An upper air disturbance coupled with a surface trough helped trigger strong to locally severe thunderstorms during the evening in southeastern Pennsylvania. Scattered thunderstorms persisted through the night.

Hail in BUCKS, PENNSYLVANIA
From 18-AUG-11 17:40:00 to 18-AUG-11 17:40:00 (EST-5)
Location: NEWTOWN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A severe thunderstorm dropped quarter size hail in Newtown Township.

Hail in CHESTER, PENNSYLVANIA
From 18-AUG-11 17:58:00 to 18-AUG-11 17:58:00 (EST-5)
Location: LANDENBERG
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A severe thunderstorm dropped half dollar size hail in Ladenberg (New Garden Township).

Hail in CHESTER, PENNSYLVANIA
From 18-AUG-11 18:30:00 to 18-AUG-11 18:30:00 (EST-5)
Location: WEST CHESTER
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A thunderstorm dropped nickel size hail in West Chester.

Hail in DELAWARE, PENNSYLVANIA
From 18-AUG-11 18:45:00 to 18-AUG-11 18:45:00 (EST-5)
Location: BOOTHWYN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

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

Hail in MONTGOMERY, PENNSYLVANIA
From 18-AUG-11 19:30:00 to 18-AUG-11 19:30:00 (EST-5)
Location: FT WASHINGTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A severe thunderstorm dropped quarter size hail in Fort Washington (Upper Dublin Township).

Hail in CHESTER, PENNSYLVANIA
From 18-AUG-11 17:55:00 to 18-AUG-11 17:55:00 (EST-5)
Location: STRICKERSVILLE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped nickel size hail in London Britain Township.

Hail in MONTGOMERY, PENNSYLVANIA
From 18-AUG-11 19:35:00 to 18-AUG-11 19:35:00 (EST-5)
Location: HORSHAM
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped nickel size hail in Horsham Township.

Hail in BUCKS, PENNSYLVANIA
From 18-AUG-11 19:40:00 to 18-AUG-11 19:40:00 (EST-5)
Location: FURLONG
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped penny size hail in Furlong (Buckingham Township).

Thunderstorm Wind in CHESTER, PENNSYLVANIA
From 18-AUG-11 17:55:00 to 18-AUG-11 17:55:00 (EST-5)
Location: STRICKERSVILLE
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 London Britain Township.

Thunderstorm Wind in PHILADELPHIA, PENNSYLVANIA
From 18-AUG-11 19:02:00 to 18-AUG-11 19:02:00 (EST-5)
Location: (PHL)PHILADELPHIA IN
Magnitude: 54.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A severe thunderstorm produced a wind gust to 62 mph at the Philadelphia International Airport.

Thunderstorm Wind in MONTGOMERY, PENNSYLVANIA
From 18-AUG-11 19:01:00 to 18-AUG-11 19:01:00 (EST-5)
Location: NARBERTH
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A severe thunderstorm knocked down trees in Lower Merion Township.

Thunderstorm Wind in MONTGOMERY, PENNSYLVANIA
From 18-AUG-11 19:30:00 to 18-AUG-11 19:30:00 (EST-5)
Location: PENLLYN
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A severe thunderstorm knocked down trees in Lower Gwynedd Township.

Thunderstorm Wind in MONTGOMERY, PENNSYLVANIA
From 18-AUG-11 19:30:00 to 18-AUG-11 19:30:00 (EST-5)
Location: NORTH WALES
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A severe thunderstorm knocked down trees in Upper Gwynedd Township.

Thunderstorm Wind in MONTGOMERY, PENNSYLVANIA
From 18-AUG-11 19:30:00 to 18-AUG-11 19:30:00 (EST-5)
Location: ABINGTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A severe thunderstorm knocked down trees in Abington Township.

Lightning in DELAWARE, PENNSYLVANIA
From 19-AUG-11 01:10:00 to 19-AUG-11 01:10:00 (EST-5)
Location: GLENOLDEN
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Newspaper

A lightning strike and ensuing fire damaged a home on Leon Avenue in Norwood Borough. Lightning struck the roof and the fire started in the attic. Five fire companies battled the blaze and the fire was confined to the second floor of the house, but water damage extended into the first floor.  No injuries were reported.

Lightning in DELAWARE, PENNSYLVANIA
From 19-AUG-11 01:35:00 to 19-AUG-11 01:35:00 (EST-5)
Location: GLENOLDEN
Property damage: 250.00K
Crop damage: 0.00K
Reported by: Newspaper

A lightning strike and ensuing fire gutted a house on Norwinden Drive in Springfield Township. Firefighters arrived and found the house fire fully involved. It took about thirty minutes to extinguish the blaze.  No injuries were reported.