The twister touched down in Worcester around 8:10 p.m., ending around four minutes later. It felled trees and power lines, damaging cars, but no one was hurt. The NWS office in Taunton measured it an EF-0, the lowest rating on the tornado scale, with winds around 85 miles per hour.
About ten minutes later, residents reported getting a tornado warning from the NWS.
Michael Roescher, a storm-watcher and Worcester resident who lost his home to a tornado in 2011, expressed frustration that he was again caught off guard.
"My hopes are that with watching these things, sometime down the road we can improve notification locally," he said. "Not giving the warning four minutes past."
Sunday's storm was the second in the region this summer. On July 28, an EF-2 twister hit the Boston suburb of Revere, with the NWS warning again coming after the storm passed.
But while prior warning would obviously be preferable WCVB meteorologist Mike Wankum explains that it's often difficult for radar to predict smaller storms like the two that struck Massachusetts this summer.
"As the thunderstorm spins up it's often difficult to determine if it will produce a tornado," he said. "Doppler radar signatures may be weak or difficult to interpret."
"Once damage reports arrive, meteorologists know a specific radar signature is capable of producing a tornado. If that radar signature continues, a warning is issued. In both Worcester and Revere, residents were fortunate no further touchdowns were reported downstream as the cells moved east."
In other words, a late warning is actually a good thing: It means the likelihood of a severe storm causing significant damage is much smaller.