After a significant heatwave, a cold front approached the mid-Atlantic on July 1, 2021. A potent mid-level trough was also digging southward through southern Ontario and into the Great Lakes region, and a strong upper level jet streak was present downstream the trough axis, over the interior mid-Atlantic and northern New England. This strong upper level forcing combined with the approaching front and a lingering warm, moist air mass ahead of it caused widespread thunderstorm development on July 1. Storms occurred almost exclusively south of Interstate 78, in the environment of best instability. A number of storms became severe, taking the form of mainly linear and multi-cellular clusters but with some embedded supercellular characteristics. Straight line wind damage was the primary hazard, with a number of reports of downed trees and power outages due to winds. With the cold front remaining to the west, some storm activity continued into the overnight, but storm coverage and intensity gradually waned with the loss of daytime heating and the overturning of the atmosphere from earlier storms.

Thunderstorm Wind in MONTGOMERY, PENNSYLVANIA
From 01-JUL-21 14:23:00 to 01-JUL-21 14:23:00 (EST-5)
Location: GILBERTSVILLE
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

An mPing report of tree limbs or power lines down near Route 100. Time estimated from radar.

Thunderstorm Wind in PHILADELPHIA, PENNSYLVANIA
From 01-JUL-21 15:48:00 to 01-JUL-21 15:48:00 (EST-5)
Location: TACONY
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

An mPing report of tree damage near Jackson St. Time estimated from radar.

Thunderstorm Wind in CHESTER, PENNSYLVANIA
From 01-JUL-21 14:27:00 to 01-JUL-21 14:27:00 (EST-5)
Location: DOWNINGTOWN
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

A tree was downed on Beaver Run Rd. Time estimated from radar.

Thunderstorm Wind in CHESTER, PENNSYLVANIA
From 01-JUL-21 14:26:00 to 01-JUL-21 14:26:00 (EST-5)
Location: ROCK RUN
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Utility Company

Trees and wires were downed near Valley Station Rd in Coatesville. Time estimated from radar.

Thunderstorm Wind in CHESTER, PENNSYLVANIA
From 01-JUL-21 14:47:00 to 01-JUL-21 14:47:00 (EST-5)
Location: HARMONY HILL
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Wires were downed near Paradise Valley Nature area in Downingtown. Time estimated from radar.

Thunderstorm Wind in CHESTER, PENNSYLVANIA
From 01-JUL-21 15:00:00 to 01-JUL-21 15:00:00 (EST-5)
Location: FIVE PTS
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Utility Company

Trees and wires were downed on Marshall Bridge Rd in Kennett Square. Time estimated from radar.

Thunderstorm Wind in BUCKS, PENNSYLVANIA
From 01-JUL-21 15:50:00 to 01-JUL-21 15:50:00 (EST-5)
Location: LANGHORNE TERRACE
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

A tree was downed on US-1. Time estimated from radar.

Thunderstorm Wind in BUCKS, PENNSYLVANIA
From 01-JUL-21 15:59:00 to 01-JUL-21 15:59:00 (EST-5)
Location: FAIRLESS HILLS
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Utility Company

Several reports of downed power lines near Fairless Hills. Time estimated from radar.

Thunderstorm Wind in LEHIGH, PENNSYLVANIA
From 01-JUL-21 14:21:00 to 01-JUL-21 14:21:00 (EST-5)
Location: HOSENSACK
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Utility Company

Wires were downed near Elm Rd. Time estimated from radar.

Thunderstorm Wind in CHESTER, PENNSYLVANIA
From 01-JUL-21 14:31:00 to 01-JUL-21 14:31:00 (EST-5)
Location: CHESTER SPGS
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Utility Company

Wires were downed near Horseshoe Trail. Time estimated from radar.

Thunderstorm Wind in BUCKS, PENNSYLVANIA
From 01-JUL-21 15:53:00 to 01-JUL-21 15:53:00 (EST-5)
Location: LEVITTOWN
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Utility Company

There were numerous reports of downed tree limbs and wires in Levittown. Radar indicated some rotation with this storm, prompting a Tornado Warning. However, damage was consistent with straight line winds. Time estimated from radar.

Thunderstorm Wind in CHESTER, PENNSYLVANIA
From 01-JUL-21 14:13:00 to 01-JUL-21 14:13:00 (EST-5)
Location: COMPASS
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

A tree was downed on Lammey Rd. Time estimated from radar.

Thunderstorm Wind in CHESTER, PENNSYLVANIA
From 01-JUL-21 14:21:00 to 01-JUL-21 14:21:00 (EST-5)
Location: REECEVILLE
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

A tree was downed on Fisherville Rd. Time estimated from radar.

Thunderstorm Wind in CHESTER, PENNSYLVANIA
From 01-JUL-21 14:51:00 to 01-JUL-21 14:51:00 (EST-5)
Location: PERKIOMEN JCT
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Utility Company

Several reports of downed tree limbs and wires near Valley Forge and Phoenixville. Time estimated from radar.

Thunderstorm Wind in MONTGOMERY, PENNSYLVANIA
From 01-JUL-21 15:30:00 to 01-JUL-21 15:30:00 (EST-5)
Location: JENKINTOWN
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

A tree and wires were downed near the intersection of Washington Ln and Pepper Rd. Time estimated from radar.

Thunderstorm Wind in MONTGOMERY, PENNSYLVANIA
From 01-JUL-21 15:12:00 to 01-JUL-21 15:12:00 (EST-5)
Location: HARMONVILLE
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

Tree limbs were downed on Joshua Rd near Cedar Grove Rd. Time estimated from radar.

Thunderstorm Wind in BUCKS, PENNSYLVANIA
From 01-JUL-21 15:19:00 to 01-JUL-21 15:19:00 (EST-5)
Location: EDISON
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Trees and wires were downed near Turk Rd in Doylestown. Time estimated from radar.

Thunderstorm Wind in MONTGOMERY, PENNSYLVANIA
From 01-JUL-21 14:59:00 to 01-JUL-21 14:59:00 (EST-5)
Location: WEST PT
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Utility Company

Trees and wires were downed near Garfield Park in Lansdale. Time estimated from radar.