The National Weather Service in Sterling Virginia has issued a * Severe Thunderstorm Warning for... South central Carroll County in north central Maryland... Northwestern Howard County in central Maryland... Northeastern Montgomery County in central Maryland... Southeastern Frederick County in north central Maryland... * Until 430 PM EDT. * At 347 PM EDT, a severe thunderstorm was located near Damascus, moving east at 25 mph. HAZARD...60 mph wind gusts and quarter size hail. SOURCE...Radar indicated. IMPACT...Damaging winds will cause some trees and large branches to fall. This could injure those outdoors, as well as damage homes and vehicles. Roadways may become blocked by downed trees. Localized power outages are possible. Unsecured light objects may become projectiles. * Locations impacted include... Columbia, Germantown, Damascus, Eldersburg, Mount Airy, Sykesville, Green Valley, Clarksburg, Monrovia, Laytonsville, Clarksville, West Friendship, Winfield, Lisbon, Glenwood, Dayton, Gaither, Watersville, Poplar Springs and Roxbury Mills. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building.