On July 16th, a weak positively-tilted trough tracked from the Mississippi River Valley towards the Great Lakes today, while a surface front slowly sagged south from Lake Erie. Diurnal heating in an air mass with rich moisture plus increasing jet support yielded numerous thunderstorms, mainly favoring eastern Ohio and northwest Pennsylvania. Differential heating on the southern fringe of a thicker cloud deck and residual convective outflows provided the catalyst for development. Many reports of tree and power line damage were received. Also, multiple rounds of downpours during the day created flash flooding conditions in portions of Mercer and Venango Counties.

Thunderstorm Wind in BEAVER, PENNSYLVANIA
From 16-JUL-21 13:27:00 to 16-JUL-21 13:27:00 (EST-5)
Location: BRIDGEWATER
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Social Media

A large tree limb was brought down on to power lines.

Thunderstorm Wind in BEAVER, PENNSYLVANIA
From 16-JUL-21 13:40:00 to 16-JUL-21 13:40:00 (EST-5)
Location: BRIDGEWATER
Magnitude: 50.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: State Official

In the Beaver area, there were numerous reports of downed trees and power lines.

Thunderstorm Wind in BUTLER, PENNSYLVANIA
From 16-JUL-21 13:56:00 to 16-JUL-21 13:56:00 (EST-5)
Location: BUHLS
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Trees and wires were blown down along Route 68.

Thunderstorm Wind in BUTLER, PENNSYLVANIA
From 16-JUL-21 14:00:00 to 16-JUL-21 14:00:00 (EST-5)
Location: HOMEACRE
Magnitude: 50.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: State Official

Numerous trees and power lines were downed north of Butler.

Thunderstorm Wind in BUTLER, PENNSYLVANIA
From 16-JUL-21 14:14:00 to 16-JUL-21 14:14:00 (EST-5)
Location: BUTLER
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Trees and power lines were blown down on North Jackson Street.

Thunderstorm Wind in ARMSTRONG, PENNSYLVANIA
From 16-JUL-21 14:40:00 to 16-JUL-21 14:40:00 (EST-5)
Location: ADRIAN
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A tree was blown on to a house on Mosgrove Road.

Thunderstorm Wind in ARMSTRONG, PENNSYLVANIA
From 16-JUL-21 14:45:00 to 16-JUL-21 14:45:00 (EST-5)
Location: BELKNAP
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Trees were downed near County Route 1025.

Thunderstorm Wind in INDIANA, PENNSYLVANIA
From 16-JUL-21 15:07:00 to 16-JUL-21 15:07:00 (EST-5)
Location: PLUMVILLE
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: County Official

Along Route 4013, trees were blown down.

Thunderstorm Wind in WESTMORELAND, PENNSYLVANIA
From 16-JUL-21 15:14:00 to 16-JUL-21 15:14:00 (EST-5)
Location: BLACKBURN
Magnitude: 50.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: State Official

A tree was blown down on 7th Street Extension.

Thunderstorm Wind in INDIANA, PENNSYLVANIA
From 16-JUL-21 15:32:00 to 16-JUL-21 15:32:00 (EST-5)
Location: ARCADIA
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Power lines were downed on Cush Creek Road.

Thunderstorm Wind in INDIANA, PENNSYLVANIA
From 16-JUL-21 15:35:00 to 16-JUL-21 15:35:00 (EST-5)
Location: HILLSDALE
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Trees were blown down near Route 1026.

Thunderstorm Wind in WASHINGTON, PENNSYLVANIA
From 16-JUL-21 15:40:00 to 16-JUL-21 15:40:00 (EST-5)
Location: FINLEYVILLE
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Social Media

A tree was blown down on to an electrical pole adjacent to a house.

Flash Flood in MERCER, PENNSYLVANIA
From 16-JUL-21 18:46:00 to 16-JUL-21 21:30:00 (EST-5)
Location: NEW HAMBURG
Flood cause: Heavy Rain
Property damage: 50.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Crestview Drive near Reynold VFW was flooded.  Also, 20 feet of roadway washed out along SR-4014 near Reynolds Industrial Park Road.

Flash Flood in MERCER, PENNSYLVANIA
From 16-JUL-21 18:51:00 to 16-JUL-21 21:30:00 (EST-5)
Location: NEW HAMBURG
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: State Official

A vehicle was submerged in flood water on East Crestview Drive.

Thunderstorm Wind in ARMSTRONG, PENNSYLVANIA
From 16-JUL-21 19:05:00 to 16-JUL-21 19:05:00 (EST-5)
Location: ALADDIN
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Newspaper

One person injured due to tree falling on him near the Kiski River Campsite.

Thunderstorm Wind in INDIANA, PENNSYLVANIA
From 16-JUL-21 19:24:00 to 16-JUL-21 19:24:00 (EST-5)
Location: HORTONS
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Trees were reported down in the area of Porterfield Road.

Flash Flood in VENANGO, PENNSYLVANIA
From 16-JUL-21 20:02:00 to 16-JUL-21 21:30:00 (EST-5)
Location: POLK JCT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Multiple roads in the area had flooding issues.

Flash Flood in MERCER, PENNSYLVANIA
From 16-JUL-21 20:45:00 to 16-JUL-21 21:30:00 (EST-5)
Location: FREDONIA
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A water rescue was needed along Delaware Road for a car stranded in flood water.