Area Forecast Discussion
Issued by NWS State College, PA

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551 FXUS61 KCTP 210133 AFDCTP Area Forecast Discussion National Weather Service State College PA 933 PM EDT Tue Mar 20 2018 .SYNOPSIS... An early spring, long duration winter storm will bring heavy snow to parts of south-central Pennsylvania through Wednesday. Dry weather with cooler than average temperatures is expected Thursday and Friday. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Intermittent light snow will continue across the southern half of CWA ovenight and latest sfc wave moves away. Still expect a very sharp gradient near I-80 with hires models showing little (<1") to no accumulation north of I-80. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... The 12z HREF shows the period of lighter snow overnight very well before ramping snow intensity up again Wednesday morning into the afternoon, with accum rates ~1 in/hr shifting from south central to southeast PA into the afternoon. Minor adjustments (slight increase) were made to snowfall on Day 2. Snow will taper off Wednesday evening in the lower Susquehanna Valley before ending Wednesday night. By the time the early spring/late March storm is over, some locations along and south of Rt22/I-81 will see around 1 foot of snow. && .LONG TERM /THURSDAY THROUGH TUESDAY/... By Thursday...the storm will continue to slowly lift away from our area. An upper level low will drop southeast late Thursday into Friday. This will likely bring more clouds back into the area...with a chance of some snow showers, and keep temperatures on the cooler side. A complex pattern for the upcoming weekend into early next week will prevail. Central PA will likely be between a developing storm off the coast...and on the edge of warm advection from the central plains. Thus much of the time it should be dry, but remain cool in low level northeasterly flow. By Sunday night into Monday, another upper wave slides through with ridging and cool surface high building in behind. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Snow definitely has tapered off quite a bit between 21z and 00z, as we wait for the second round of snow to spin up with the coastal low development. A good deal of VFR conditions being reported across the region, with areas of MVFR where the snow is falling. Suspect there are still areas of IFR, just not at reporting airfields. Snow will redevelop overnight, with another period of moderate to heavy snow Wednesday, especially southeastern areas. IFR to potentially LIFR conditions late tonight and Wednesday in southeastern airspace. TAFs farther west are tricky, as a sharp gradient to the snow expected. At this point, TAFs reflect a continuity from previous thinking, with widespread low restrictions in all but KBFD. Outlook... Wed...Snow and restrictions continue southern half. Some improvement later on Wed. Thu...No sig wx expected. Fri...Cig restrictions poss NW. Sat-Sun...No sig wx expected. && .CLIMATE... The Spring (Vernal) Equinox was at 12:15 PM today, March 20. Sunrise in State College, PA was at 7:14 AM and sunset at 7:23 PM, for a total day length of just over 12 hours. && .CTP WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 8 PM EDT Wednesday for PAZ017>019-045-049>053. Winter Storm Warning until 8 PM EDT Wednesday for PAZ024>028- 033>036-056>059-063>066. && $$ SYNOPSIS...Gartner NEAR TERM...Gartner SHORT TERM...Gartner/Steinbugl LONG TERM...RXR AVIATION...Jung CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.