Sudden thunderstorms accompanied by heavy rains, brilliant displays of lightning and gusty winds swept through the Washington area last night, flooding some roadways and leaving approximately 16,000 homes without power.

Winds of more than 40 mph were reported in some areas of suburban Maryland, and at least two automobiles were crushed by toppled trees in the District. A few houses were struck by lightning, but authorities reported no injuries and no extensive damage.

Potomac Electric Power Co. reported that about 14,000 customers were without electricity, mostly in southern Montgomery County and the District, as tree limbs fell on power lines and rain and lightning blew fuses. Company spokeswoman Nancy Moses said crews would be working through the night to restore power in those areas.

In Northern Virginia, about 2,100 Arlington homes went dark shortly after 11 p.m. when lightning apparently struck power lines. Officials at Virginia Power expected to restore electricity early this morning.

The U.S. Park Police said the heavy rains left up to six inches of water on portions of the George Washington Memorial Parkway near I-395, as well as on stretches of the Rock Creek Parkway in the city and on 15th Street near the Washington Monument grounds.

According to the National Weather Service, the storms developed in Montgomery and Loudoun counties as the area became trapped between a cold air mass to the north and competing hot air moving in from the south. The storms intensified and developed heavy winds as they moved east over the city and into southern Prince George's.

Meteorologist Joseph Czarniecki said that scattered thunderstorms could occur today. Temperatures are expected to climb into the 90s, he said, accompanied by a sharp increase in humidity.

"It's going to be hot and humid," Czarniecki said. "You'll really feel it by Sunday."