Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 100300 AFDCTP Area Forecast Discussion National Weather Service State College PA 1000 PM EST Sat Dec 9 2017 .SYNOPSIS... Low pressure will move off the mid Atlantic coast tonight. A deep upper level trough will remain over the eastern conus into Thursday, before a westerly flow of milder air works into the area by next weekend. Low pressure moving just north of the area late Sunday will bring some snow to the north and west Sunday into Sunday night. Another low moving just north of the area late Monday night will bring some snow to the area late Monday into Tuesday, mainly across the north and west. && .NEAR TERM /UNTIL 7 AM SUNDAY MORNING/... In a little break right now. Finally rid of the snow in the SE. Clear slot over the central counties moving west. The higher clouds in the west continue to move east and thicken somewhat. A strong short wave will move overhead shortly, leading to NVA. As the trough axis moves eastward, snow showers will pop in the cold air to the west of the trough. Accumulations will be very light, less than an inch almost everywhere by sunrise. The winds are also favorable for a brief period of lake effect late tonight and the first part of Sunday. So, Warren county could get more than an inch by sunrise. But, bands look to be rather transitory. Clearing may be tough to find, but the SE may become clear shortly and hold on all night. Winds will pick up in the SW and get gusts over 20kts. && .SHORT TERM /7 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... Aside from aforementioned lake effect snow into Sunday afternoon, downsloping subsidence should result in partly sunny, dry weather east of the mountains Sunday. Mixing down model 850mb temps of -10C to -12C translate to below normal max temps Sunday, ranging from the upper 20s over the Alleghenies, to the mid 30s in the Susq Valley. The gusty west wind will add an additional bite to the air. Ensemble qpf supports accums generally less than an inch across the Allegheny Plateau by late Sunday. However, the favored snowbelt of northwest Warren could be around 3 inches. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... A weak low moving north of the area will bring a northwest flow of air to the area late Sunday into early Monday. This will result in some snow showers. A stronger low moving across upstate New York on Tuesday will bring some snow to the area late Monday night into Tue. THis will be followed by a cold northwest flow across the Great Lakes. This will result into some snow showers off the lakes. The west coast ridge weakens some toward next weekend, which will result in a westerly flow of milder air working into the area. Minor changes to the package. Went with dry conditions next weekend. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... The snow bands have moved eastward however, Periods of IFR will continue at LNS with reduced vsbys until around 06Z. The focus will continue to shift to the NW as the westerly upslope flow will continue to bring restrictions and widespread snow showers to the northern/western mountains along with brisk NW flow and the potential for scattered heavier squalls that will linger into the first half of Sunday. Scattered snow showers will bring intermittent MVFR incursions into the central mountains, while downslope flow will keep the SE VFR. Outlook... Sun...AM snow showers/reductions likely Allegheny Plateau, becoming confined to the NW mtns in the afternoon. Scattered squalls also poss. Mon...Cig reductions likely western portions. PM light snow developing, mainly northwest Pa. Mon night and Tuesday...Periods of light snow. Widespread MVFR likely, with periods of IFR and brief LIFR cigs and vsbys. Wed...Reductions poss west in sct snow showers. Otherwise VFR. Thu...Still a chance of a few snow showers. && .CTP WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 1 AM to 3 PM EST Sunday for PAZ004. && $$ SYNOPSIS...Dangelo NEAR TERM...Dangelo SHORT TERM...DeVoir/Fitzgerald LONG TERM...Martin AVIATION...DeVoir/Ceru

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