From The National Weather Service
Several factors are coming together for more severe thunderstorms mid afternoon into early evening. The main concern is for straight line wind damage and large hail. Very heavy downpours could also cause local urban and poor drainage flooding. We could see one or more short lines of storms form and move through.
Frequent lightning will also accompany many of these storms.
The risk for severe weather encompasses all of central and southern New England. The time frame of greatest risk appears to be between 3 pm and 8 pm, but there could be isolated severe thunderstorms between now and 3 pm.