Area Forecast Discussion
Issued by NWS State College, PA

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281 FXUS61 KCTP 231527 AFDCTP Area Forecast Discussion National Weather Service State College PA 1127 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/... We still have a few areas of low clouds to burn off in some of the river valleys. But most of the fog has burned off and many areas are mostly sunny with only patchy high clouds. We are now on the western side of the upper low. Most of the widespread rain is to our east. The SREF, GEFS, and HRRR all imply the potential from 2 PM until at least 5 PM of showers and thunderstorms developing from central areas to the east. QPF is very light and it could be hit or miss. Any showers will be instability driven and should diminish during the evening hours. && .SHORT TERM /TUESDAY/... Overnight Monday into Tuesday will have light surface flow so some potential for overnight fog in the valleys again. The flow aloft becomes more anticyclonic and weakly anticyclonic at the surface. Thus all the guidance is warm with 10 to 14C range. Should be a mostly sunny dry day with temperatures mainly in the 70s. && .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 /16Z MONDAY THROUGH FRIDAY/...
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VFR is the rule this morning over the region and should remain so into this afternoon. Satellite and radar show mostly clear skies some patches of high clouds. The flow is from the northeast today. The short-term models still show some bands of showers developing over central and eastern areas. Not a lot of organization. With the upper-level low to our east these will be more hit or miss. Kept VCTS in TAFS in southern and eastern areas. The 3km HRRR implies best chance of rain/thunder is after 18Z today and highest probabilities would imply KMDT and KLNS. Basically, from KSEG south has best probabilities and lower as you move north and west. Most or all activity should diminish before sunset. Mainly VFR overnight perhaps patchy MVFR in some valleys. 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... None. && $$ SYNOPSIS...La Corte NEAR TERM...Grumm/La Corte SHORT TERM...Grumm/La Corte LONG TERM...La Corte AVIATION...Grumm/Martin

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