An unseasonably strong weather system affected the mid-Atlantic on April 30, 2021. A cold front moved through the region in the predawn hours of April 30, associated with low pressure moving into coastal New England. An upper level disturbance and a secondary cold front then approached late in the day on the 30th. This system interacted with the departing low pressure over New England, causing that low to rapidly intensify as it began moving towards the Canadian maritimes. With high pressure over the Midwest, this led to a very strong pressure gradient over the mid-Atlantic. Combined with strong dynamics associated with the secondary cold front, a lengthy period of windy conditions developed for much of the day on the 30th. Widespread wind gusts of 45 to 55 mph, with some gusts of 60 to 65 mph, occurred. This, combined with many trees across the region already bearing leaves, led to numerous instances of tree damage and power outages across the region. Scattered showers associated with the secondary front also helped to locally enhance wind damage. Winds finally began to decrease by the night of the 30th as the gradient gradually weakened.

High Wind in MONROE, PENNSYLVANIA
From 30-APR-21 15:00:00 to 30-APR-21 23:00:00 (EST-5)
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: Department of Highways

Some downed trees and power lines were reported, including on Kunkletown Rd.

High Wind in EASTERN MONTGOMERY, PENNSYLVANIA
From 30-APR-21 13:00:00 to 30-APR-21 21:00:00 (EST-5)
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

Numerous downed trees and wires were reported. A trained spotter in King of Prussia reported a 55 mph measured gust.

High Wind in WESTERN MONTGOMERY, PENNSYLVANIA
From 30-APR-21 13:00:00 to 30-APR-21 21:00:00 (EST-5)
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Numerous downed trees and wires were reported. Measured gusts of 50 to 60 mph were reported in surrounding areas.

High Wind in WESTERN CHESTER, PENNSYLVANIA
From 30-APR-21 12:00:00 to 30-APR-21 20:00:00 (EST-5)
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: Department of Highways

Numerous downed trees and wires were reported. Measured gusts of 50 to 60 mph were reported in surrounding areas.

High Wind in CARBON, PENNSYLVANIA
From 30-APR-21 15:00:00 to 30-APR-21 22:00:00 (EST-5)
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: Department of Highways

Multiple reports of downed trees and wires in the county, including on PA-54 and Lentz Trail.

High Wind in NORTHAMPTON, PENNSYLVANIA
From 30-APR-21 15:00:00 to 30-APR-21 22:00:00 (EST-5)
Magnitude: 53.00 MG
Crop damage: 0.00K
Reported by: Trained Spotter

Damage reports included a snapped telephone pole on Richmond Rd (via a trained spotter) and downed trees and wires on Stones Crossing Rd and William Penn Hwy. The trained spotter in Forks Twp also reported a measured 61 mph wind gust.

High Wind in LEHIGH, PENNSYLVANIA
From 30-APR-21 15:30:00 to 30-APR-21 21:00:00 (EST-5)
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: Department of Highways

Downed trees and wires were reported near downtown Allentown, as well as on Mertztown Rd and on PA-863. A trained spotter in Whitehall Twp measured a 51 mph wind gust.

High Wind in BERKS, PENNSYLVANIA
From 30-APR-21 12:00:00 to 30-APR-21 17:00:00 (EST-5)
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: Department of Highways

Trees and wires were reported down including on Rohrbach Rd, Manatawany Rd, and US-222. The Reading Regional Airport ASOS also recorded a 54 mph measured gust.

High Wind in EASTERN CHESTER, PENNSYLVANIA
From 30-APR-21 12:00:00 to 30-APR-21 20:00:00 (EST-5)
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: Department of Highways

Numerous downed trees and wires were reported. Measured gusts of 50 to 60 mph were reported in surrounding areas.

High Wind in PHILADELPHIA, PENNSYLVANIA
From 30-APR-21 13:00:00 to 30-APR-21 19:00:00 (EST-5)
Magnitude: 50.00 MG
Crop damage: 0.00K
Reported by: Mesonet

A Pennsylvania DOT gauge reported a 58 mph measured gust. A couple of downed trees and power outages were reported.

High Wind in DELAWARE, PENNSYLVANIA
From 30-APR-21 13:00:00 to 30-APR-21 19:00:00 (EST-5)
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported a large tree down on Macdade Blvd between the southbound I-476 exit ramp and Bullens Ln. A couple of other tree damage and power outage reports were received, and measured wind gusts to nearly 60 mph were reported nearby.

High Wind in UPPER BUCKS, PENNSYLVANIA
From 30-APR-21 15:00:00 to 30-APR-21 20:00:00 (EST-5)
Magnitude: 50.00 EG
Crop damage: 0.00K
Reported by: Public

Tree damage and power outages were reported. A highest measured gust of 51 mph was measured in Nockamixon.

High Wind in LOWER BUCKS, PENNSYLVANIA
From 30-APR-21 15:00:00 to 30-APR-21 20:00:00 (EST-5)
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Tree damage and power outages were reported, with measured gusts of 50 to 55 mph in surrounding areas.