Unseasonably warm air for mid-March greeted Pennsylvanian's on the morning of the 13th, and a stong cold front quickly advanced through the midwest during the afternoon hours.
Very strong winds only one to two thousand feet aloft lead to a day with lots of thunderstorms with gusty winds. A few of these bow-echo cells made damaging wind gusts of 60 mph or more.
The best cell of the day moved in a long path from western PA (near Butler) thorough Clearfield County, Northern Clinton County and over to Sullivan County. It made wind damage most of the way along it's path.
The Clearfield Lawrence County Airport reported a peak wind gust of 51 knots (59 mph). Trees were reported down in other parts of northern Clearfield County. More trees fell along Route 120 in Northern Clinton County, west of Renovo.
Sporadic, light, tree damage occurred from this same storm cell as it move through Northern Lycoming County, and then pushed two trees onto Route 42 near Muncy Valley (in Sullivan County).
Damage occurred from the same line of storms, but from other thunderstorm cells in Eastern Tioga County, near Covington, PA, where trees were blown down and a number of buildings damaged.
A wind gust of 60 mph was estimated in Northern Dauphin County (near Millersburg), as well.

Preliminary Damage Reports in Text format

Reflectivity from KCCX Around the time the 51 knot gust happened at KFIG (Clearfield Airport)

Reflectivity Cross Section (Vertical Slice) from KCCX as the storm blew down trees east of DuBois

Morning Atmospheric Soundings (balloon data) from Pittsburgh, PA and Wilmington, OH.