A shortwave traveling north over a broad ridge in the central U.S dragged a weak cold front over the Ohio Valley. This coldfront set off thunderstorms in the afternoon and evening hours on the 18th. There were several reports of wind damage in eastern Ohio and western Pennsylvania with more than 11,000 people without power in western PA alone. In addition urban flooding and flash flooding occurred in various parts of Allegheny and Beaver counties. Cars were stranded in high water right around rush-hour on Washington Blvd in downtown Pittsburgh.

Flash Flood in ALLEGHENY, PENNSYLVANIA
From 18-JUL-11 16:32:00 to 18-JUL-11 20:30:00 (EST-5)
Location: ASPINWALL
Flood cause: Heavy Rain
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Newspaper

Washington Blvd/Route 8 at the Negley Run intersection was closed due to rapidly rising water. Numerous cars were stranded or stalled with two people needing to be rescued from their vehicles.

Flood in ALLEGHENY, PENNSYLVANIA
From 18-JUL-11 17:00:00 to 18-JUL-11 17:30:00 (EST-5)
Location: JEFFERSON
Flood cause: Heavy Rain
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Newspaper

The Pittsburgh Tribune Review reports that a half dozen motorists were stuck when their vehicles stalled in high water on Route 51 between Coal Valley Rd in Jefferson Hills and the Southland Four Seasons shopping center in Pleasant Hills.

Flood in BEAVER, PENNSYLVANIA
From 18-JUL-11 17:00:00 to 18-JUL-11 18:00:00 (EST-5)
Location: SOUTH HGTS
Flood cause: Heavy Rain
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Newspaper

Beaver Times newspaper reports of flooding on Route 65 near Fourth Street, just north of Ambridge. Water was waist deep and stalled vehicles.

Thunderstorm Wind in VENANGO, PENNSYLVANIA
From 18-JUL-11 12:05:00 to 18-JUL-11 12:05:00 (EST-5)
Location: SPRINGVILLE
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported a large tree down on power lines.

Thunderstorm Wind in BUTLER, PENNSYLVANIA
From 18-JUL-11 14:20:00 to 18-JUL-11 14:20:00 (EST-5)
Location: RENFREW
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reports trees and a utility pole down.

Thunderstorm Wind in BUTLER, PENNSYLVANIA
From 18-JUL-11 14:30:00 to 18-JUL-11 14:30:00 (EST-5)
Location: RENFREW
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Broadcast Media

The media reports trees and power lines down in Renfrew.

Thunderstorm Wind in BEAVER, PENNSYLVANIA
From 18-JUL-11 16:40:00 to 18-JUL-11 16:40:00 (EST-5)
Location: SUNFLOWER
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency management reports trees down outside of Rochester.

Thunderstorm Wind in WASHINGTON, PENNSYLVANIA
From 18-JUL-11 18:35:00 to 18-JUL-11 18:35:00 (EST-5)
Location: GINGER HILL
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Department of Highways

Pennsylvania Department of Transportation reports a couple of trees down on Ginger Hill Road.

Thunderstorm Wind in ALLEGHENY, PENNSYLVANIA
From 18-JUL-11 17:45:00 to 18-JUL-11 17:45:00 (EST-5)
Location: WHITEHALL
Magnitude: 52.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Utility Company

Duquesne Light reported downed trees and wires in Baldwin, Findley, Leet, Liberty, Port Vue, and Moon.