Thunderstorm Wind in Armstrong County, Pennsylvania

Trees were blown down in Rural Valley.

A strongly forced band of convection developed over West Virginia in the morning ahead of an approaching front, and quickly lifted north-northeastward into Pennsylvania through the early afternoon. Despite relatively modest instability, very strong deep layer shear, along with largely unidirectional southerly flow and elongated hodographs, supported the continuation of significant severe storms. Large impact was felt from straight-line wind, with gusts in the 60 to 80 MPH range, locally higher, causing widespread damage to trees, power lines, and structures. The line of storms continued into Pennsylvania, where the environment was more favorable for tornadic development. In addition to damaging winds, a number of large hail reports were received, with some stones as large as 1.75 inch diameter. Also, embedded supercells/mesovortices produced five confirmed tornadoes during the afternoon (one of which crossed from Fayette County into Westmoreland County).