With a warm, somewhat humid air mass in place, a strong cold front moved through southern New England during the evening hours.  In addition, southern New England was on the southern edge of a strong jet stream aloft. The result was a quasi-linear convective system (QLCS) that moved through Massachusetts.  It caused significant damage in places, tearing the roof of buildings in Holyoke and hundreds of trees downed in parts of north-central and northeast Massachusetts.

Thunderstorm Wind in FRANKLIN, MASSACHUSETTS
From 15-MAY-20 18:40:00 to 15-MAY-20 18:40:00 (EST-5)
Location: EAST NORTHFIELD
Magnitude: 50.00 EG
Property damage: 4.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Multiple trees down in Northfield, closing a portion of Route 10.

Thunderstorm Wind in HAMPSHIRE, MASSACHUSETTS
From 15-MAY-20 18:49:00 to 15-MAY-20 18:49:00 (EST-5)
Location: NORWICH
Magnitude: 50.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Amateur Radio

In Huntington, a tree was reported down on Worthington Road.

Thunderstorm Wind in FRANKLIN, MASSACHUSETTS
From 15-MAY-20 18:49:00 to 15-MAY-20 18:49:00 (EST-5)
Location: GREENFIELD
Magnitude: 50.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Amateur Radio

A tree was reported down in Greenfield...no street given.

Thunderstorm Wind in HAMPDEN, MASSACHUSETTS
From 15-MAY-20 19:05:00 to 15-MAY-20 19:05:00 (EST-5)
Location: SMITH HIGHLANDS
Magnitude: 65.00 EG
Property damage: 140.00K
Crop damage: 0.00K
Reported by: Newspaper

Damaging winds peeled two roofs off of neighboring apartment buildings in Holyoke's Flats neighborhood, at the intersection of West Street and East Dwight Street.  A total of 140 residents ended up being displaced/homeless (47 families). Bricks from one of the buildings crashed onto West Street, damaging several cars.  Some wooden support beams also rained onto the streets below. Amazingly, no injuries were reported.  Damage figures approximate only.

Hail in WORCESTER, MASSACHUSETTS
From 15-MAY-20 18:59:00 to 15-MAY-20 18:59:00 (EST-5)
Location: ASHBURNHAM
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Dime size hail was reported in Ashburnham.

Thunderstorm Wind in FRANKLIN, MASSACHUSETTS
From 15-MAY-20 18:59:00 to 15-MAY-20 18:59:00 (EST-5)
Location: MONTAGUE
Magnitude: 50.00 EG
Property damage: 0.80K
Crop damage: 0.00K
Reported by: Amateur Radio

In Montague, a tree and wires were down on Center Street.

Thunderstorm Wind in WORCESTER, MASSACHUSETTS
From 15-MAY-20 18:58:00 to 15-MAY-20 18:58:00 (EST-5)
Location: WINCHENDON
Magnitude: 43.00 EG
Property damage: 0.80K
Crop damage: 0.00K
Reported by: Amateur Radio

In Winchendon, a tree and power lines were down near the intersection of Spring Street and Water Street.

Thunderstorm Wind in FRANKLIN, MASSACHUSETTS
From 15-MAY-20 19:09:00 to 15-MAY-20 19:09:00 (EST-5)
Location: WEST ORANGE
Magnitude: 51.00 EG
Property damage: 0.80K
Crop damage: 0.00K
Reported by: Amateur Radio

In Warwick, a tree and wires were down on Hockanum Road.

Thunderstorm Wind in FRANKLIN, MASSACHUSETTS
From 15-MAY-20 18:59:00 to 15-MAY-20 18:59:00 (EST-5)
Location: ORANGE ARPT
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

At 709 PM EST, a wind gust to 60 mph was recorded by the ASOS at Orange Airport (KORE).

