Thunderstorms and heavy rain swept the Washington area yesterday afternoon as the first cold front in more than a month pushed the record-breaking hot, muggy air of recent days out to sea.

The National Weather Service said the front passed through the area about 4 p.m. bringing with it drier air and more comfortable temperatures.

Temperatures in the 70s and some showers continued late into the night with forecasters predicting mild weather and rain for today.

There were scattered reports of downed power lines in Springfield, Warrenton and Alexandria caused by high winds. But, the abrupt change in climate came as a welcome relief to many area residents who sweltered through 97-degree heat on Friday.

Weather Service meteorologist Cliff Crowley said it has been a surprising summer here, first because balmy, spring-like weather lasted until mid-July without a single 90-degree day. Then, he said, a continuous "Bermuda high" - an air mass that originates offshore - moved into the area and stayed for more than a month.

As the heavy rains hit yesterday, motorcyclists and bicyclists were driven to the shelter of underpasses, and sightseers on the Mall dashed for the relative protection afforded by shade trees.

In Alexandria, Paul Jones of 2645 N. Van Dorn St. parked his car beneath some trees and went into his apartment, only to discover, when he looked out his apartment window, that a tree was falling straight toward his building.

The tree narrowly missed the car, but hit the building, Jones said.

"You have to crawl underneath it to get out of the courtyard." Power in the apartments was knocked out, Jones said.

In Maryland and the District, about 700 customers were without electricity for short periods, a Pepco spokesman said. The main areas hit by power outages were in the Oak Grove, Bell's Mill and Middlebrook areas of Prince George's County and in Northern Washington.

In most instances, power was restored with a few hours.

The 97-degree temperature registered in the area on Friday was the hottest of the year and the highest ever recorded for that date at Dulles International Airport.

In Washington yesterday, the threat of rain didn't deter some 700 swimmers splashing through the Recreation Department's Francis Pool at 25th and N Streets NW.

Ice cream vendor Steven Straughter welcomed the rain. He moseyed around Cupont Circle with his pushcart shortly before the clouds burst, saying he would take cover just until the showers had past.

"I make $10 after an evening shower," Straughter said. "It's cool, and people like to eat ice cream after the rain."