Area Forecast Discussion
Issued by NWS State College, PA

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373 FXUS61 KCTP 212004 AFDCTP Area Forecast Discussion National Weather Service State College PA 404 PM EDT Wed Mar 21 2018 .SYNOPSIS...
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Long-duration, early spring snowstorm will continue to impact south central Pennsylvania through Wednesday evening. The rest of the week will feature cooler than average temperatures and occasional flurries. The weekend now looks to be dry as the next weather system passes to the south of PA.
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Areas of moderate to locally heavy snow will continue across south- central PA through late evening. This early spring snow storm has evolved very slowly, allowing heavy, wet snow to pile up/weight on trees, increasing the risk for sporadic power outages. Heaviest snow will shift south/east with time into the lower Susquehanna Valley this evening before tapering off from west to east early tonight. Final storm totals will range from 10 to 20 inches and will make this the heaviest snow event for the 2017-18 winter season. A check of snowfall records at Harrisburg indicates a 2-day snowfall over 1 foot would crack the top-10 2-day March snowfalls, with the benchmark of course being the 1993 "superstorm." Webcams and social media reports indicate road conditions are variable (wet, slushy, snow covered) with heavier rates offset by relatively warm pavement surfaces and time of day/year. Expect travel impacts and disruptions to continue through the evening commute. In addition, watch out for slick spots on untreated roads, sidewalks and elevated surfaces as areas of slush and standing water from melted snow will freeze (minimum temps in the 20s).
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... Models showing a trailing shortwave diving southeast across the region on Thursday. Upper level diffluence ahead of this feature should result in a fair amount of cirrus. Low PWATS and temps aloft not cold enough to generate moisture flux from the Grt Lks, so not anticipating anything more than scattered flurries across the Laurel Highlands. NBM/Superblend indicating max temps Thursday ranging from the low 30s over the highest terrain of the Alleghenies, to the low 40s in the Susq Valley. However, a tight pressure gradient west of coastal low will produce gusty winds, making it feel even chillier. Bukfit soundings support frequent gusts between 20-25kts. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... All models tracking closed upper level low southeast across Pa on Friday, likely supporting scattered, diurnally-driven snow showers and flurries, mainly over the northern and western mountains. After that, focus will shift toward low pressure lifting out of the Miss Valley next weekend. NAEFS/ECENS indicate this system will likely pass too far south to affect central Pa, but will maintain the slight chance for a period of snow. After that, all med range guidance is showing upper level ridging building into the region, supporting a high confidence forecast of fair weather and warming temperatures early next week. A dying cold front could approach the area late Tuesday, potentially spreading showers into the state. Temperatures should remain below seasonal normals through most of the long term forecast, as upper trough remains over the northeast conus. However, moderation is anticipated by Tue/Wed, as upper trough lifts out. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... Widespread restrictions in snow from winter storm will persist across the southern half and especially southeast into the early evening. But trend will be for improving conditions to drop down from the north and work in from the west as storm pulls away. By late evening, VFR conditions should take hold in most locations, though increasing northerly flow should keep ceiling restrictions in the higher elevations of the west and possibly parts of the southern mountains. Outlook... Thu...No sig wx expected. Fri...Cig restrictions poss NW. Sat-Mon...No sig wx expected. && .CTP WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 8 PM EDT this evening for PAZ017>019-049>053. Winter Storm Warning until 8 PM EDT this evening for PAZ024>028-033>036-056>059-063>066. && $$ SYNOPSIS...Steinbugl NEAR TERM...Steinbugl SHORT TERM...Fitzgerald/RXR LONG TERM...RXR AVIATION...RXR is the U.S. government's official web portal to all federal, state and local government web resources and services.