Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 241835 AFDCTP Area Forecast Discussion National Weather Service State College PA 235 PM EDT WED AUG 24 2016 .SYNOPSIS...
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A seasonably warm and humid late-summer weather pattern will continue across Central Pennsylvania through the weekend. The best chance for scattered showers or thunderstorms will come on Thursday and early next week.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Deep layer moisture continues to increase over central PA early this afternoon as return southwest flow has commenced west of the 850 mb ridge moving offshore south of Long Island. Sct fair weather cumulus has slightly more vertical extent than Tuesday as a result...but mid to upper trop is stable and not expecting any diurnal activity this afternoon or evening. Tonight will be fair as deep layer moisture continues to increase. Late night convective complex over the Ohio Valley will be weakening as it makes a dive towards southwest PA in the pre dawn hours...which could bring the West Central Mountains and Laurel Highlands some showers early Thursday morning before complete dissipation. Earlier ARW-E depicted more of a classically right turning complex dissipating as it reached the MD panhandle Thu morning...while latest HRRR is indicating a line of showers and thunderstorms extending from southwest trip of Lake Ontario to southeast Ohio by 07z tonight. Think the latter is more likely to occur...as good moisture convergence along the elongated 850 mb jet advancing from the eastern GLAKS should maintain convection through late tonight before slowly weakening in the pre dawn hours Thu morning. Will adjust pops accordingly for late tonight into Thursday morning.
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&& .SHORT TERM /THURSDAY/...
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Decaying frontal boundary will feed on 2"+ PW Thursday leading to scattered coverage of showers and thunderstorms on Thursday. Main problem may be developing sufficient CAPE as overnight convective remnants from the Ohio Valley may plague a good portion of central PA into Thu afternoon. Latest SPC Day 2 has western portion of my CWA in MRGL risk for Thu aftenoon...as setup is far from ideal. Still...the moist and unstable air mass will support scattered convection ahead of the weakening front. Sfc dewpoints will make a run at or exceed 70 in many areas...so it will be noticeably stickier than Wed afternoon. Highs central and north should be a few degrees lower due to cloud cover...while southern areas will warm another degree or two over Wed highs.
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&& .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
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The front/sfc trough becomes very diffuse on Friday as it slips south toward the Mason Dixon line. Weak instability and rich boundary layer moisture in advance of the weak front/sfc trough supports maintaining very low tstm probs /20 pct or less/ primarily across the southern 1/2 to 1/3 of the CWA. However, this may be overdone given increasing large scale subsidence and falling PWATs. Temperatures and humidity will be on the rise with 90F heat likely returning to the Lower Susquehanna Valley by Friday. The deep-layer ridge will gradually slide off the Mid Atlantic coast this period, which allows another frontal boundary to sink southward from the Lower Lakes and become quasi-stationary over PA early next week. This will favor unsettled conditions Mon-Tue with POPs trending upward following a mainly dry weekend. Temps will remain above normal by late August standards.
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&& .AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
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VFR conditions will prevail through this evening. Isolated MVFR conds in shra from dying convective complex overnight may impact far western terminals Thursday morning. Sct mainly afternoon shra and tsra central and western areas on Thursday. Outlook... Wed...Patchy AM fog possible, otherwise VFR. Thu...Generally VFR, but with Isold pm tsra impacts possible, mainly w and c mtns. Fri...Morning low cigs possible across the Western Mountains, otherwise VFR. Sat-Sun...No sig wx expected. Mon...Generally VFR...but with Isold pm tsra impacts possible.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...DeVoir NEAR TERM...DeVoir SHORT TERM...DeVoir LONG TERM...Steinbugl AVIATION...DeVoir/Gartner

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