The National Weather Service in Sterling Virginia has issued a * Severe Thunderstorm Warning for... Northwestern Howard County in central Maryland... Montgomery County in central Maryland... Southern Frederick County in north central Maryland... Central Loudoun County in northern Virginia... North central Fairfax County in northern Virginia... * Until 745 PM EDT. * At 705 PM EDT, severe thunderstorms were located along a line extending from Ballenger Creek to Point Of Rocks to 6 miles north of Leesburg to near Round Hill, moving east at 35 mph. HAZARD...60 mph wind gusts. 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... Germantown, Frederick, Rockville, Gaithersburg, Reston, Leesburg, Olney, Damascus, Broadlands, Lansdowne, Lowes Island, Poolesville, Harry Grove Stadium, Aspen Hill, Potomac, Ashburn, Montgomery Village, Sterling, North Potomac and Ballenger Creek. PRECAUTIONARY/PREPAREDNESS ACTIONS... Remain alert for a possible tornado! Tornadoes can develop quickly from severe thunderstorms. If you spot a tornado go at once into the basement or small central room in a sturdy structure. For your protection move to an interior room on the lowest floor of a building. By The National Weather Service, Sterling, Va.