Area Forecast Discussion
Issued by NWS State College, PA

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637 FXUS61 KCTP 230946 AFDCTP Area Forecast Discussion National Weather Service State College PA 546 AM 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 /THROUGH TONIGHT/... Classic rule of thumb calls for fog after it rains during the day and skies clear at night with light winds, and that`s what we are seeing in many locations tonight. We issued a Dense Fog Advisory for the next few hours mainly over central and northern areas. Model agreement is good with respect to the upper low bottoming out around Cape Hatteras today, with the cyclonic circulation growing to influence the pattern from New England down to the Carolinas. Daytime heating and cool temperatures aloft will conspire to steepen lapse rates and help support scattered showers and thunderstorms later this morning into the afternoon. Capes are not expected to be very impressive and shear will be meager so the anticipation is for pulse thunderstorm development. HIRES deterministic and ensemble blend favors the southern 1/2-2/3 of the area for the best chance of additional rain through 24/00z followed by a decreasing/drying trend into the overnight. Maximum temperatures will rebound into the upper 60s and low 70s which is near to slightly below normal with the largest departures on the order of about 5 degrees across southern PA. The chances for rain will shrink steadily overnight, but with the edge of the cyclonic circulation associated with the upper low still slopping over eastern Pa, the chances for a shower never go to zero over my far eastern zones. Lows will range from the mid 40s north to mid 50s south, which will be near to even a little above normal in most locations. && .SHORT TERM /TUESDAY/... Highs Tuesday will rise into the lower 70s over higher elevations of the west and north, and in the mid to upper 70s elsewhere. Other than a small chance for a lingering shower east, still on the outer edge of the amazing late spring upper low, most areas will be bright and dry as the warming trend really gets under way. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... 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 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 /10Z MONDAY THROUGH FRIDAY/...
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As of 5 am...sites that saw some clearing quickly had dense fog form. Expect the fog to burn off by 12Z...given the mid May sun angle and that most sites still have light breeze. Given the cold air aloft...there could be a few showers around the area...perhaps a rumble of thunder. VCTS in the TAFS. Skies clear out tonight again. OUTLOOK...Tuesday-Friday 5/24-5/27 Tue-Wed...VFR/No sig wx expected. Thu-Fri...Chance of mainly P.M. showers/tstms.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 8 AM EDT this morning for PAZ004>006- 010>012-017>019-024>028-033>037-041-042-045-046-049>053- 056>059-063. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...La Corte LONG TERM...La Corte AVIATION...Martin is the U.S. government's official web portal to all federal, state and local government web resources and services.