy cool weather all weekend will slowly edge away from the region today and Tuesday. A noticeably warmer and more summer-like pattern is forecast from mid week into the holiday weekend. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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Showers and isolated thunderstorms slowly diminishing across southern half of central PA this evening. Cyclonic circulation and low heights around offshore upper low circulation created rare NE to SW storm tracks this evening...with one prolific hail producer in Lancaster/York Counties. Red Lion saw the ground whitened by 4-5 minutes of pea to nickle sized hail. Very weak environmental winds but southwest propogating cold pools produced local 30+ mph wind gusts with isolated tree damage...and an already delapidated structure in Lancaster County was further damaged. HRRR continues the current trend of the regional radar mosaic in dissipating showers completely by late evening. Most areas will clear out overnight. In areas of rain this afternoon..increased chance of patchy valley fog.
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Tuesday looks to be a generally good day. Low probability of precipitation. Mostly sunny day.
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&& .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... Extended guidance continues the idea the development of an eastern ridge/western trough pattern, bringing the arrival of the first extended period of summer-like temperatures and humidity. By Wednesday... central PA will be under rising heights as the low lifts out and the ridge bulges east. At the same time a weakening back door cold front will be sliding out of Canada into the rising heights aloft. The models use this to develop scattered showers and thunderstorms Wed afternoon and evening. Precip confidence is never terribly high with surface fronts moving into ridges aloft. By Thursday we will be embedded in a broad wsw flow aloft. Slightly above normal PWATS support the idea that humidity will become noticeable over most of the area for the first time this warm season. It also means we will be susceptible to mainly afternoon convection pretty much on a daily basis into the weekend. The limiting factor will be the eventual sharpness of the upper ridge and how warm we manage to get aloft. The GFS is very aggressive poking the Bermuda ridge strongly up over the eastern U.S. Saturday while the ECMWF is a little flatter. The NAEFS is more in line with the GFS which hints that Saturday could be the day with smallest convective chances. I don`t have anything more than chance pops in the extended given the muddy nature of the ridge and low confidence that it will be able to shield us from upstream convection that will be embedded in the flow. The highest confidence part of the forecast is for temperatures to be above normal through the end of the month. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... Sct shra/tsra across the southern half of Pa will dissipate with loss of heating this evening. A brief vis reduction remains possible thru arnd 01Z across the southern airfields. Focus for late tonight will shift to the possibility of patchy fog, mainly where rain fell during the aftn/evening hours. Both the 15Z SREF and 18Z downscaled NAM indicate this potential of patchy fog across southern Pa late tonight and early Tue am. Widespread VFR conds expected Tuesday, as a ridge of high pressure builds in from the west. OUTLOOK...Tuesday-Friday 5/24-5/27 Tue-Wed...VFR/No sig wx expected. Thu-Fri...Chance of mainly P.M. showers/tstms. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...Grumm/DeVoir SHORT TERM...Grumm LONG TERM...RXR AVIATION...Grumm/Fitzgerald is the U.S. government's official web portal to all federal, state and local government web resources and services.