Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 101610 AFDCTP Area Forecast Discussion National Weather Service State College PA 1110 AM EST Sun Dec 10 2017 .SYNOPSIS... A clipper system will bring snow and difficult travel to parts of central Pennsylvania early this week. A shot of arctic air will enhance lake effect snow and may produce dangerous snow squalls on Tuesday. Gusty winds along with the brutally cold air will result in wind chills below zero over the Alleghenies by Wednesday. && .NEAR TERM /THROUGH TONIGHT/... Radar trends show lake-effect snow shifting orientation into southwest NY as boundary layer flow backs to the WSW ahead of next shortwave dropping into the Great Lakes. Light snow showers and flurries over the Alleghenies should taper off by this afternoon. Plan to allow the winter wx advisory expire at 3 PM as main LES shifts north of PA/NY border. Visible sat trends indicate some breaks in the stratocu clouds over southeast PA, revealing the snow that fell yesterday to the along and east of the I-81 corridor. Cut a few degrees off maxT over these snowcovered areas but gusty winds will make it feel like its in the teens to low 20s. Winds should gradually subside into tonight. A weak, moisture-starved clipper will dive south across the region tonight, accompanied by no more than scattered flurries for much of the forecast area. However, orographic enhancement could result in a light accum of less than an inch over the northwest mountains or Laurel Highlands. && .SHORT TERM /MONDAY/... Surface ridge will briefing track across the region Monday, supplying fair weather for most of the forecast area. Next in series of clippers will approach late in the day, perhaps spreading some light snow into the northwest counties before dark. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... All model guidance tracks clipper north of Pa Monday night, which should keep the most substantial snow north of Pa. However, blend of latest guidance still supports a likely period of light snow across central Pa, with accums generally in the 1-3 inch range. The coldest air of the season is forecast to arrive behind this system with a shot of arctic air and more lake effect snow lasting through midweek. WPC graphics indicating about a 30 pct chance of exceeding winter storm criteria across the snowbelt of Warren County Tue into Wed AM, so will highlight this potential in the HWO for now. Tight pressure gradient will result in gusty winds to accompany the arrival of the cold air. A quick look at model data suggests wind advisory criteria is possible early Wed, as large scale subsidence and pressure fall/rise couplet moves through. Med range guidance indicates another clipper is likely to affect the area late Thursday with another potential light snowfall. After that, ECENS and GEFS both indicate upper trough will lift out, resulting in a marked warm up next weekend. Latest EC ensemble MOS guidance indicating temps returning to near or slightly above climo by next weekend. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... A deep upper level trough will remain over the region through the upcoming week with clippers likely affecting the area Monday night and also late Thursday. Sharp upper trough lifting across the area bringing reductions to northern/western mountains in light snow showers with MVFR conditions occasionally dropping to IFR there. As the day progresses, the snow showers will end and cigs will settle into MVFR over the NW mountains and likely jump to VFR in the Laurel Highlands. Central mountains seeing flurries with an MVFR deck hanging around for a couple more hours this morning before improving to VFR. And eastern areas will continue with VFR conditions. Winds will increase to 10-15 mph today with gusts into the low 20s across the western half. A weak shortwave tonight will bring renewed cig reductions across the west along with mainly flurries. Outlook... 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 until 3 PM EST this afternoon for PAZ004. && $$ SYNOPSIS...Steinbugl NEAR TERM...Fitzgerald/Steinbugl SHORT TERM...Fitzgerald LONG TERM...Fitzgerald AVIATION...RXR is the U.S. government's official web portal to all federal, state and local government web resources and services.