(Update's with mayor's comments, latest cancellation figures)
By Ellen Wulfhorst
NEW YORK, Feb 3 (Reuters) - A fast-moving winter storm swept into the U.S. Northeast on Monday, yet again forcing flight cancellations, slowing traffic and proving weather-forecasting groundhog Punxsutawney Phil right.
Travelers leaving the New York City area after Sunday night's Super Bowl championship football game faced long delays at the region's airports and risky driving on snow-covered roads.
Hardest hit by the storm-related flight delays and cancellations was Newark Liberty International Airport in New Jersey, the closest to the stadium where the Denver Broncos fell to the Seattle Seahawks 43-8 in the National Football League's matchup.
"Only thing worse than sitting through awful game last night is now sitting at airport on weather delay, probable cancellation," tweeted Nick Griffith, sports director at TV station Fox 31 in Denver, adding the hashtag "#longtrip."
The storm was expected to drop 4 to 8 inches (10 to 20 cm) of snow on an area stretching from eastern Kentucky to eastern New York state, the National Weather Service said.
"Snow is coming down faster than we can plow it," New York Mayor Bill de Blasio said at a news conference.
He said efforts to plow city streets were aimed at an improved performance over the cleanup of a big storm in late January.
In that storm, some residents of Manhattan's tony Upper East Side neighborhood claimed their streets were ignored as part of the mayor's key campaign theme of addressing income inequality.
"The response to the last storm obviously left something to be desired," de Blasio said at the news conference.
He said New York City has adjusted how it responds to storms by coordinating agency efforts, changing snow removal routes and scouting conditions in various neighborhoods.
"It's good we got the Super Bowl done so well" before the storm hit, added de Blasio, whose city shared in the Super Bowl hosting honors with New Jersey.
At Newark Airport across the Hudson River in New Jersey, 204 flights were canceled as of midafternoon on Monday, according to Flightaware.com, an online site that tracks air traffic.
Plenty of football fans were stewing after getting stuck for hours on Sunday trying to board trains to and from the game at the New Jersey Transit hub station of Secaucus Junction.
"So, folks spent $1500+ for the honor of 3 hours to get in their seats, 6 hours to leave, & now 3 hour snow delay at the airport," noted one observer on Twitter.
Declaring it the first-ever "Transit Bowl," New Jersey Transit tweeted that it transported more than 33,000 fans, which it said was four times as many people as the National Football League had predicted.
Thanks to the wet snowstorm, delays and cancellations also plagued New York's LaGuardia Airport and John F. Kennedy International Airport, as well as Philadelphia International Airport.
The small Teterboro Airport near the football stadium in New Jersey, which handles the private jets that would whisk away celebrities and other moneyed Super Bowl attendees, also reported delays, Flightaware.com said.
"All the people came here for the Super Bowl thinking "Jersey ain't bad" are probably now stuck in the airport for the rest of the day," tweeted Jonathan Chung.
Across the United States, 1,669 flights were canceled, Flightaware.com said.
Driving was hazardous along the Interstate 95 corridor from Washington north to Boston, according to meteorologists.
The storm blew in after dumping several inches of snow in the Ohio Valley on Sunday, the day famed groundhog Punxsutawney Phil emerged from his burrow in the town of Punxsutawney, Pennsylvania, saw his shadow and - as the legend goes - predicted six more weeks of winter.
Still more wintry weather lay ahead, the New York mayor said.
"The fact is that we are facing not one, not two, but three storms potentially this week," he said.
A second storm was likely to arrive in the region on Tuesday night and a third on the weekend, he said.
The National Weather Service on Monday issued winter storm warnings for sections of Colorado, Kansas, Missouri, Ohio, Kentucky, Pennsylvania and Maryland, as well as New Jersey, Delaware and New York City and its surrounding areas. (Reporting by Ellen Wulfhorst; Editing by Peter Galloway and Jonathan Oatis)