A severe thunderstorm bringing hail the size of golf balls and wind gusts up to 45 miles an hour left about 17,000 homes without electricity in Northern Virginia yesterday and caused scattered power outages in suburban Maryland and the District of Columbia.

The storm swept into the area around 4:30 p.m., pushed by a cold front approaching from the north and accentuated by 93-degree temperatures, the highest recorded since April.

Hardest hit by the winds and hail were Fairfax, Loudoun and Arlington counties. Virginia Power crews were still working last night to restore electricity to about 5,000 customers. Most of the outages there were caused by trees and limbs toppled over power lines, a company spokesman said.

A spokeswoman for the Potomac Electric Power Co. said about 500 scattered households were cut off in Maryland and the District, but that power to most was restored within a few hours.

National Weather Service forecaster Harold Hess said that the cold front that moved through the area last night will bring generally cooler temperatures in the 80s today and tomorrow, as well as a significant drop in humidity.

"It will seem like quite pleasant weather to most people," Hess said.