A low pressure system moved east from the Ohio Valley and triggered severe thunderstorms over southwest and south-central Pennsylvania. An unseasonably warm, unstable air mass resided across much of southwest Pennsylvania while cooler, more stable air was entrenched just east of the Allegheny Mountains. The instability combined with strong low and mid level wind shear produced an early-season convective environment that was favorable for damaging winds, large hail and isolated tornadoes over southwestern portions of the state. An EF2 tornado was confirmed outside of the State College CWA in Hempfield Township near Greensburg, PA in Westmoreland County. The storm that produced the tornado dropped golf-ball sized hail across northern Somerset County. The cooler air mass and weaker low level instability farther to the east limited the threat for damaging winds and isolated tornadoes across south-central Pennsylvania, but enough elevated instability was still present and supportive of large hail.

Hail in SOMERSET, PENNSYLVANIA
From 23-MAR-11 15:31:00 to 23-MAR-11 15:31:00 (EST-5)
Location: SOMERSET
Magnitude: 0.80 
Crop damage: 0.00K
Reported by: Public

Hail in SOMERSET, PENNSYLVANIA
From 23-MAR-11 15:31:00 to 23-MAR-11 15:31:00 (EST-5)
Location: SOMERSET
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in SOMERSET, PENNSYLVANIA
From 23-MAR-11 15:31:00 to 23-MAR-11 15:31:00 (EST-5)
Location: SOMERSET
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in SOMERSET, PENNSYLVANIA
From 23-MAR-11 16:45:00 to 23-MAR-11 16:45:00 (EST-5)
Location: OGLETOWN
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in SOMERSET, PENNSYLVANIA
From 23-MAR-11 16:25:00 to 23-MAR-11 16:25:00 (EST-5)
Location: DAVIDSVILLE
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in BEDFORD, PENNSYLVANIA
From 23-MAR-11 16:55:00 to 23-MAR-11 16:55:00 (EST-5)
Location: ALUM BANK
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Emergency Manager

Quarter size (1 inch) hail reported in Pleasantville along SR 56.

Thunderstorm Wind in SOMERSET, PENNSYLVANIA
From 23-MAR-11 17:00:00 to 23-MAR-11 17:00:00 (EST-5)
Location: LAVANSVILLE
Magnitude: 50.00 EG
Property damage: 2.50K
Crop damage: 0.00K
Reported by: State Official

Thunderstorm winds estimated near 60 mph knocked down trees along SR 31.

Thunderstorm Wind in SOMERSET, PENNSYLVANIA
From 23-MAR-11 17:10:00 to 23-MAR-11 17:10:00 (EST-5)
Location: MEYERSDALE
Magnitude: 52.00 EG
Crop damage: 0.00K
Reported by: COOP Observer

The COOP observer in Meyersdale estimated thunderstorm wind gusts near 60 mph.

Hail in SOMERSET, PENNSYLVANIA
From 23-MAR-11 16:25:00 to 23-MAR-11 16:25:00 (EST-5)
Location: JEROME
Magnitude: 2.00 
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorm Wind in SOMERSET, PENNSYLVANIA
From 23-MAR-11 17:00:00 to 23-MAR-11 17:00:00 (EST-5)
Location: GEIGER
Magnitude: 50.00 EG
Property damage: 7.50K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm winds estimated near 60 mph knocked down several large trees along SR 281 in Geiger. The damaging winds also brought down utility wires and produced minor roof damage to a manure plant and several single family homes in Somerset Borough.