Area Forecast Discussion
Issued by NWS State College, PA

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558 FXUS61 KCTP 291604 AFDCTP Area Forecast Discussion National Weather Service State College PA 1204 PM EDT Sat Apr 29 2017 .SYNOPSIS...
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A nearly stationary frontal boundary will remain over the forecast area for much of the weekend. A strong trough and cold front will move across the region on Monday, followed by much cooler temperatures.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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The first area of decaying convection has almost exited my eastern zones. The leading edge of a new MCS is already on the PA-OH border and is streaking east. Unstable air as measured by CAPE is pretty much confined to the Mason-Dixon line southward, but RAP analysis indicates mid level lapse rates are a fairly respectable 7C/km or higher. The HRRR survives these showers as they move into central PA from about noon through late afternoon, with the northern 2/3 or so of the region standing the highest chance of getting wet. The frontal system over PA is hard to find in the meso anal but the more humid air over the south seems to be separated by a boundary that extends from near PIT eastward to between AOO and UNV then northeastward. Satellite loop indicates that much of the mid and high cloud debris from the earlier convection is moving over eastern PA but leaving much of the lower clouds east of the mountains in place. A cirrus canopy is expanding quickly out of OH so prospects for significant brightening are...dim. Temperatures are still on track to top 70 over most of the southern half of the region, with cooler 60s dominating along the northern border.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... 29/06Z NAM guidance brings both of the previously noted frontal boundaries gradually back to the north overnight and Sunday, but maintains shallow chilly air across the Central and NE zones as the elongated east/west 1022-1026 mb sfc ridge slides over the middle St Lawrence River Valley by Sunday afternoon. Again, the main focus for Sunday may be periods of heavy rain showers/TSRA from elevated convection, while any sfc-based updrafts stay limited to the south central counties and wrn mtns near and to the west of RT 219. Sunday`s max temps will also be weighted more heavily twd the cooler 29/06Z NAM with a 25 percent NBM blend afterward, which will lead to highs in the mid to upper 70s over the west and south, and only low-mid 60s in the far NE and wrn Poconos. With dewpoints well up into the 60s over far southern and western portions of the CWA, it will begin to feel humid. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Upper level ridge builds across the Mid Atl Region Sunday night and Monday and a warm front will be lifting through the Ohio Valley and W PA. This weather feature will lead to continued chances for showers and even a tsra - mainly in the NW half of the area. Temps should return/rise to very very warm levels on Monday. A massive and deepening cyclone lifting into the western Great Lakes Sun night into Monday will push a strong cold front through PA Mon into Mon night, accompanied by a round of potentially potent showers and thunderstorms (likely reaching western half of CWA in the afternoon and eastern half during the evening). Once this front passes by much chillier air will advect into PA on cyclonic flow with unsettled light showery weather persisting mainly for the northern part of the state right into Wednesday. Chance for a more widespread light rain arrives Thu into Fri as a low progged to develop along the southern Appalachians and lift northward. Models showing strength/timing issues so not getting to specific this far out, but looks like unsettled weather pattern continues. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
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Most terminals are and will remain VFR until the next area of showers/embedded thunderstorms moves into the region, reaching JST-AOO by early afternoon and spreading east through mid to late afternoon. The showers and thunderstorms will bring local reductions to MVFR or lower into the overnight. Outlook... Sun...Sct showers/Tstorms with sub-VFR restrictions possible especially over the west-central airspace. Mon...Breezy. Showers/thunderstorms likely with periods of sub- VFR. FROPA. Tue-Wed...Breezy with a chance of showers NW 1/2.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte/Lambert NEAR TERM...La Corte/Lambert SHORT TERM...Lambert LONG TERM...Lambert/RXR AVIATION...La Corte/Steinbugl

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