A cold front passed through on the 17th, and southwest winds ahead of the boundary led to an unstable atmosphere. The instability combined with the lift from the cold front to produce severe thunderstorms.

Thunderstorm Wind in HARFORD, MARYLAND
From 17-JUL-18 13:47:00 to 17-JUL-18 13:47:00 (EST-5)
Location: ABINGDON
Magnitude: 50.00 EG
Reported by: 911 Call Center

A tree was down on wires.

Thunderstorm Wind in HARFORD, MARYLAND
From 17-JUL-18 14:11:00 to 17-JUL-18 14:11:00 (EST-5)
Location: CHURCHVILLE
Magnitude: 50.00 EG
Reported by: 911 Call Center

A tree was down on wires along State Route 136.

Thunderstorm Wind in PRINCE GEORGE'S, MARYLAND
From 17-JUL-18 14:42:00 to 17-JUL-18 14:42:00 (EST-5)
Location: TEMPLE HILLS
Magnitude: 50.00 EG
Reported by: Trained Spotter

A tree six inches in diameter was down blocking a lane of traffic on Brinkley Road.

Thunderstorm Wind in CALVERT, MARYLAND
From 17-JUL-18 15:17:00 to 17-JUL-18 15:17:00 (EST-5)
Location: CHESAPEAKE BEACH
Magnitude: 50.00 EG
Reported by: 911 Call Center

A tree was down in Chesapeake Beach.

Thunderstorm Wind in CALVERT, MARYLAND
From 17-JUL-18 15:38:00 to 17-JUL-18 15:38:00 (EST-5)
Location: PORT REPUBLIC
Magnitude: 50.00 EG
Reported by: 911 Call Center

There were several reports of trees down in the Port Republic Area.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 17-JUL-18 19:00:00 to 17-JUL-18 19:00:00 (EST-5)
Location: FOUNTAIN HEAD
Magnitude: 50.00 EG
Reported by: 911 Call Center

A downed tree on wires was located near the 1000 Block of Columbia Road.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 17-JUL-18 19:08:00 to 17-JUL-18 19:08:00 (EST-5)
Location: FIERY SIDING
Magnitude: 50.00 EG
Reported by: 911 Call Center

A downed tree was on wires near the 10000 Block of Garis Shop Road.

Thunderstorm Wind in FREDERICK, MARYLAND
From 17-JUL-18 19:18:00 to 17-JUL-18 19:18:00 (EST-5)
Location: ELLERTON
Magnitude: 50.00 EG
Reported by: Department of Highways

A tree was down on Mt. Tabor Road and there were downed trees near the crossroad of Pleasant Walk Road and Route 40.

Thunderstorm Wind in FREDERICK, MARYLAND
From 17-JUL-18 19:23:00 to 17-JUL-18 19:23:00 (EST-5)
Location: HARMONY
Magnitude: 50.00 EG
Reported by: County Official

Two trees were down at a residence and there were downed trees near the crossroad of Brethren Church Road and Route 40.

Thunderstorm Wind in FREDERICK, MARYLAND
From 17-JUL-18 19:27:00 to 17-JUL-18 19:27:00 (EST-5)
Location: HARMONY
Magnitude: 50.00 EG
Reported by: Department of Highways

A tree was down near the intersection of Hollow Road and Hawbottom Road.

Thunderstorm Wind in FREDERICK, MARYLAND
From 17-JUL-18 19:35:00 to 17-JUL-18 19:35:00 (EST-5)
Location: BRADDOCK HGTS
Magnitude: 50.00 EG
Reported by: 911 Call Center

There were downed trees near the 4000 Block of Cherry Lane.

Thunderstorm Wind in FREDERICK, MARYLAND
From 17-JUL-18 19:37:00 to 17-JUL-18 19:37:00 (EST-5)
Location: FEAGAVILLE
Magnitude: 50.00 EG
Reported by: 911 Call Center

There were downed trees near the crossroad of Mount Phillip Road and Mount Zion Road.

Thunderstorm Wind in FREDERICK, MARYLAND
From 17-JUL-18 19:51:00 to 17-JUL-18 19:51:00 (EST-5)
Location: URBANA
Magnitude: 50.00 EG
Reported by: Department of Highways

Multiple trees and branches were down in roadways in the Urbana Area.

Thunderstorm Wind in FREDERICK, MARYLAND
From 17-JUL-18 19:54:00 to 17-JUL-18 19:54:00 (EST-5)
Location: MONROVIA
Magnitude: 50.00 EG
Reported by: 911 Call Center

A downed tree fell into a house in Monrovia.

Thunderstorm Wind in FREDERICK, MARYLAND
From 17-JUL-18 19:15:00 to 17-JUL-18 19:15:00 (EST-5)
Location: WOLFSVILLE
Magnitude: 50.00 EG
Reported by: Department of Highways

A tree was down near the intersection off Pleasant Walk Road and Easterday Road.