A cold frontal boundary pushed southeast from Lake Erie into a very moist and unstable air mass residing over central Pennsylvania. The frontal lift combined with high instability and adequate wind shear triggered numerous severe thunderstorms from the late morning through the afternoon. Multiple reports of thunderstorm wind damage and large hail were recorded.

Hail in CUMBERLAND, PENNSYLVANIA
From 18-JUL-12 12:45:00 to 18-JUL-12 12:45:00 (EST-5)
Location: CARLISLE
Magnitude: 0.75 
Reported by: Public

Hail in CUMBERLAND, PENNSYLVANIA
From 18-JUL-12 13:00:00 to 18-JUL-12 13:05:00 (EST-5)
Location: CARLISLE
Magnitude: 1.25 
Reported by: Public

Hail ranged in size from 1-1.25 inches in Carlisle.

Hail in DAUPHIN, PENNSYLVANIA
From 18-JUL-12 13:00:00 to 18-JUL-12 13:00:00 (EST-5)
Location: DAUPHIN
Magnitude: 1.75 
Reported by: Public

Hail in YORK, PENNSYLVANIA
From 18-JUL-12 13:45:00 to 18-JUL-12 13:45:00 (EST-5)
Location: DOVER
Magnitude: 1.75 
Reported by: Public

Hail in YORK, PENNSYLVANIA
From 18-JUL-12 14:00:00 to 18-JUL-12 14:00:00 (EST-5)
Location: STRINESTOWN
Magnitude: 0.75 
Reported by: Trained Spotter

Thunderstorm Wind in NORTHUMBERLAND, PENNSYLVANIA
From 18-JUL-12 11:50:00 to 18-JUL-12 11:50:00 (EST-5)
Location: HERNDON
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Trained Spotter

Thunderstorm winds estimated near 60 mph knocked down trees in Herndon.

Thunderstorm Wind in CUMBERLAND, PENNSYLVANIA
From 18-JUL-12 13:05:00 to 18-JUL-12 13:05:00 (EST-5)
Location: MIDDLESEX
Magnitude: 50.00 EG
Property damage: 1.00K
Reported by: Trained Spotter

Thunderstorm winds estimated near 60 mph knocked down large branches near Carlisle.

Thunderstorm Wind in FRANKLIN, PENNSYLVANIA
From 18-JUL-12 13:30:00 to 18-JUL-12 13:30:00 (EST-5)
Location: MARION
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Trained Spotter

Thunderstorm winds estimated near 60 mph knocked down trees in Marion.

Hail in YORK, PENNSYLVANIA
From 18-JUL-12 14:06:00 to 18-JUL-12 14:06:00 (EST-5)
Location: MANCHESTER
Magnitude: 0.75 
Reported by: Trained Spotter

Hail in ADAMS, PENNSYLVANIA
From 18-JUL-12 14:15:00 to 18-JUL-12 14:15:00 (EST-5)
Location: NEW OXFORD
Magnitude: 1.00 
Reported by: Trained Spotter

Thunderstorm Wind in DAUPHIN, PENNSYLVANIA
From 18-JUL-12 13:18:00 to 18-JUL-12 13:18:00 (EST-5)
Location: HARRISBURG
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Public

Thunderstorm winds estimated near 60 mph knocked down trees in the Harrisburg area.

Thunderstorm Wind in FRANKLIN, PENNSYLVANIA
From 18-JUL-12 13:27:00 to 18-JUL-12 13:27:00 (EST-5)
Location: CHAMBERSBURG
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Public

Thunderstorm winds estimated near 60 mph knocked down trees in Chambersburg.

Thunderstorm Wind in YORK, PENNSYLVANIA
From 18-JUL-12 13:30:00 to 18-JUL-12 13:30:00 (EST-5)
Location: DILLSBURG
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: State Official

Thunderstorm winds estimated near 60 mph knocked down trees in Carroll Township near Dillsburg.

Thunderstorm Wind in DAUPHIN, PENNSYLVANIA
From 18-JUL-12 13:34:00 to 18-JUL-12 13:34:00 (EST-5)
Location: PAXTONIA
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Public

Thunderstorm winds estimated near 60 mph knocked down trees near Paxtonia.

