The Hopkinton Fire Department tweeted a request at 10:40 a.m. for residents to take shelter for the following 20 minutes due to potentially severe weather approaching.
The National Weather Service issued a tornado watch for south central Middlesex County and surrounding areas. The weather could bring quarter-sized hail and 60 mph wind gusts.
Individuals are encouraged to move to an interior room on the lowest floor of their building until the threat passes.
UPDATE, 11 am.: The alert was changed to a thunderstorm warning until 11:15 a.m.
Wind damage to trees and power lines is possible, along with minor hail damage to vehicles.
A flash flood warning was issued until 1:45 p.m.