Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 280000 AFDCTP Area Forecast Discussion National Weather Service State College PA 800 PM EDT SAT AUG 27 2016 .SYNOPSIS... A large ridge of high pressure will reside over Pennsylvania through midday Sunday bringing very warm and mainly dry weather. A weak cold front will push southeast across the state Sunday night into Monday morning. Scattered showers and thunderstorms are possible ahead of the front. Another period of warmer than normal and mainly dry days will follow for Monday into at least early Wednesday. && .NEAR TERM /THROUGH SUNDAY/... Just some high clouds now. There was a few CU earlier. Been watching a cluster of showers and storms moving northward, but these look like they would stay west of central PA this evening. Another area over Lake Erie. The airmass over central PA not real moist, and with the sun setting, expect the evening to remain dry. Forecast temperatures look good still. Earlier discussion below. Strong ridge over the Mid Atlantic with 594 heights through Central PA will continue into Sunday. Skies should be mainly clear tonight. Dew points in the northern mountains still in the upper 50s to lower 60s so another comfortable night in the north. Temps and dew points will converge around the mid 60s by morning in the lower Susq Valley. Some low clouds or light fog may possibly form. && .SHORT TERM /SUNDAY NIGHT THROUGH 6 PM SUNDAY/... Will have to monitor the situation on Sunday. At this point, very warm air aloft during the day on Sunday may make it hard to fire up many showers or storms. Cooling aloft later Sunday night into Monday might lead to a better chance for showers and storms. Earlier discussion below. A weak cold front will bring the chance for showers or thunderstorms later Sunday afternoon/evening - mainly over northern and western sections of the state. Weighted our previous fcst POPs to the latest run of the Superblend. Little or no chc for precip across the far SE zones remains. SPC has placed the NW third of our CWA in a Marginal Risk for severe Sunday afternoon and evening...which looks pretty good based on moderate, westerly deep-layer shear and a SW-NE ribbon of rather impressive MU cape of 2500-3500 j/kg extending from near KELZ and KBFD...to KBTP. Gusty (and highly localized damaging) westerly winds will accompany the storms in the 18Z Sunday - 01Z Monday period in the MRGL Risk area. Above normal temps will continue on Sunday with similar maxes (or perhaps just a few deg f lower than Sat`s across the Susq Valley). Highs expected to range from the mid 80s (mtns) to near 90F in the Lower Susq Valley. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... The extended period looks like it will feature a transition from a persistent upper-level ridge over the eastern United States to a weak upper-level trough by mid to late week. As a result, above-normal temperatures through the Tuesday-Wednesday timeframe will transition to near or a little below normal by the end of the period. A weakening cold front will push slowly SE through the Commonwealth Sunday night into Monday morning accompanied by isolated to scattered showers/thunderstorms. The frontal boundary is expected to wash out near or just south of the Mason/Dixon line during the day Monday. Abundant low-level moisture, mesoscale convergence and some orographic lift/heating via the east to NE low level flow regime across the mountains of SW PA will focus the best chance for showers and scattered thunderstorms there Monday afternoon. Monday night through Wed morning looks to be dry with generally light wind and just the possibility of patchy early morning valley fog. Medium range guidance agrees with a second-stronger cold front pushing SE across the area Wednesday afternoon or early Thursday, with a renewed chance for showers and thunderstorms. This front will be followed by a cool-down for the end of next week. Max temps should be mainly in the 70s Thursday into the weekend over the northern and western higher terrain, with low to mid 80s elsewhere as an upper trough amplifies from central Quebec...to the Mid Atlantic Piedmont. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/...
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Mainly VFR conds and light wind expected through Sunday, as high pressure ridge remains in place across eastern Pa. Some patchy fog could reduce vsbys in a few spots early Sunday morning. At this point, significant reductions appear unlikely, but can`t completely rule out a brief period of IFR in the vicinity of KUNV, where sfc obs and near term models are pooling an area of enhanced low level moisture. The other potential threat to aviation will be sct tsra developing across northwest Pa during the afternoon in advance of an approaching cold front over the Great Lakes. The best chance of a brief tsra impact would be at KBFD, however potential could extend into the KJST/KUNV/KIPT corridor by early evening. Outlook... Mon...AM fog poss, mainly KBFD. Isold PM tsra impacts poss south. Tue...AM fog poss, mainly KBFD. Wed...Isold PM tsra impacts possible. Thu...No sig wx expected.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Watson/Lambert NEAR TERM...Watson/Martin SHORT TERM...Watson/Lambert/Martin LONG TERM...La Corte AVIATION...Fitzgerald

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