Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 101212 AFDCTP Area Forecast Discussion National Weather Service State College PA 712 AM EST Sun Dec 10 2017 .SYNOPSIS... A deep upper level trough will remain over the eastern conus through the upcoming week with clippers likely affecting the area Monday night and also late Thursday. The upper trough will likely lift out by next weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Light, orographically enhanced lake effect snow should taper off over the Alleghenies by this afternoon, as boundary layer flow backs to the southwest. HREFV2 qpf is supporting an additional inch or so between 12Z-18Z across the snowbelt of northwest Warren County, while no more than an additional dusting is expected over the rest of the Allegheny Plateau. Downsloping subsidence should result in partly sunny, dry weather east of the mountains later today, while stratocu trapped beneath subsidence inversion lingers over the western portion of the forecast area. Mixing down model 850mb temps of -10C to -12C translates to below normal max temps today, ranging from the upper 20s over the Alleghenies, to the mid and upper 30s in the Susq Valley. A gusty west wind will add an additional bite to the air. Bufkit soundings support frequent gusts to around 20kts. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... 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. 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 /12Z SUNDAY THROUGH THURSDAY/...
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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.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 3 PM EST this afternoon for PAZ004. && $$ SYNOPSIS...Fitzgerald NEAR TERM...Fitzgerald SHORT TERM...Fitzgerald LONG TERM...Fitzgerald AVIATION...RXR

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