Area Forecast Discussion
Issued by NWS State College, PA

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280 FXUS61 KCTP 011621 AFDCTP Area Forecast Discussion National Weather Service State College PA 1121 AM EST Thu Dec 1 2016 .SYNOPSIS...
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A large and deep storm system will move slowly through Quebec over the next couple of days keeping a prolonged period of cool northwest flow over the local area. High pressure will build in for a brief time Sunday before the next frontal system approached early next week.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Flow over the region is transitioning into a cooler west- northwest flow pattern today as upper low cener spins over eastern Ontario/western Quebec. Expect the usual cold season strato- cu clouds and scattered showers of rain or snow that will mainly favor the NW and Laurel Highlands. Cloud cover will scattere out quickly from central to southeast counties as drying downslope flowdevelops. The low level wind field will initially be mainly out of the west which normally confines the best lake enhanced showers over southern NY or extreme NW Pa. I leaned closer to HRRR POPs with the meso model confining most showers very close to the lake during the day. The wind is expected to become a bit more NWLY overnight which will help bring precipitation more into my NWRN zones. However the upstream air is only marginally cold and BUFKIT shows limited low level instability of the air passing over the lakes so I am not too excited about the prospects for any kind of significant lake effect.
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&& .SHORT TERM /FRIDAY/... The cold NW flow will remain air in place for Friday, but again the cold air is unimpressive so NW snow shower activity is not expected to amount to more than nuisance amounts. With high temps expected to be above freezing, most areas will ave a hard time making any snow stick at all. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Most areas will be precipitation free Sat-Mon except the northwestern areas where some the over-lake trajectory will bring the usual areas the familiar kind of lake effect showers that happen so often in the cool season. Sunday looks like we will see a brief respite as high pressure moves over the state. By late Sunday into the overnight, a period of light snow is possible as a northern stream shortwave races through the region with a burst of warm advection. QPF looks to be on the order of a tenth of an inch or less, but occurring overnight many places could see their first coating of snow of the young season. By midweek there is decent agreement in bringing the SW US upper low up through the OHIO Valley as a shearing out shortwave and diffuse surface low. Unless cold air damming traps enough chilly air in the low levels to make for some freezing rain, the precip type with this midwest system looks to be mainly rain. The end of the week brings some model disagreement with the GFS/GEFS being faster than the ECMWF with the next upper trof and frontal system. The end of the extended has just a chance of showers given the lack of confidence. && .AVIATION /16Z THURSDAY THROUGH MONDAY/...
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Surface ridging and arrival of drier air has brought improving conditions across Central Pa, with generally VFR across the eastern third of the state. Across the western and central sections, residual low level moisture ascending the Appalachian Mtns is resulting in MVFR stratocu . Through the afternoon, expect persistent MVFR CIGs over the upslope region from KBFD to KJST and possibly extending into KUNV/KAOO, and conds across the east. After a brief lull in the wind speeds this morning over Eastern Pa, expect a rather gusty daytime, as stronger flow aloft begins mixing to ground level. Bufkit soundings support frequent gusts to around 25kts across the entire region later today. A WSW wind flow should keep lake effect snow showers mainly north of the border today. However, latest model data suggests a slight shift in the wind could cause the lake effect snow showers to move from upstate NY into NW Pa tonight. Thus, IFR vis reductions appear possible at KBFD tonight. Outlook... Fri-Sat...MVFR CIGS and ocnl SHSN/IFR vis possible KBFD/KJST. Sun...Slight chance of light snow/reduced vis at night. Mon...No sig wx expected.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte/Gartner NEAR TERM...La Corte/Gartner SHORT TERM...La Corte LONG TERM...La Corte AVIATION...Fitzgerald/Gartner

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