Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 211728 AFDCTP Area Forecast Discussion National Weather Service State College PA 128 PM EDT Wed Mar 21 2018 .SYNOPSIS... 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. Odds for a dry weekend have increased over the last 48 hours as storm system passes to the south of PA. && .NEAR TERM /THROUGH TONIGHT/... Persistent moderate to heavy snow continues across south-central PA. The storm continues to evolve very slowly, allowing snow to pile up with storm totals around 1 foot in some locations as of 12pm. For additional snow/QPF, followed blend of High Res Models and Ensembles which support another 4-8"+ across most of the warning area. Heaviest snow (rates ~1 in/hr at times) should shift south/east with time into the lower Susquehanna Valley by early evening before tapering off from west to east into tonight. Final storm totals will range from 10 to 20 inches and will make this the heaviest snow event this winter season. A quick 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 storm. Webcams and social media reports indicate road conditions are variable (wet, slushy, snow covered) and changing given periods of heavy snow rates offset by melting caused by relatively warm pavement surfaces and time of day/year. Expect travel impacts and disruptions to continued through the evening commute. && .SHORT TERM /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, 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 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 /18Z WEDNESDAY THROUGH MONDAY/... For 12Z TAFS...made some adjustments. Took all night...but snow reaching the ground across much of the area now. Thus made lower values prevailing. Bands of snow will be across the area for most of the day. Activity will slowly taper off from west to east this evening. Outlook... Thu...No sig wx expected. Fri...Cig restrictions poss NW. Sat-Sun...No sig wx expected. && .CTP WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 8 PM EDT this evening for PAZ017>019-045-049>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 LONG TERM...Fitzgerald AVIATION...Martin is the U.S. government's official web portal to all federal, state and local government web resources and services.