An approaching cold front helped trigger strong to locally severe thunderstorms during the late afternoon and early evening of the 1st mainly in southeastern Pennsylvania.

Thunderstorm Wind in MONTGOMERY, PENNSYLVANIA
From 01-AUG-11 15:51:00 to 01-AUG-11 15:51:00 (EST-5)
Location: KING OF PRUSSIA
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A severe thunderstorm knocked down a few trees in King of Prussia (Upper Merion Township).

Thunderstorm Wind in BERKS, PENNSYLVANIA
From 01-AUG-11 15:25:00 to 01-AUG-11 15:25:00 (EST-5)
Location: OLEY
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A severe thunderstorm knocked down a couple of trees in Oley.

Thunderstorm Wind in BERKS, PENNSYLVANIA
From 01-AUG-11 15:34:00 to 01-AUG-11 15:34:00 (EST-5)
Location: REHRERSBURG
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

A severe thunderstorm knocked down a couple of trees in Tulpehocken Township..

Thunderstorm Wind in CARBON, PENNSYLVANIA
From 01-AUG-11 16:00:00 to 01-AUG-11 16:00:00 (EST-5)
Location: LEHIGHTON CARBON ARP
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A severe thunderstorm knocked down a few trees in Mahoning Township..

Thunderstorm Wind in DELAWARE, PENNSYLVANIA
From 01-AUG-11 16:53:00 to 01-AUG-11 16:53:00 (EST-5)
Location: SHARON HILL
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A severe thunderstorm knocked down large tree limbs in Sharon Hill.

Thunderstorm Wind in PHILADELPHIA, PENNSYLVANIA
From 01-AUG-11 16:22:00 to 01-AUG-11 16:34:00 (EST-5)
Location: MANAYUNK
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

A severe thunderstorm knocked down about two dozen trees in Philadelphia, in the Manayunk, West and Lower Northeast section of city.

Thunderstorm Wind in PHILADELPHIA, PENNSYLVANIA
From 01-AUG-11 16:56:00 to 01-AUG-11 16:56:00 (EST-5)
Location: (PHL)PHILADELPHIA IN
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A severe thunderstorm produced a wind gust of 60 mph at the Philadelphia International Airport.

Hail in DELAWARE, PENNSYLVANIA
From 01-AUG-11 16:49:00 to 01-AUG-11 16:49:00 (EST-5)
Location: DREXEL HILL
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Penny size hail fell in Drexel Hill (Upper Darby Township).

Hail in DELAWARE, PENNSYLVANIA
From 01-AUG-11 17:24:00 to 01-AUG-11 17:24:00 (EST-5)
Location: BOOTHWYN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A severe thunderstorm dropped quarter size hail in Boothwyn (Upper Chichester Township).

Hail in DELAWARE, PENNSYLVANIA
From 01-AUG-11 16:53:00 to 01-AUG-11 16:53:00 (EST-5)
Location: SHARON HILL
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A severe thunderstorm dropped nickel to quarter size hail in Sharon Hill Borough.

Hail in PHILADELPHIA, PENNSYLVANIA
From 01-AUG-11 16:56:00 to 01-AUG-11 16:56:00 (EST-5)
Location: (PHL)PHILADELPHIA IN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A severe thunderstorm also dropped quarter size hail at the Philadelphia International Airport.