Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 221217 AFDCTP Area Forecast Discussion National Weather Service State College PA 717 AM EST Wed Nov 22 2017 .SYNOPSIS...
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A cold front will push southeast across the region early this morning. High pressure will then build into the area for the second half of the week. Another cold front will push through Pennsylvania on Saturday.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/... Regional radar mosaic at 09Z showing a narrow band of light precip falling in the cold air behind cold front over northwest Pa. Despite meager PWATs, relatively strong fgen forcing in right entrance region of upper jet streak will support a period of rain turning to snow across the northwest mountains as this band moves through early this morning. Marginal surface temps and short duration of snow should limit accums to less than an inch across the northwest mountains. With shortwave and associated jet streak lifting north of Pa, expect band of rain/snow to diminish as it pushes southeast later this morning, with HREFV3 data supporting only a slight chance of measurable precip southeast of the Allegheny Plateau. However, incipient secondary low off the Mid Atlantic coast could potentially clip eastern Lancaster County with a period of rain around dawn. Will maintain the chance of rain/snow across the northeast portion of the forecast area through around 15Z in association with weakening post-frontal fgen forcing. HREFV3 also continues to support chance POPs for showers over eastern Lancaster Co through about 15Z in association with developing low off the Mid Atlantic coast. Elsewhere, seasonably cold air flowing over the relatively mild waters of the Grt Lks will produce scattered lake effect snow showers today across the Allegheny Plateau. However, approach of high pressure and falling inversion heights should result in minimal accums of at most a fresh dusting, mainly during the first half of the day. For most of central Pa, today will be dry and breezy with temps below normal. GEFS mean 8h temps between -4C and -9C should translate to highs from the low 30s across the high terrain of northwest Pa, to the upper 40s across Lancaster Co. Although the day will dawn mainly cloudy across central Pa, expect gradual brightening, mainly east of the mountains, as inversion heights fall this afternoon. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Any lingering snow showers/flurries across the northwest mountains should end tonight, as surface ridge axis builds into the area. Clearing skies and diminishing winds will allow temps to fall below seasonal norms, with readings mostly in the low to mid 20s by dawn. Surface ridge and associated low PWAT air mass over the area should ensure dry weather and light wind for Thanksgiving. However, passage of an upper level shortwave is likely to produce enough mid and high level cloudiness to term Thursday partly cloudy. Mixing down GEFS mean 925 temps of around -2C should translate to max temps from the mid 30s over the northwest mountains, to the low 40s in the Susq Valley. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... High confidence of fair and seasonable weather Thursday night into Friday, as all guidance continues to indicate ridging aloft in advance of next system. Expect a somewhat milder day Friday, as surface high passes off the coast and return southwest flow ensues. Relatively good agreement among med range guidance into next weekend, with a cold front passage likely early Saturday. Scattered rain showers will likely accompany the front Sat, followed by a period of lake effect snow showers Sat night into Sunday, as another blast of seasonably chilly air charges across the relatively mild waters of the Grt Lks. ECENS and GEFS both support below normal temperatures Sunday, as deep upper level trough swings over the northeast states. All signs are pointing toward fair and milder weather early next week, as upper ridging is progged along the eastern seaboard in all med range guidance. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
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A cold front will move east of the airspace by late morning. Associated forcing is producing some light rain and snow showers along the front. This is turn is producing ceiling and a few vsby reductions...mainly across the western mtn airfields; IFR at KJST and KBFD, MVFR at KAOO. VFR is expected elsewhere and current reductions should improve to VFR in the 16 to 18z time frame. Gusty northwest winds will also accompany the passage of the front and affect all airfields through at least the daylight hours. VFR expected overnight tonight and into Thanksgiving Day as high pressure builds into the region. Overall pattern favors no big weather systems into the upcoming weekend, but frontal passages with limited moisture every few days. Outlook... Thu-Fri...No sig wx expected. Sat...Chance of rain/snow showers. Sun...Chance of snow showers across the NW in the morning. Otherwise no sig wx expected.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Fitzgerald NEAR TERM...Fitzgerald SHORT TERM...Fitzgerald LONG TERM...Fitzgerald AVIATION...Gartner/Martin

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