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 LOUDOUN, VIRGINIA
From 01-AUG-11 15:00:00 to 01-AUG-11 15:00:00 (EST-5)
Location: LEESBURG MUNI
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Emergency Manager

Trees were down across southeastern Leesburg.

Thunderstorm Wind in LOUDOUN, VIRGINIA
From 01-AUG-11 16:03:00 to 01-AUG-11 16:03:00 (EST-5)
Location: LINCOLN
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: Emergency Manager

Trees were down along Hughesville Road.

Thunderstorm Wind in KING GEORGE, VIRGINIA
From 01-AUG-11 17:56:00 to 01-AUG-11 17:56:00 (EST-5)
Location: GERA
Magnitude: 52.00 EG
Reported by: Public

Multiple tree limbs that were four to five inches in diameter were down.

Hail in KING GEORGE, VIRGINIA
From 01-AUG-11 17:56:00 to 01-AUG-11 17:56:00 (EST-5)
Location: KING GEORGE
Magnitude: 1.00 
Reported by: Public

Quarter sized hail was reported near King George.

Thunderstorm Wind in KING GEORGE, VIRGINIA
From 01-AUG-11 18:22:00 to 01-AUG-11 18:22:00 (EST-5)
Location: LAMBS CREEK
Magnitude: 56.00 EG
Property damage: 5.00K
Reported by: Trained Spotter

Trees were snapped above the ground level near Birchwood Creek.

Thunderstorm Wind in KING GEORGE, VIRGINIA
From 01-AUG-11 17:56:00 to 01-AUG-11 17:56:00 (EST-5)
Location: GERA
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: Public

Several tree limbs that were a few inches in diameter were knocked down.

Thunderstorm Wind in KING GEORGE, VIRGINIA
From 01-AUG-11 17:56:00 to 01-AUG-11 17:56:00 (EST-5)
Location: GERA
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: Public

Multiple tree limbs that were four to five inches in diameter were blown down.

Hail in KING GEORGE, VIRGINIA
From 01-AUG-11 17:56:00 to 01-AUG-11 17:56:00 (EST-5)
Location: GERA
Magnitude: 1.00 
Reported by: Public

Quarter sized hail was estimated.

Hail in LOUDOUN, VIRGINIA
From 01-AUG-11 16:05:00 to 01-AUG-11 16:05:00 (EST-5)
Location: LINCOLN
Magnitude: 1.00 
Reported by: Public

Quarter sized hail was measured in Hughesville.

Hail in KING GEORGE, VIRGINIA
From 01-AUG-11 17:56:00 to 01-AUG-11 17:56:00 (EST-5)
Location: GERA
Magnitude: 1.00 
Reported by: Public

Quarter sized hail was estimated.

Thunderstorm Wind in LOUDOUN, VIRGINIA
From 01-AUG-11 16:03:00 to 01-AUG-11 16:03:00 (EST-5)
Location: LINCOLN
Magnitude: 52.00 EG
Property damage: 2.00K
Reported by: Public

Trees were down along Hughesville Road and adjacent proporties.

Thunderstorm Wind in FAIRFAX, VIRGINIA
From 01-AUG-11 16:07:00 to 01-AUG-11 16:07:00 (EST-5)
Location: ILDA
Magnitude: 50.00 EG
Property damage: 2.00K
Reported by: Emergency Manager

Trees were down at Wakefield Chapel Road and Little River Turnpike.

Thunderstorm Wind in FAIRFAX, VIRGINIA
From 01-AUG-11 16:12:00 to 01-AUG-11 16:12:00 (EST-5)
Location: RAVENSWORTH
Magnitude: 52.00 EG
Property damage: 5.00K
Reported by: Emergency Manager

Trees that were fourteen inches in diameter were down at Braddock Road and Ravensworth Road.

Thunderstorm Wind in LOUDOUN, VIRGINIA
From 01-AUG-11 17:05:00 to 01-AUG-11 17:05:00 (EST-5)
Location: LEESBURG MUNI
Magnitude: 52.00 EG
Reported by: State Official

A small plane was toppled at the Leesburg Executive Airport.

Thunderstorm Wind in FAIRFAX, VIRGINIA
From 01-AUG-11 16:15:00 to 01-AUG-11 16:15:00 (EST-5)
Location: FAIRFAX PARK
Magnitude: 50.00 EG
Reported by: Trained Spotter

Limbs that were five inches in diameter were down.

Thunderstorm Wind in LOUDOUN, VIRGINIA
From 01-AUG-11 17:31:00 to 01-AUG-11 17:31:00 (EST-5)
Location: PURCELLVILLE
Magnitude: 56.00 EG
Property damage: 1.00K
Reported by: State Official

A couple of trees were down along Hillsboro Road in Purcellville.

Thunderstorm Wind in LOUDOUN, VIRGINIA
From 01-AUG-11 17:35:00 to 01-AUG-11 17:35:00 (EST-5)
Location: PURCELLVILLE
Magnitude: 56.00 EG
Property damage: 3.00K
Reported by: State Official

Trees were down near the intersection of Purcellville Road and Allder School Road.

Thunderstorm Wind in KING GEORGE, VIRGINIA
From 01-AUG-11 17:45:00 to 01-AUG-11 17:45:00 (EST-5)
Location: FAIRVIEW BEACH
Magnitude: 61.00 EG
Property damage: 5.00K
Reported by: Trained Spotter

Trees up to ten inches in diameter were snapped thirty to forty feet up.

Thunderstorm Wind in KING GEORGE, VIRGINIA
From 01-AUG-11 17:46:00 to 01-AUG-11 17:46:00 (EST-5)
Location: WEEDONVILLE
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: Trained Spotter

Two trees were knocked down.

Thunderstorm Wind in LOUDOUN, VIRGINIA
From 01-AUG-11 17:45:00 to 01-AUG-11 17:45:00 (EST-5)
Location: RAEONIAN SPGS
Magnitude: 56.00 EG
Property damage: 3.00K
Reported by: State Official

Trees were down near Hamilton Station Road and Route 9.

Thunderstorm Wind in KING GEORGE, VIRGINIA
From 01-AUG-11 17:45:00 to 01-AUG-11 17:45:00 (EST-5)
Location: FAIRVIEW BEACH
Magnitude: 56.00 EG
Property damage: 50.00K
Reported by: Trained Spotter

Trees were on homes and many power lines were down.

Thunderstorm Wind in LOUDOUN, VIRGINIA
From 01-AUG-11 17:25:00 to 01-AUG-11 17:25:00 (EST-5)
Location: WATSON
Magnitude: 56.00 EG
Crop damage: 5.00K
Reported by: Public

Widespread wind damage to corn crop was reported.

Thunderstorm Wind in LOUDOUN, VIRGINIA
From 01-AUG-11 17:27:00 to 01-AUG-11 17:27:00 (EST-5)
Location: ALDIE
Magnitude: 52.00 EG
Property damage: 1.00K
Reported by: NWS Employee

A large tree was snapped near the Mt. Zion Cemetery.

Thunderstorm Wind in KING GEORGE, VIRGINIA
From 01-AUG-11 18:03:00 to 01-AUG-11 18:03:00 (EST-5)
Location: JERSEY
Magnitude: 56.00 EG
Property damage: 1.00K
Reported by: Trained Spotter

A tree was down on Route 625 east of Route 301.

Thunderstorm Wind in LOUDOUN, VIRGINIA
From 01-AUG-11 16:30:00 to 01-AUG-11 16:30:00 (EST-5)
Location: LENAH
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: State Official

Trees were down along Route 50 between Aldie and Arcola.