EF3 tornado in Worcester County, Massachusetts

A supercell thunderstorm developed over western Massachusetts. This storm strengthened and produced a long-lived, very significant tornado that did extensive damage across southwest and south central Massachusetts.

This storm will be noted not only for its intensity, but also for the length of the continuous damage path, approximately 38 miles, the last 6 of which were in Worcester County. The tornado was also very wide at some points, reaching a maximum width of one half mile.

Once the tornado moved into the Brimfield State Forest, significant damage occurred to both structures and forested areas for several miles before the tornado reached the Southbridge Municipal Airport. Here numerous aircraft were lifted off the ground and into the woods east of the airport. The tornado continued east before lifting in the southwest part of Charlton.

The majority of the damage done by this tornado was done during the first 31 miles of the track, in Hampden County. All of the property damage, injuries, and fatalities are accounted for in the Hampden County portion of the tornado. The majority of the property damage and injuries, and all of the fatalities occurred in Hampden County. However, there was enough damage in Sturbridge and Southbridge that President Obama amended his original disaster declaration for Hampden County to include Sturbridge and Southbridge.

An upper level closed low over southern Ontario tracked across Quebec while at the surface, a cold front over western New York crossed southern New England in the evening of June 1. An environment characterized by high CAPE (2000-3000 J/kg) and high shear (greater than 200 m2/s2) was in place across western Massachusetts. In addition, mid level lapse rates were an impressive 7 to 8 C/km. Thunderstorms forming ahead of the front organized into discrete supercells in an environment highly favorable for tornado formation.

While convection fired early in the day along a weak low level theta-e ridge across north central Massachusetts and southern New Hampshire, clearing allowed for rapid destabilization in the afternoon.

Thunderstorms developed during the morning ahead of the cold front from eastern Pennsylvania into southeast New York and Vermont. By about 3 pm, the storms entered western Massachusetts and were in the form of discrete supercells. By 4 pm, several supercells had developed across southern Vermont, southwest New Hampshire, and western Massachusetts. At that time, the supercell which eventually produced the most significant tornado entered Hampden County from the Berkshires. This cell produced what was evaluated to be an EF-3 tornado touching down in Westfield and continuing on a 38 mile long trek through West Springfield, Springfield, Wilbraham, Monson, Brimfield, and Sturbridge. This tornado was on the ground for an estimated 70 minutes.

About two hours later, another supercell tracked just to the north of the storm track of the EF3 tornado. While its rotation was not as strong, it produced brief tornadoes in Wilbraham (EF1), North Brimfield (EF1), and Sturbridge (EF0).

While the focus was certainly on the tornadoes and their damage, damaging winds, large hail up to two inches in diameter, and some flash flooding also occurred across southern New England.