A surface trough combined with moderate instability caused showers and thunderstorms to develop. There was enough instability for thunderstorms to produce damaging wind gusts and large hail.

Excessive Heat in SOUTHERN BALTIMORE, MARYLAND
From 18-JUL-12 12:00:00 to 18-JUL-12 15:00:00 (EST-5)
Reported by: AWOS

Heat indices were reported to be up to 113 degrees at the Maryland Science Center.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 18-JUL-12 14:13:00 to 18-JUL-12 14:13:00 (EST-5)
Location: MAPLEVILLE
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: State Official

A tree fell across the intersection of Boonsboro Mountain Road and Keadle Road.

Thunderstorm Wind in CARROLL, MARYLAND
From 18-JUL-12 14:30:00 to 18-JUL-12 14:30:00 (EST-5)
Location: TANEYTOWN
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: Emergency Manager

Large limbs and a power line was down due to thunderstorm wind gusts.

Thunderstorm Wind in FREDERICK, MARYLAND
From 18-JUL-12 14:30:00 to 18-JUL-12 14:30:00 (EST-5)
Location: LOYS
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: State Official

Trees were down along Old Frederick Road and Old Mill Road.

Thunderstorm Wind in FREDERICK, MARYLAND
From 18-JUL-12 14:30:00 to 18-JUL-12 14:30:00 (EST-5)
Location: CATOCTIN FURNACE
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: State Official

A tree was down on Kellys Store Road.

Thunderstorm Wind in FREDERICK, MARYLAND
From 18-JUL-12 14:50:00 to 18-JUL-12 14:50:00 (EST-5)
Location: NEW LONDON
Magnitude: 52.00 EG
Reported by: CoCoRaHS

Branches were down due to thunderstorm wind gusts.

Thunderstorm Wind in ANNE ARUNDEL, MARYLAND
From 18-JUL-12 15:45:00 to 18-JUL-12 15:45:00 (EST-5)
Location: ODENTON
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: Emergency Manager

Several trees were down due to thunderstorm wind gusts.

Thunderstorm Wind in ANNE ARUNDEL, MARYLAND
From 18-JUL-12 16:20:00 to 18-JUL-12 16:20:00 (EST-5)
Location: CAPE ST CLAIRE
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: Public

Two snapped trees and a large branch were down at a residence.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 18-JUL-12 14:24:00 to 18-JUL-12 14:24:00 (EST-5)
Location: MAPLEVILLE
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: 911 Call Center

Trees were down at Mill Point Road.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 18-JUL-12 14:30:00 to 18-JUL-12 14:30:00 (EST-5)
Location: PONDSVILLE
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: 911 Call Center

A tree was down along Crystal Falls Drive.

Thunderstorm Wind in CARROLL, MARYLAND
From 18-JUL-12 14:30:00 to 18-JUL-12 14:30:00 (EST-5)
Location: TYRONE
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: 911 Call Center

Large limbs were down due to thunderstorm wind gusts.

Thunderstorm Wind in CARROLL, MARYLAND
From 18-JUL-12 14:30:00 to 18-JUL-12 14:30:00 (EST-5)
Location: AVONDALE
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: State Official

Large limbs were down along MD 140.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 18-JUL-12 13:44:00 to 18-JUL-12 13:44:00 (EST-5)
Location: HAGERSTOWN
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: State Official

A tree fell onto a telephone pole along Wayside Avenue.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 18-JUL-12 13:45:00 to 18-JUL-12 13:45:00 (EST-5)
Location: HAGERSTOWN
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: State Official

A tree fell onto power lines along Locust Street.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 18-JUL-12 13:46:00 to 18-JUL-12 13:46:00 (EST-5)
Location: LINCOLN AVENUE
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: Fire Department/Rescue

Trees were down due to thunderstorm wind gusts.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 18-JUL-12 13:49:00 to 18-JUL-12 13:49:00 (EST-5)
Location: LINCOLN AVENUE
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: Fire Department/Rescue

A tree fell onto wires along Red Oak Drive.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 18-JUL-12 14:10:00 to 18-JUL-12 14:10:00 (EST-5)
Location: CHEWSVILLE
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: Fire Department/Rescue

A tree fell onto power lines Peacock Trail.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 18-JUL-12 14:20:00 to 18-JUL-12 14:20:00 (EST-5)
Location: LAPPANS
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: State Official

A tree fell onto power lines along Lappins road.