Thunderstorm Wind in Blair County, Pennsylvania

The RWIS station on Interstate 99 at Bellwood measured a 59 mph gust as a line of severe thunderstorms moved through.

A cold front west of central Pennsylvania slowly began to drift eastward during the morning hours and throughout the day on March 16, 2025 allowing ample lift in an environment with sufficient shear and instability to form a quasi-linear convective system across western Pennsylvania. This QLCS continued moving into a more favorable environment across central Pennsylvania, with increased instability from a dry slot coupled with a favorable entrance region of an upper-level jet maximum to produce enhanced shear. This allowed for the QLCS to strengthen across central Pennsylvania and caused extensive damage across west-central Pennsylvania with ample low-level shear spawning two tornadoes in Clinton and Elk counties. Farther east, a less favorable environment was in place with more stable air and lower shear; however, the forward momentum of the QLCS allowed for further damage across northeastern Pennsylvania. Later in the evening, thunderstorms began to form south of central Pennsylvania and gradually drifted northeastward with upper-level support. Strong-to-severe thunderstorms were present along the Mason-Dixon line with a severe thunderstorm producing quarter and ping pong-sized hail in York County.