An upper-level ridge was centered over the southern Plains while an upper-level low was located over central Canada. A northwest flow between these two systems caused colder air aloft to move overhead. Warm and moist air at the surface combined with the colder air aloft to produce moderate amounts of instability. A pressure trough at the surface caused showers and thunderstorms to develop. Moderate instability caused some thunderstorms to produce damaging wind gusts and large hail.

Thunderstorm Wind in CALVERT, MARYLAND
From 01-AUG-11 18:40:00 to 01-AUG-11 18:40:00 (EST-5)
Location: NORTH BEACH
Magnitude: 61.00 EG
Property damage: 1.00K
Reported by: State Official

A tree was down near the intersection of MD 260 and G Street.

Thunderstorm Wind in CALVERT, MARYLAND
From 01-AUG-11 18:42:00 to 01-AUG-11 18:42:00 (EST-5)
Location: CHESAPEAKE BEACH
Magnitude: 61.00 EG
Property damage: 100.00K
Reported by: State Official

Trees were across Chesapeake Beach. A tree fell onto a house and another tree fell onto a car. There were two minor injuries due to the fallen trees.

Thunderstorm Wind in CALVERT, MARYLAND
From 01-AUG-11 18:43:00 to 01-AUG-11 18:43:00 (EST-5)
Location: NORTH BEACH
Magnitude: 56.00 EG
Property damage: 2.00K
Reported by: Public

Large limbs that were six inches in diameter were blown down. A large wooden fence was also blown down in North Beach.

Thunderstorm Wind in CALVERT, MARYLAND
From 01-AUG-11 18:45:00 to 01-AUG-11 18:45:00 (EST-5)
Location: NORTH BEACH
Magnitude: 63.00 MG
Reported by: Mesonet

A wind gust of 72 mph was measured at Chesapeake Beach.

Thunderstorm Wind in ANNE ARUNDEL, MARYLAND
From 01-AUG-11 17:35:00 to 01-AUG-11 17:35:00 (EST-5)
Location: NUTWELL
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: Public

Numerous poplar trees were torn off at the top.

Thunderstorm Wind in ANNE ARUNDEL, MARYLAND
From 01-AUG-11 17:35:00 to 01-AUG-11 17:35:00 (EST-5)
Location: LEITCH
Magnitude: 52.00 EG
Reported by: Public

Part of a large maple tree was blown down.

Thunderstorm Wind in ANNE ARUNDEL, MARYLAND
From 01-AUG-11 17:35:00 to 01-AUG-11 17:35:00 (EST-5)
Location: NUTWELL
Magnitude: 52.00 EG
Property damage: 5.00K
Reported by: Public

Several trees were down including large trees completely blocking Rockhold Creek Road.

Thunderstorm Wind in MONTGOMERY, MARYLAND
From 01-AUG-11 17:17:00 to 01-AUG-11 17:17:00 (EST-5)
Location: ASHTON
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: Public

A tree that was two feet in diameter was blocking the road.

Thunderstorm Wind in MONTGOMERY, MARYLAND
From 01-AUG-11 17:18:00 to 01-AUG-11 17:18:00 (EST-5)
Location: EDNOR
Magnitude: 52.00 EG
Reported by: Trained Spotter

Multiple small branches were down.

Hail in PRINCE GEORGE'S, MARYLAND
From 01-AUG-11 16:32:00 to 01-AUG-11 16:32:00 (EST-5)
Location: COLLEGE PARK
Magnitude: 1.00 
Reported by: Trained Spotter

Hail to the size of quarters was reported near College Park.

Thunderstorm Wind in PRINCE GEORGE'S, MARYLAND
From 01-AUG-11 16:32:00 to 01-AUG-11 16:32:00 (EST-5)
Location: COLLEGE PARK
Magnitude: 50.00 EG
Reported by: Trained Spotter

Tree branches that were two to three inches in diameter were blown down.

Thunderstorm Wind in PRINCE GEORGE'S, MARYLAND
From 01-AUG-11 16:38:00 to 01-AUG-11 16:38:00 (EST-5)
Location: BRANCHVILLE
Magnitude: 50.00 EG
Property damage: 1.00K
Reported by: Other Federal Agency

A large tree was down at Knights of Columbus in College Park.

Thunderstorm Wind in CHARLES, MARYLAND
From 01-AUG-11 16:53:00 to 01-AUG-11 16:53:00 (EST-5)
Location: BRYANS ROAD
Magnitude: 50.00 EG
Property damage: 1.00K
Reported by: State Official

A tree was down at the Safeway Store along Matthews Road.

Thunderstorm Wind in CHARLES, MARYLAND
From 01-AUG-11 16:51:00 to 01-AUG-11 16:51:00 (EST-5)
Location: MASON SPGS
Magnitude: 50.00 EG
Property damage: 3.00K
Reported by: State Official

Trees were down along Gilwell Place.

Thunderstorm Wind in CHARLES, MARYLAND
From 01-AUG-11 16:47:00 to 01-AUG-11 16:47:00 (EST-5)
Location: INDIAN HEAD
Magnitude: 50.00 EG
Property damage: 1.00K
Reported by: State Official

A tree was toppled over a vehicle along Oakside Lane.

Thunderstorm Wind in CHARLES, MARYLAND
From 01-AUG-11 17:03:00 to 01-AUG-11 17:03:00 (EST-5)
Location: MC CONCHIE
Magnitude: 50.00 EG
Property damage: 2.00K
Reported by: State Official

Trees were down near the intersection of Burch Road and Poorhouse Road.

Thunderstorm Wind in CHARLES, MARYLAND
From 01-AUG-11 17:03:00 to 01-AUG-11 17:03:00 (EST-5)
Location: MC CONCHIE
Magnitude: 50.00 EG
Property damage: 1.00K
Reported by: State Official

A tree was down along Ironsides Road.

Thunderstorm Wind in MONTGOMERY, MARYLAND
From 01-AUG-11 17:18:00 to 01-AUG-11 17:18:00 (EST-5)
Location: EDNOR
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: Trained Spotter

A tree that was twelve inches in diameter was blocking Tucker Lane.

Thunderstorm Wind in ANNE ARUNDEL, MARYLAND
From 01-AUG-11 17:32:00 to 01-AUG-11 17:32:00 (EST-5)
Location: DEALE
Magnitude: 50.00 EG
Reported by: Trained Spotter

Several tree branches were down.