Travellers carry their luggage through a snow bank on 7th Avenue in front of Penn Station after a snow storm in New York December 27, 2010.
The National Weather Service in Upton has issued a winter storm warning for heavy snow and sleet for portions of northeast New Jersey, New York City and Long Island. REUTERS

New York is once again hit by heavy snowfall and stormy weather as the city declared a weather emergency from Tuesday evening through Wednesday afternoon in many parts of the region. According to the US National Weather Service, the wintry and stormy weather condition is going to persist for some time in New York because of the two low pressure systems, one moving up the eastern US seaboard and another from the Ohio and Tennessee valleys, which are set to merge off the mid-Atlantic coast and intensify the condition.

Cancellation of flights, delays, stranded travelers, in-city commuting havoc and the like are likely to persist in the coming days. The storm is expected to dump as much as 12 inches of snow on New York City through Wednesday. As the City braces for season's third winter storm in less than three weeks, here are some key facts on flight cancellations and travel conditions.

Airlines and number of flights canceled for Wednesday:

• Delta Air Lines – 800
• American Airlines – 500
• US Airways – 1,340
• AirTran Airways – 50

Airports closed due to the storm:

• According to Federal Aviation Administration (FAA), due to storm, the Long Island Mac Arthur Airport (ISP) was closed as of Jan 12 at 03:55 AM EST. The date/time when the airport is expected to reopen is Jan. 12 at 10:00 AM EST.
• The MMU airport was closed as of Jan. 12 at 04:50 UTC. The date/time when the airport is expected to reopen is not known.
• Boston Logan International Airport said in a Facebook message that the average delays to JFK Airport are 168 minutes, 86 minutes to EWR and 60 minutes to LGA.