A winter storm moving up the US and Canadian east coast is the driving force behind more than 4,600 US flight cancellations—and counting—since Jan. 3.

As of Jan. 4 at 3 p.m. EST, nearly 4,000 flights have been canceled in the US, with United Airlines, American Airlines, JetBlue Airways, Delta Air Lines, Southwest Airlines and regional carriers Republic Airline, ExpressJet Airlines and Delta subsidiary Endeavor Air all reporting hundreds of cancellations, according to flight tracking site Flight Aware.

Chicago-based United and Dallas/Fort Worth-based American have reported at least 1,105 cancellations between them, followed by New York-based JetBlue with 411, Atlanta-based Delta with 396, Dallas-based Southwest with 352 and Republic with 312 (Republic operates regional routes for American Airlines, Delta and United).

New York metropolitan area airports are taking the brunt of the storm cancellations, with 1,005 flights canceled at Newark Liberty International Airport (EWR) as of 3 p.m., plus 695 canceled at LaGuardia (LGA) and 592 at New York JFK.

Boston’s Logan International Airport (BOS) is also being hard hit, with 733 cancellations. Significant cancellation numbers are also being seen at Philadelphia International Airport (340); Chicago O’Hare (223); and Hartsfield-Jackson Atlanta International Airport (204).

By comparison, on a comparatively average winter day (Tuesday Jan. 2), Flight Aware reported 278 total cancellations on flights within, into, or out of the US.

The storm is forecast to move northward into Nova Scotia overnight into Jan. 5, but a large Arctic air mass will subsequently settle over the US east coast, plunging the region to near-zero temperatures through Jan. 6.

Mark Nensel mark.nensel@informa.com