For your protection move to an interior room on the lowest floor of a building. Frequent cloud to ground lightning is occurring with this storm. Move indoors immediately. Lightning is one of nature's leading killers. Remember, if you can hear thunder, you are close enough to be struck by lightning. Torrential rainfall is occurring with this storm, and may lead to flash flooding. Do not drive your vehicle through flooded roadways.

SVRBOX The National Weather Service in Boston/Norton has issued a * Severe Thunderstorm Warning for... Northeastern Worcester County in central Massachusetts... Northwestern Middlesex County in northeastern Massachusetts... * Until 700 PM EDT. * At 600 PM EDT, a severe thunderstorm was located over Shirley, or 8 miles northeast of Leominster, moving south at 10 mph. HAZARD...60 mph wind gusts and penny size hail. SOURCE...Radar indicated. IMPACT...Expect damage to trees and power lines. * Locations impacted include... Leominster, Fitchburg, Westford, Acton, Pepperell, Groton, Lunenburg, Townsend, Littleton, Lancaster, Sterling, Ayer, Shirley, Stow, Harvard, Boxborough, Bolton, Dunstable, and Ashby.