Southwest flow kept a cold front over Southern New England for a prolonged period of time.  Coupled with an approaching shortwave, this created enough lift, instability, and moisture to produce strong to severe thunderstorms.  These storms produced both large hail and damaging winds with hail up to quarter size and numerous downed trees.

Hail in WORCESTER, MASSACHUSETTS
From 19-AUG-11 13:40:00 to 19-AUG-11 13:40:00 (EST-5)
Location: HOLDEN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in NORFOLK, MASSACHUSETTS
From 19-AUG-11 13:57:00 to 19-AUG-11 13:57:00 (EST-5)
Location: MEDWAY
Magnitude: 50.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Large branches on Massasoit Street were downed by thunderstorm winds.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 19-AUG-11 14:18:00 to 19-AUG-11 14:18:00 (EST-5)
Location: NEWTON CENTER
Magnitude: 50.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A tree at the intersection of Prince and Sewall Streets was downed by thunderstorm winds.

Thunderstorm Wind in NORFOLK, MASSACHUSETTS
From 19-AUG-11 14:19:00 to 19-AUG-11 14:19:00 (EST-5)
Location: DOVER
Magnitude: 50.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Large limbs and wires throughout town were downed by thunderstorm winds, including on Center Street.

Thunderstorm Wind in NORFOLK, MASSACHUSETTS
From 19-AUG-11 14:19:00 to 19-AUG-11 14:19:00 (EST-5)
Location: BROOKLINE
Magnitude: 50.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Several large branches near Hellenic College, Lars Anderson Park, and on Park and Avon Streets were downed by thunderstorm winds.

Hail in FRANKLIN, MASSACHUSETTS
From 19-AUG-11 14:20:00 to 19-AUG-11 14:20:00 (EST-5)
Location: ROWE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Quarter size hail fell on Zoar Road.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 19-AUG-11 14:25:00 to 19-AUG-11 14:25:00 (EST-5)
Location: NORTH SOMMERVILLE
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Trees on Walden Street were downed by thunderstorm winds.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 19-AUG-11 14:25:00 to 19-AUG-11 14:25:00 (EST-5)
Location: CAMBRIDGE
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Trees and wires on Belmont and Windsor Streets were downed by thunderstorm winds.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 19-AUG-11 14:25:00 to 19-AUG-11 14:25:00 (EST-5)
Location: WEST EVERETT
Magnitude: 50.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Trees and power lines on Waite Street were downed by thunderstorm winds.

Thunderstorm Wind in SUFFOLK, MASSACHUSETTS
From 19-AUG-11 14:25:00 to 19-AUG-11 14:25:00 (EST-5)
Location: BOSTON
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Trees on Park and Dartmouth Streets were downed by thunderstorm winds, blocking those streets.

Hail in SUFFOLK, MASSACHUSETTS
From 19-AUG-11 14:26:00 to 19-AUG-11 14:26:00 (EST-5)
Location: CHARLESTOWN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in WORCESTER, MASSACHUSETTS
From 19-AUG-11 14:28:00 to 19-AUG-11 14:28:00 (EST-5)
Location: HOLDEN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in SUFFOLK, MASSACHUSETTS
From 19-AUG-11 14:30:00 to 19-AUG-11 14:30:00 (EST-5)
Location: BOSTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Quarter size hail fell in the Back Bay section of Boston.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 19-AUG-11 14:40:00 to 19-AUG-11 14:40:00 (EST-5)
Location: ACTON
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Numerous trees throughout town were downed by thunderstorm winds.

Hail in ESSEX, MASSACHUSETTS
From 19-AUG-11 14:49:00 to 19-AUG-11 14:49:00 (EST-5)
Location: LYNN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in ESSEX, MASSACHUSETTS
From 19-AUG-11 14:50:00 to 19-AUG-11 14:50:00 (EST-5)
Location: SALEM CGAS
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in ESSEX, MASSACHUSETTS
From 19-AUG-11 14:50:00 to 19-AUG-11 14:50:00 (EST-5)
Location: LYNN
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Trees on Lynn Shore Drive were downed by thunderstorm winds.

Hail in MIDDLESEX, MASSACHUSETTS
From 19-AUG-11 14:57:00 to 19-AUG-11 14:57:00 (EST-5)
Location: WEST CHELMSFORD
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 19-AUG-11 14:57:00 to 19-AUG-11 14:57:00 (EST-5)
Location: WEST CHELMSFORD
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Several trees were downed by thunderstorm winds.

Thunderstorm Wind in ESSEX, MASSACHUSETTS
From 19-AUG-11 15:04:00 to 19-AUG-11 15:09:00 (EST-5)
Location: SALEM CGAS
Magnitude: 50.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Trees on Broadway, Wisteria Street, and Raymond Avenue were downed by thunderstorm winds.  One of these trees fell on a house on Broadway.  Another fell on a car on Wisteria Street.

Thunderstorm Wind in ESSEX, MASSACHUSETTS
From 19-AUG-11 15:08:00 to 19-AUG-11 15:08:00 (EST-5)
Location: MARBLEHEAD
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A large limb and wires on Ruby Street were downed by thunderstorm winds.

Hail in HAMPSHIRE, MASSACHUSETTS
From 19-AUG-11 16:01:00 to 19-AUG-11 16:01:00 (EST-5)
Location: PLAINFIELD
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in HAMPSHIRE, MASSACHUSETTS
From 19-AUG-11 16:05:00 to 19-AUG-11 16:05:00 (EST-5)
Location: CUMMINGTON
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Trees and wires on Fairgrounds Road were downed by thunderstorm winds.

Thunderstorm Wind in HAMPSHIRE, MASSACHUSETTS
From 19-AUG-11 16:20:00 to 19-AUG-11 16:20:00 (EST-5)
Location: GOSHEN
Magnitude: 50.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A tree and wires on Williams Drive were downed by thunderstorm winds.

Thunderstorm Wind in HAMPSHIRE, MASSACHUSETTS
From 19-AUG-11 16:26:00 to 19-AUG-11 16:26:00 (EST-5)
Location: CHESTERFIELD
Magnitude: 50.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A tree and wires on Smith Road were downed by thunderstorm winds.

Hail in FRANKLIN, MASSACHUSETTS
From 19-AUG-11 16:30:00 to 19-AUG-11 16:30:00 (EST-5)
Location: SHELBURNE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Lightning in SUFFOLK, MASSACHUSETTS
From 19-AUG-11 14:30:00 to 19-AUG-11 14:30:00 (EST-5)
Location: (BOS)LOGAN INTL ARPT
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Newspaper

Lightning struck a K-9 police truck traveling along Perimeter Road at Logan International Airport.  The trooper was conscious and able to report the stricke but was taken to a local hospital to be evaluated.  The last report available indicated the trooper was not injured.  The trucks electrical systems were severely damaged.

Thunderstorm Wind in WORCESTER, MASSACHUSETTS
From 19-AUG-11 13:40:00 to 19-AUG-11 13:40:00 (EST-5)
Location: HOPEDALE
Magnitude: 50.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Large branches on Dutcher Street were downed by thunderstorm winds.

Hail in HAMPSHIRE, MASSACHUSETTS
From 19-AUG-11 15:40:00 to 19-AUG-11 15:40:00 (EST-5)
Location: WORTHINGTON CORNERS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in SUFFOLK, MASSACHUSETTS
From 19-AUG-11 14:21:00 to 19-AUG-11 14:21:00 (EST-5)
Location: BOSTON
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Large branches and wires on Pond, Hereford, and Tremont Streets.