Thunderstorm Wind in FRANKLIN, PENNSYLVANIA
From 18-JUL-12 13:26:00 to 18-JUL-12 13:26:00 (EST-5)
Location: CHAMBERSBURG
Magnitude: 50.00 EG
Property damage: 7.50K
Reported by: State Official

Thunderstorm winds estimated near 60 mph knocked down trees along US 30 west of Chambersburg near St. Thomas. A few trees fell onto houses but the extent of structural damage was unknown.

Thunderstorm Wind in FRANKLIN, PENNSYLVANIA
From 18-JUL-12 14:00:00 to 18-JUL-12 14:00:00 (EST-5)
Location: WAYNECASTLE
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds estimated near 60 mph knocked down trees and utility wires near Waynesboro.

Thunderstorm Wind in SOMERSET, PENNSYLVANIA
From 18-JUL-12 14:55:00 to 18-JUL-12 14:55:00 (EST-5)
Location: FERRELTON
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: State Official

Thunderstorm winds estimated near 60 mph knocked down trees and wires near Boswell.

Thunderstorm Wind in ADAMS, PENNSYLVANIA
From 18-JUL-12 14:05:00 to 18-JUL-12 14:05:00 (EST-5)
Location: MCKNIGHTSTOWN
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Trained Spotter

Thunderstorm winds estimated near 60 mph snapped several 10-12 inch diameter trees near Cashtown.

Thunderstorm Wind in CAMBRIA, PENNSYLVANIA
From 18-JUL-12 14:55:00 to 18-JUL-12 14:55:00 (EST-5)
Location: SOUTHMONT
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm winds estimated near 60 mph knocked down trees and utility wires on SR 271 in Upper Yoder Township southwest of Johnstown.

Thunderstorm Wind in LANCASTER, PENNSYLVANIA
From 18-JUL-12 14:30:00 to 18-JUL-12 14:30:00 (EST-5)
Location: LITITZ
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Public

Thunderstorm winds estimated near 60 mph knocked down several large branches in Lititz.

Thunderstorm Wind in CLINTON, PENNSYLVANIA
From 18-JUL-12 14:39:00 to 18-JUL-12 14:39:00 (EST-5)
Location: CEDAR SPGS
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: State Official

Thunderstorm winds estimated near 60 mph knocked down trees near Mill Hall.

Thunderstorm Wind in CENTRE, PENNSYLVANIA
From 18-JUL-12 15:00:00 to 18-JUL-12 15:00:00 (EST-5)
Location: MILLHEIM
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Public

Thunderstorm winds estimated near 60 mph knocked down trees in Millheim.

Thunderstorm Wind in CENTRE, PENNSYLVANIA
From 18-JUL-12 14:50:00 to 18-JUL-12 14:50:00 (EST-5)
Location: AARONSBURG
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Public

Thunderstorm winds estimated near 60 mph knocked down trees in Aaronsburg.

Thunderstorm Wind in YORK, PENNSYLVANIA
From 18-JUL-12 14:30:00 to 18-JUL-12 14:30:00 (EST-5)
Location: YORK
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: State Official

Thunderstorm winds estimated near 60 mph knocked down utility wires in York Township.

Thunderstorm Wind in LANCASTER, PENNSYLVANIA
From 18-JUL-12 14:15:00 to 18-JUL-12 14:15:00 (EST-5)
Location: MANHEIM
Magnitude: 50.00 EG
Property damage: 2.50K
Crop damage: 0.00K
Reported by: State Official

Thunderstorm winds estimated near 60 mph knocked down large tree branches in Manheim.

Hail in PERRY, PENNSYLVANIA
From 18-JUL-12 12:30:00 to 18-JUL-12 12:30:00 (EST-5)
Location: SHERMANS DALE
Magnitude: 1.25 
Reported by: Public

Hail in HUNTINGDON, PENNSYLVANIA
From 18-JUL-12 12:31:00 to 18-JUL-12 12:31:00 (EST-5)
Location: BROAD TOP CITY
Magnitude: 1.00 
Reported by: Public

Thunderstorm Wind in CUMBERLAND, PENNSYLVANIA
From 18-JUL-12 13:10:00 to 18-JUL-12 13:10:00 (EST-5)
Location: GETTYSBURG JCT
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: State Official

Thunderstorm winds estimated near 60 mph knocked down large trees Carlisle Springs.