A strengthening line of showers and storms pushed into central Pennsylvania from the west during the afternoon of August 11, 2021. At the same time, discreet cells developed over the Lower Susquehanna Valley, well ahead of the main line. The greater Harrisburg area experienced multiple rounds of storms, generating localized flooding in many neighborhoods. Local rainfall data showed we received almost 2.5 inches, of which 1.4 and 1.65 inches fell in less than 30 minutes.

Flash Flood in DAUPHIN, PENNSYLVANIA
From 11-AUG-21 16:31:00 to 11-AUG-21 18:00:00 (EST-5)
Location: WEST END
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Flash flooding reported in downtown Harrisburg with reports of stranded vehicles.  One report specifically mentioned submerged vehicles on Market Street.
Video is available here:  https://www.youtube.com/watch?v=8DRmf5UiESA .

Thunderstorm Wind in LANCASTER, PENNSYLVANIA
From 11-AUG-21 16:42:00 to 11-AUG-21 16:42:00 (EST-5)
Location: (LNS)LANCASTER ARPT
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A severe thunderstorm produced a 58 mph wind gust at the Lancaster Airport ASOS (KLNS).

Thunderstorm Wind in HUNTINGDON, PENNSYLVANIA
From 11-AUG-21 14:24:00 to 11-AUG-21 14:24:00 (EST-5)
Location: ALEXANDRIA
Magnitude: 52.00 EG
Property damage: 9.00K
Crop damage: 0.00K
Reported by: 911 Call Center

A severe thunderstorm producing winds estimated near 60 mph knocked down multiple trees and wires south of Alexandria.

Thunderstorm Wind in HUNTINGDON, PENNSYLVANIA
From 11-AUG-21 14:22:00 to 11-AUG-21 14:22:00 (EST-5)
Location: HESSTON
Magnitude: 52.00 EG
Property damage: 4.00K
Crop damage: 0.00K
Reported by: 911 Call Center

A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires near Hesston.

Thunderstorm Wind in HUNTINGDON, PENNSYLVANIA
From 11-AUG-21 14:40:00 to 11-AUG-21 14:40:00 (EST-5)
Location: MILL CREEK
Magnitude: 52.00 EG
Property damage: 4.00K
Crop damage: 0.00K
Reported by: Public

A severe thunderstorm producing winds estimated near 60 mph knocked down trees and wires near Mill Creek.

Thunderstorm Wind in MIFFLIN, PENNSYLVANIA
From 11-AUG-21 15:02:00 to 11-AUG-21 15:02:00 (EST-5)
Location: MILROY
Magnitude: 52.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: 911 Call Center

A severe thunderstorm producing winds estimated near 60 mph knocked down trees across a road near Milroy.

Thunderstorm Wind in MIFFLIN, PENNSYLVANIA
From 11-AUG-21 15:05:00 to 11-AUG-21 15:05:00 (EST-5)
Location: BURNHAM
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: 911 Call Center

A severe thunderstorm producing winds estimated near 60 mph knocked down multiple trees near Burnham.

Thunderstorm Wind in DAUPHIN, PENNSYLVANIA
From 11-AUG-21 15:52:00 to 11-AUG-21 15:52:00 (EST-5)
Location: COLONIAL PARK
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

A severe thunderstorm producing winds estimated near 60 mph knocked down a tree onto a house near Colonial Park.

Thunderstorm Wind in DAUPHIN, PENNSYLVANIA
From 11-AUG-21 16:00:00 to 11-AUG-21 16:00:00 (EST-5)
Location: GRANTVILLE
Magnitude: 52.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

A severe thunderstorm producing winds estimated near 60 mph knocked down trees a road near Grantville.

Thunderstorm Wind in DAUPHIN, PENNSYLVANIA
From 11-AUG-21 15:46:00 to 11-AUG-21 15:46:00 (EST-5)
Location: SKYLINE VIEW
Magnitude: 52.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A severe thunderstorm producing winds estimated near 60 mph knocked down a tree across a road in West Hanover Township.

Thunderstorm Wind in LANCASTER, PENNSYLVANIA
From 11-AUG-21 16:55:00 to 11-AUG-21 16:55:00 (EST-5)
Location: LANCASTER JCT
Magnitude: 52.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: 911 Call Center

A severe thunderstorm producing winds estimated near 60 mph knocked down wires north of Landisville.

Thunderstorm Wind in CUMBERLAND, PENNSYLVANIA
From 11-AUG-21 15:49:00 to 11-AUG-21 15:49:00 (EST-5)
Location: NEW KINGSTOWN
Magnitude: 52.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A severe thunderstorm producing winds estimated near 60 mph knocked down wires onto two tractor trailers on the PA Turnpike west of Mechanicsburg.

Thunderstorm Wind in UNION, PENNSYLVANIA
From 11-AUG-21 15:45:00 to 11-AUG-21 15:45:00 (EST-5)
Location: COWAN
Magnitude: 52.00 EG
Property damage: 12.00K
Crop damage: 0.00K
Reported by: Utility Company

A severe thunderstorm producing winds estimated near 60 mph produced several reports of downed wires across western Union County.

Thunderstorm Wind in COLUMBIA, PENNSYLVANIA
From 11-AUG-21 16:45:00 to 11-AUG-21 16:45:00 (EST-5)
Location: EYERSGROVE
Magnitude: 52.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: 911 Call Center

A severe thunderstorm producing winds estimated near 60 mph knocked down trees on the 2000 block of Route 42.

Thunderstorm Wind in LANCASTER, PENNSYLVANIA
From 11-AUG-21 17:00:00 to 11-AUG-21 17:00:00 (EST-5)
Location: SWARTZVILLE
Magnitude: 52.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: 911 Call Center

A severe thunderstorm producing winds estimated near 60 mph knocked down wires near Adamstown.

Thunderstorm Wind in COLUMBIA, PENNSYLVANIA
From 11-AUG-21 16:56:00 to 11-AUG-21 16:56:00 (EST-5)
Location: BLOOMSBURG
Magnitude: 52.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: 911 Call Center

A severe thunderstorm producing winds estimated near 60 mph produced numerous reports of trees and wires down across Columbia County.

Thunderstorm Wind in LANCASTER, PENNSYLVANIA
From 11-AUG-21 17:14:00 to 11-AUG-21 17:14:00 (EST-5)
Location: NEW PROVIDENCE
Magnitude: 52.00 EG
Property damage: 12.00K
Crop damage: 0.00K
Reported by: Utility Company

A severe thunderstorm producing winds estimated near 60 mph produced several reports of wires down across southern Lancaster County.

Thunderstorm Wind in CENTRE, PENNSYLVANIA
From 11-AUG-21 14:55:00 to 11-AUG-21 14:55:00 (EST-5)
Location: CENTRE HALL ARPT
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

A severe thunderstorm producing winds estimated near 60 mph knocked down a tree onto wires near Centre Hall.

Thunderstorm Wind in DAUPHIN, PENNSYLVANIA
From 11-AUG-21 13:52:00 to 11-AUG-21 13:52:00 (EST-5)
Location: MIDDLETOWN
Magnitude: 52.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A severe thunderstorm producing winds estimated near 60 mph knocked down wires across a road near Middletown.