Feb. 22 (Bloomberg) -- An unexpected winter storm brought the heaviest snowfall of the season to New York City today, delaying area flights for hours and snarling road travel throughout the Northeast.

The city received as much as 8 inches (20 centimeters) of snow before it tapered off and changed to a mix of freezing rain and sleet around noon, the National Weather Service said. As little as 1 inch had been forecast. The agency canceled its winter storm warning, though it said freezing rain, possibly mixed with more snow, will make travel hazardous tonight.

``So far this has been a relatively easy winter, but we have a long day and a long night ahead of us,'' New York Mayor Michael Bloomberg said at a press conference.

The storm caused morning traffic accidents and delays in Connecticut, New Jersey, New York and Pennsylvania and created havoc for tractor-trailers throughout the New York City region, said Gene Michaels of Westwood One Inc.'s Metro Networks traffic service.

By around 1 p.m., major roads in the New York City region were plowed and ``down to the asphalt,'' Metro Networks said.

Staten Island had the biggest snowfall in New York City, with 8 inches on the ground as of 10:25 a.m., according to the weather service. Central Park received 6.

Fairfield County received the heaviest amount in Connecticut, with 9 inches in Stratford. Bergen County got the most in New Jersey, with 7 inches in Franklin Lakes.

`Stronger Than Expected'

``A coastal low-pressure system moved in overnight, bringing a lot of moisture,'' said Dave Sage, a meteorologist with the weather service in Buffalo, New York. ``It arrived a bit sooner and stronger than expected.''

As of noon, there were inbound flight delays of about an hour at John F. Kennedy International Airport in New York and Philadelphia International Airport, down from as much as seven, according to the Federal Aviation Administration's Web site.

New York's Long Island Rail Road, the nation's busiest commuter rail line, added eight eastbound trains for riders leaving work early. New Jersey Transit trains were delayed 20 minutes.

New York City Transit, the largest U.S. public- transportation network, said buses are running with system-wide delays and told customers to expect delays on the B and Q subway lines.

Freezing Rain

The weather service issued a winter storm warning until late today for Washington, D.C., as the storm front moved from the southwest. The area had received just a trace of snow and ice by noon, although parts of western Maryland received as much as 6 inches of snow.

``Our biggest concern is that this afternoon it turns to freezing rain,'' said Steve Chizmar, a spokesman for the Pennsylvania Transportation Department.

There is also a warning for southern New England through tomorrow morning. As much as 10 inches of snow may cover the Massachusetts Turnpike.

Consolidated Edison Inc., which provides electricity to homes and businesses in New York City and its Westchester County suburbs, had as many as 500 Manhattan customers without power, according to its Web site. About 1,600 Staten Island customers lost electricity earlier.

Public Service Enterprise Group Inc.'s PSEG utility in New Jersey reported about 200 customers were without power.

Delta Air Lines Inc., JetBlue Airways Corp. and US Airways Group Inc. all waived rebooking fees for travelers wanting to change their flights for today.

Michael Bloomberg is the founder and majority owner of Bloomberg LP, the parent company of Bloomberg News.

To contact the reporters on this story: Demian McLean in Washington at dmclean8@bloomberg.net; Chris Dolmetsch in New York at dolmetsch@bloomberg.net.

Last Updated: February 22, 2008 15:38 EST