A fairly weak mid-level shortwave and an associated surface low pressure crossed the upper Ohio Valley on August 15th.  Dewpoints in the mid to upper 60s combined with relatively cool air aloft to yield mean layer CAPE values of up to 2000 J/kg.  Deep layer shear was sufficient for the development of discrete storms, although low-level shear was not supportive of a tornado threat.
Storms began to form just after noon and continued into the early evening hours, with the strongest storms seen between 2 PM and 6 PM.  Several marginally severe hail reports were received, along with many instances of wind damage.  A couple of homes were impacted by fallen trees in Allegheny County, while the last significant storm of the day produced widespread tree damage in two Mercer County townships.

Thunderstorm Wind in ARMSTRONG, PENNSYLVANIA
From 15-AUG-19 14:45:00 to 15-AUG-19 14:45:00 (EST-5)
Location: WEST KITTANNING
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The county emergency manager reported trees and power lines down on Queen Street.

Hail in LAWRENCE, PENNSYLVANIA
From 15-AUG-19 16:01:00 to 15-AUG-19 16:01:00 (EST-5)
Location: MC OASLIN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Hail in MERCER, PENNSYLVANIA
From 15-AUG-19 13:40:00 to 15-AUG-19 13:40:00 (EST-5)
Location: STONEBORO
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Thunderstorm Wind in ALLEGHENY, PENNSYLVANIA
From 15-AUG-19 13:55:00 to 15-AUG-19 13:55:00 (EST-5)
Location: BOWER HILL
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The county emergency manager reported that a tree fell on a house and ruptured a gas line.

Thunderstorm Wind in ALLEGHENY, PENNSYLVANIA
From 15-AUG-19 13:58:00 to 15-AUG-19 13:58:00 (EST-5)
Location: ROOK
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

The local fire department reported that a tree fell on a house.

Hail in MERCER, PENNSYLVANIA
From 15-AUG-19 17:19:00 to 15-AUG-19 17:19:00 (EST-5)
Location: KREMIS
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in MERCER, PENNSYLVANIA
From 15-AUG-19 17:19:00 to 15-AUG-19 17:19:00 (EST-5)
Location: DELEWARE GROVE
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: 911 Call Center

County 911 officials reported that multiple trees and power lines were blown down across Jefferson Township.

Thunderstorm Wind in MERCER, PENNSYLVANIA
From 15-AUG-19 17:26:00 to 15-AUG-19 17:26:00 (EST-5)
Location: FREDONIA
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Multiple trees and power lines were blown down across Delaware Township according to county 911 officials.

Thunderstorm Wind in INDIANA, PENNSYLVANIA
From 15-AUG-19 22:59:00 to 15-AUG-19 22:59:00 (EST-5)
Location: HEILWOOD
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A member of the public reported that large limbs were blown down along Staff Street and near the post office.

Thunderstorm Wind in ALLEGHENY, PENNSYLVANIA
From 15-AUG-19 14:03:00 to 15-AUG-19 14:03:00 (EST-5)
Location: CASTLE SHANNON
Magnitude: 50.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The county emergency manager reported that two trees were blown down and blocking Fort Couch Road.

Thunderstorm Wind in INDIANA, PENNSYLVANIA
From 15-AUG-19 14:41:00 to 15-AUG-19 14:41:00 (EST-5)
Location: CLUNE
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: State Official

County 911 officials stated that a number of trees and power lines were blown down across Young Township.

Thunderstorm Wind in ALLEGHENY, PENNSYLVANIA
From 15-AUG-19 14:12:00 to 15-AUG-19 14:12:00 (EST-5)
Location: BRENTWOOD
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The county emergency manager reported that trees and power lines were blown down.

Thunderstorm Wind in INDIANA, PENNSYLVANIA
From 15-AUG-19 14:30:00 to 15-AUG-19 14:30:00 (EST-5)
Location: ISELIN
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The county emergency manager reported downed trees and power lines.

Thunderstorm Wind in INDIANA, PENNSYLVANIA
From 15-AUG-19 14:41:00 to 15-AUG-19 14:41:00 (EST-5)
Location: CLARKSBURG
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: 911 Call Center

County 911 officials reported that a number of trees and power lines were blown down across Young Township.

Hail in LAWRENCE, PENNSYLVANIA
From 15-AUG-19 16:06:00 to 15-AUG-19 16:06:00 (EST-5)
Location: EASTBROOK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Hail in ALLEGHENY, PENNSYLVANIA
From 15-AUG-19 14:35:00 to 15-AUG-19 14:35:00 (EST-5)
Location: WHITE OAK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in WESTMORELAND, PENNSYLVANIA
From 15-AUG-19 14:40:00 to 15-AUG-19 14:40:00 (EST-5)
Location: MARKVUE MANOR
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The county emergency manager reports that trees and power lines were blown down on Park Hill Road.

Hail in MERCER, PENNSYLVANIA
From 15-AUG-19 13:07:00 to 15-AUG-19 13:07:00 (EST-5)
Location: MILBURN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in WESTMORELAND, PENNSYLVANIA
From 15-AUG-19 13:30:00 to 15-AUG-19 13:30:00 (EST-5)
Location: SARDIS
Magnitude: 50.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

A local fire department stated that trees were blown down near Wallace and Sardis Roads.