Strong to severe thunderstorms developed over the upper Ohio Valley during the day on May 31st ahead of surface low pressure that would cross the region in the evening. With moderate instability and shear, several storms produced severe wind damage. In addition, where shear was enhanced near a stationary boundary, a brief EF-0 tornado touched down in Hermitage, Mercer county. Damage occurred at and around the Sheetz in Hermitage and a truck was flipped onto it's side in the parking lot.

Hail in JEFFERSON, PENNSYLVANIA
From 31-MAY-15 10:35:00 to 31-MAY-15 10:35:00 (EST-5)
Location: KAHLETOWN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in CLARION, PENNSYLVANIA
From 31-MAY-15 13:08:00 to 31-MAY-15 13:08:00 (EST-5)
Location: SCOTCH HILL
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CLARION, PENNSYLVANIA
From 31-MAY-15 10:20:00 to 31-MAY-15 10:20:00 (EST-5)
Location: SCOTCH HILL
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Park/Forest Service

Flood in BEAVER, PENNSYLVANIA
From 31-MAY-15 16:28:00 to 31-MAY-15 16:28:00 (EST-5)
Location: FALLSTON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

State official reported a mud slide in the area of 501 Constitution Boulevard in Patterson township. Police department on the scene reported that Debris is partially closing route 51.

Flood in MERCER, PENNSYLVANIA
From 31-MAY-15 17:15:00 to 31-MAY-15 21:35:00 (EST-5)
Location: GREENVILLE MUNI ARPT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

State official reported that route 18 in Sugar Grove Township was closed due to flooding.

Flood in MERCER, PENNSYLVANIA
From 31-MAY-15 18:05:00 to 31-MAY-15 21:35:00 (EST-5)
Location: JAMESTOWN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

State official reported that route 58 between Depot Road and Scipio Road in the town of Jamestown was closed due to flooding and damage to the roadway.

Hail in JEFFERSON, PENNSYLVANIA
From 31-MAY-15 13:47:00 to 31-MAY-15 13:47:00 (EST-5)
Location: KAHLETOWN
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in CLARION, PENNSYLVANIA
From 31-MAY-15 10:26:00 to 31-MAY-15 10:26:00 (EST-5)
Location: SCOTCH HILL
Magnitude: 50.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Post Office

Local post office reported trees down.

Tornado in MERCER, PENNSYLVANIA
From 31-MAY-15 15:00:00 to 31-MAY-15 15:02:00 (EST-5)
Location: WHEATLAND
Tornado F-scale: EF0
Property damage: 20.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A brief EF-0 tornado was confirmed, with maximum wind speeds of 80mph, after a survey of damage and review of available radar data and security camera footage. The most significant damage occurred near where the tornado began, at the Sheetz gas station at the corner of Route 18 and 518. At this location, part of a station canopy was removed and dispersed downwind to the north. Numerous panels of a wood fence were blown from north to south and the wind was observed on camera footage to lift the rear of a pickup truck, rotating it over 90 degrees before depositing it on it's side. Nearby, many large trees and branches were snapped, with  one tree uprooted and blown toward the northwest. One home experienced loss of shingles over a large portion of it's roof.
The damage path continued northeastward and consisted primarily of snapped and uprooted trees. Damage became much sparser with time, and seemed to end just north of Sample Road. The path length was just over a mile long and max width was 250 yards.

Thunderstorm Wind in BEAVER, PENNSYLVANIA
From 31-MAY-15 15:11:00 to 31-MAY-15 15:11:00 (EST-5)
Location: FAIRVIEW
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Department of Highways

State department of transportation reported trees down on state Route 168.

Thunderstorm Wind in LAWRENCE, PENNSYLVANIA
From 31-MAY-15 15:34:00 to 31-MAY-15 15:34:00 (EST-5)
Location: ELLWOOD CITY
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Department of Highways

State department of transportation reported trees down on State Route 288.

Thunderstorm Wind in BUTLER, PENNSYLVANIA
From 31-MAY-15 15:55:00 to 31-MAY-15 15:55:00 (EST-5)
Location: HARMONY
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Department of Highways

State department of transportation reported trees down near Zelienople.

Thunderstorm Wind in GREENE, PENNSYLVANIA
From 31-MAY-15 16:42:00 to 31-MAY-15 16:42:00 (EST-5)
Location: RUTAN
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Public

The public reported numerous trees snapped and uprooted across two properties at the intersection of Maranda Run Road and Jacob's run Road. One home sustained partial siding damage.

Flood in MERCER, PENNSYLVANIA
From 31-MAY-15 12:21:00 to 31-MAY-15 14:21:00 (EST-5)
Location: FARRELL
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Picture posted on social media shows Connelly Blvd flooded in a low spot, with water up to the hood of some cares.