* Thousands of flights canceled ahead of storm
* High winds, up to two feet of snow forecast (Adds additional flights canceled, schools closed, state of emergency in Virginia)
By Daniel Trotta and Scott Malone
NEW YORK/BOSTON, March 13 (Reuters) - A fast-moving winter storm bringing up to two feet of snow was expected to hit the northeastern United States, forecasters warned on Monday, prompting airlines to cancel thousands of flights and some mayors to order schools to close on Tuesday.
The National Weather Service issued blizzard warnings for parts of Pennsylvania, New Jersey, New York and Connecticut, with forecasts calling for up to 2 feet (60 cm) of snow by early Wednesday, with temperatures 15 to 30 degrees below normal for this time of year.
Some 50 million people along the Eastern Seaboard were under storm or blizzard warnings and watches.
"When this thing hits, it's going to hit hard and it's going to put a ton of snow on the ground in a hurry," Massachusetts Governor Charlie Baker told reporters on Monday. He urged people to consider working from home if they could.
"It's going to snow hard and fast for a long period of time. It will create whiteout conditions," Baker said.
Airlines preemptively canceled more than 4,000 flights ahead of the storm, according to tracking service FlightAware.com. The airports with the most cancellations were Newark International Airport in New Jersey and Boston Logan International Airport.
American Airlines canceled all flights into New York's three metropolitan area airports, Newark, LaGuardia Airport and John F. Kennedy International Airport, and JetBlue Airways reported extensive cancellations.
Delta Air Lines canceled 800 flights for Tuesday for New York, Boston and other northeast airports, and United Airlines said it would have no operations at Newark or LaGuardia.
"We’re keeping a close eye on things and depending on how things go, will plan to ramp back up Wednesday morning," United said in a statement.
New York Governor Andrew Cuomo declared a state of emergency, and New York City, Boston and Providence, Rhode Island, canceled public school sessions for Tuesday in anticipation of the storm.
German Chancellor Angela Merkel, who was due to meet President Donald Trump in Washington on Tuesday, postponed her trip until Friday, the White House said.
The storm comes near the end of an unusually mild winter along much of the East Coast, with below-normal snowfalls in cities such as New York City and Washington, D.C.
Boston was braced for up to a foot (30 cm) of snow, which forecasters warned would fall quickly during the storm's expected peak on Tuesday, making travel dangerous.
"During its height we could see snowfall rates of 1 to 3 inches (2.5-7.6 cm), even up to 4 inches (10 cm) per hour," said Alan Dunham, a meteorologist with the National Weather Service in Taunton, Massachusetts.
Winds were forecast to gust up to 60 mph (100 kph) in places, with the potential to cause power outages and coastal flooding.
The Port Authority of New York and New Jersey readied hundreds of pieces of snow equipment at the three major New York area airports. Thousands of tons of salt and sand were prepared for airport roads, parking lots, bridges and tunnels.
The United Nations headquarters said it would close on Tuesday, but the New York Stock Exchange vowed to remain open for the tiny fraction of trades that still take place on the trading room floor on Wall Street.
The storm's wrath was expected to be felt as far south as Virginia, where Governor Terry McAuliffe declared a state of emergency ahead of its arrival.
Washington, which often bogs down with even low levels of snow, was expecting 5 inches (13 cm) and twice that in outlying areas. (Additional reporting by Laila Kearney, Peter Szekely, Michelle Nichols and Alana Wise in New York, Nate Raymond in Boston and Timothy Mclaughlin in Chicago; Writing by Scott Malone and Dan Whitcomb; Editing by Toni Reinhold and Cynthia Osterman)