People walk in a park along the Hudson River across from New York on Tuesday. (Gary Hershorn/Reuters)

A winter storm that could drop seven inches of snow on the Washington area (and possibly up to 14 inches on New York City) moved into the Northeast on Tuesday, wreaking havoc on air travel and canceling thousands of flights.

More than 3,000 flights had been canceled as of 7:30 p.m., according to FlightAware, with another 2,600 flights delayed. The cancellations were concentrated in the Northeast, with more than 1,400 flights through the New York area’s three airports (LaGuardia, John F. Kennedy International and Newark Liberty International) halted.

More than 800 flights through the Washington area’s airports (Reagan National, Dulles International and Baltimore-Washington International) had also been halted. There were also more than 500 flights nixed at Philadelphia International Airport, and more than 230 flights scrapped at Boston’s Logan International Airport.

Travelers should be ready for these cancellations and delays to keep mounting. And headaches at these key hubs could have a ripple effect on flights nationwide, snarling travel across the air traffic system.

Airlines have begun waiving fees for travelers impacted by the storm, with USAirways, Delta and JetBlue among those allowing passengers to change tickets without paying an added charge.

The problems on Tuesday come just weeks after travelers encountered days of cancellations, delays and travel anguish that stemmed from a brutal cold and snow in the Midwest and Northeast.

For those looking to travel in the Northeast, Amtrak said that it planned to run a normal schedule in the region, though it warned that the weather could create some delays.

The rail agency had reduced service between Washington and Boston during the winter storm that shrouded much of the Northeast in snow and brutal cold earlier this month, running fewer Acela and Northeast Regional trains along that stretch.

This post has been updated to include the latest flight cancellation numbers. Last update: 7:45 p.m.