A reported tornado near Lanham yesterday afternoon popped windows out of automobiles, uprooted trees and smashed them into houses and overturned a large trash receptacle, Prince George's County fire officials reported.

The suspected tornado apparently was spawned by a violent thunderstorm that passed through the Washington area yesterday, dumping as much as 2 inches of rain in 30 minutes. In an unrelated incident, a Rixeyville, Va., man was killed when he was struck by lightning.

Damage from the reported tornado was confined to a 10- to 12-block area near Whitfield Chapel and Annapolis roads, fire officials said. No injuries were reported.

A witness told fire officials he saw a funnel cloud touch down about 5:30 p.m. National Weather Service forecaster Harold Hess said last night that investigators will study the damage today to see if it was caused by a tornado.

"We have one reliable witness, a pilot who has seen them tornadoes in the Midwest, who says he thinks this was a tornado," Hess said.

"He said he saw a funnel cloud and he took refuge inside a building, and as soon as he got inside the building the roof started to blow off."

Officials said the roofs of a car repair shop at 9540 Smith St. and a private home at 6320 Main St., Lanham, were partially blown off and pieces scattered on top of cars parked nearby. They said a large trash dumpster was turned upside down and a 30-foot boat on a trailer apparently was picked up and moved. No damage estimates were available.

Hess said that because of yesterday's moisture, and conditions of hot air near the ground and cold air aloft, a tornado could have been formed when a weak front moved into the area from the northwest about 4 p.m.

The storm, which moved through the area at about 30 mph, slowed evening rush hour traffic to a crawl, flooding roadways and stalling car engines. Rain was heaviest in the District of Columbia and Maryland, particularly Montgomery and Prince George's counties.

The strongest winds associated with yesterday's thunderstorm were recorded by weather observers at 30 mph, "but obviously they the winds were much stronger" in Lanham, Hess said.

"Because of the damage they are talking about, it's almost a matter of semantics whether it was a tornado or not."

He said the Lanham cloud followed the pattern of tornadoes that have struck this area, touching down briefly and traveling only a short distance.

About 5,200 Potomac Electic Power Co. customers in Montgomery and Prince George's County lost electrical service during the height of the storm, but a company spokeswoman said service to most had been retored by late last night.

Although the storm was less severe in Northern Virginia, a 24-year-old painter was killed in Rixeyville, Va., near Culpeper, and another man was severely burned when they were struck by lightning while cleaning paintbrushes under a tree, Rixeyville police said.

They said Richard Lee West and Kevin Paul Kelly, 33, had recently completed a painting job at a Holiday Inn and were cleaning their brushes with gasoline when a bolt of lightning struck about 3:30 p.m., killing West instantly.

Kelly was taken to the Unversity of Virginia Hospital and was reported in critical condition.