Thunderstorm Wind in WORCESTER, MASSACHUSETTS
From 15-MAY-20 19:41:00 to 15-MAY-20 19:41:00 (EST-5)
Location: (ORH)WORCESTER MUNI
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The Worcester Airport (KORH) recorded a gust to 63 mph at 741 PM EST.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 15-MAY-20 19:15:00 to 15-MAY-20 19:15:00 (EST-5)
Location: TOWNSEND
Magnitude: 60.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Amateur Radio

In Townsend, a tree was down at the intersection of Old City Road and Fitchburg Road.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 15-MAY-20 19:25:00 to 15-MAY-20 19:25:00 (EST-5)
Location: HOVEY CORNER
Magnitude: 87.00 EG
Property damage: 250.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A microburst with estimated winds of 90-100 mph produced significant damage to trees and homes in a small part of Pepperell.  Several large trees were uprooted near Brookline Street and Cheyenne Road, some onto houses.  Trees were snapped about two to three feet from their bases farther down on Cheyenne Road near Algonquin Road.  A couple of trees were also downed on Gosselin Drive and Seminole Drive.  According to the Emergency Management Director, four telephone poles were snapped and seven homes had damage, six of which were significant with roofs penetrated and garages destroyed by falling trees.  Miraculously, there were no injuries.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 15-MAY-20 19:25:00 to 15-MAY-20 19:25:00 (EST-5)
Location: FORGE VLG
Magnitude: 78.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Another microburst, with discontinuous damage approximately 1.5 miles in length, occurred in Groton and Westford, from the same storm that produced a microburst in Pepperell.  A drone video showed extensive tree damage near Cow Pond Brook Conservation area in Groton,, with the vast majority of the trees blown down in a straight line.  A wind gust to 89 mph was measured at MIT's Millstone facility near the Groton/Westford line and the public reported a wind gust to 86 mph in their backyard in Westford.  Farther to the northeast, a tree was reported down on Forrest Road.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 15-MAY-20 19:35:00 to 15-MAY-20 19:35:00 (EST-5)
Location: CHELMSFORD CENTER
Magnitude: 50.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Amateur Radio

In Chelmsford, a tree was down on the southbound side of Route 3.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 15-MAY-20 19:30:00 to 15-MAY-20 19:30:00 (EST-5)
Location: FREDERICK CORNER
Magnitude: 50.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Amateur Radio

In Tyngsboro, trees were reported down on Scribner Road.

Thunderstorm Wind in WORCESTER, MASSACHUSETTS
From 15-MAY-20 19:35:00 to 15-MAY-20 19:35:00 (EST-5)
Location: SOUTH LANCASTER
Magnitude: 50.00 EG
Property damage: 4.00K
Crop damage: 0.00K
Reported by: Amateur Radio

In Lancaster, a tree was down on a house on Charlotte Street.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 15-MAY-20 19:40:00 to 15-MAY-20 19:40:00 (EST-5)
Location: DRACUT
Magnitude: 51.00 MG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trees were down at the University of Massachusetts at Lowell, where the Meteorology Department recorded a peak gust to 51 knots at 740 PM EST (840 PM EDT).

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 15-MAY-20 20:00:00 to 15-MAY-20 20:00:00 (EST-5)
Location: HUDSON
Magnitude: 50.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Trained Spotter

In Hudson, a tree was down on Stratton Road.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 15-MAY-20 20:07:00 to 15-MAY-20 20:07:00 (EST-5)
Location: SOUTH WILMINGTON
Magnitude: 50.00 EG
Property damage: 4.00K
Crop damage: 0.00K
Reported by: Trained Spotter

In Reading, a tree was down onto a garage on Summer Avenue.

Thunderstorm Wind in WORCESTER, MASSACHUSETTS
From 15-MAY-20 19:40:00 to 15-MAY-20 19:40:00 (EST-5)
Location: WORCESTER
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Multiple trees were down across the city of Worcester.  Law enforcement reported trees down on Maywood Street, Barnard Road, Revere Street, Perrot Street, Grafton Street, and Pioneer Road.

Thunderstorm Wind in MIDDLESEX, MASSACHUSETTS
From 15-MAY-20 20:13:00 to 15-MAY-20 20:13:00 (EST-5)
Location: CAMBRIDGE
Magnitude: 50.00 EG
Property damage: 7.50K
Crop damage: 0.00K
Reported by: Amateur Radio

In Cambridge, a power pole was down on Cambridge Street.

Thunderstorm Wind in SUFFOLK, MASSACHUSETTS
From 15-MAY-20 20:13:00 to 15-MAY-20 20:13:00 (EST-5)
Location: BRIGHTON
Magnitude: 50.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Public

In the Brighton section of Boston, a tree was down on Washington Street.

Thunderstorm Wind in SUFFOLK, MASSACHUSETTS
From 15-MAY-20 20:15:00 to 15-MAY-20 20:15:00 (EST-5)
Location: EAST BOSTON
Magnitude: 50.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Amateur Radio

In East Boston (street unspecified), a light pole was knocked down by thunderstorm winds.