American Airlines
American Airlines canceled over 300 flights Jan. 4 due to Winter Storm Grayson. In this photo, a worker prepares luggage for American Airlines flights at O'Hare International Airport in Chicago, Nov. 30, 2017. Getty Images

A number of airlines have already canceled and are still proactively canceling hundreds of flights Thursday and offering travel waivers as a powerful winter storm climbs up the East Coast. Winter Storm Grayson is expected to batter the Northeast, leading to widespread disruption of flights throughout the day.

The storm is expected to lash the region with high winds, snow and consecutively record low temperatures. Tracking service FlightAware.com said Wednesday that over 1,700 flights scheduled for Thursday were canceled.

Most cancellations were concentrated at airports in the Northeast — like Boston Logan International Airport, where more than half the flights scheduled for Thursday have been scrubbed. Nearly half the flights at New York's LaGuardia Airport also stood canceled. Two other New York-area airports, John F. Kennedy and Newark, were also hit hard by the cancellations along with other smaller airports in the Northeast.

American Airlines said in a press release Wednesday evening that along with their regional partners, it had canceled over 300 flights Jan. 3 and 630 flights on Jan. 4 due to the storm.

American Airlines spokesman Ross Feinstein said the Fort Worth-based carrier would be moving its aircraft out of Boston Logan Airport on Wednesday night ahead of the storm, with all Thursday departures at the airport already canceled. He added that depending on how the storm progressed, inbound flights could begin late Thursday with more service restarting Friday. The airline also canceled all flights of its regional carriers and the air shuttle operations at LaGuardia Airport for Thursday, Feinstein said.

“We’re looking proactively so our customers aren’t in mid-journey when their flight could potentially be canceled,” Feinstein added, according to Dallas News.

Feinstein added that American Airlines was not expecting the same scale of disruption to its operations in Washington or Philadelphia, but warned of scattered cancellations due to weather conditions in those areas Thursday.

The airline is also offering waivers to passengers scheduled to travel between Wednesday and Friday. The waivers are divided into two, on the basis of geography: Northeast and Southeast. In the Northeast (from Maine to New Jersey), the airline will waive normal change fee on flights booked for Jan. 4 and 5 (Thursday and Friday), as long as passengers make alternate bookings for travel between now and Jan. 8. In the Southeast, passengers heading to and from airports like Charleston's CHS and Tallahassee's TLH on Jan. 3 and 4 will have their normal change fees waived for travel before Jan. 7.

In order to incur no fees, flyers must rebook in the same class of service as they had booked earlier on their original ticket, and the new flight must depart by Jan. 7 or Jan. 8, depending on the itinerary. Travelers flying within the United States and Canada can rebook their flights online or call American Airlines’ customer service at 800-433-7300 to make the changes.

A full list of airports that are included in the waiver program are listed on American's travel alert website. The airline also issued a travel advisory that can be read here.

Grayson, also being called the "bomb cyclone," is expected to dump at least half a foot of snow in the New York City region and 8 inches to a foot of snow on the Boston area Thursday, according to CBS and ABC-affiliate KNOE-TV.

The National Weather Service also predicted Wednesday that the storm could undergo something called “bombogenesis.” That means the storm could quickly escalate over a period of 24 hours.