Over 1,500 flights in US canceled, as thunderstorms slam Northeast

Over 2,600 flights have been canceled and close to 7,900 have been delayed across the United States Sunday, according to data from FlightAware.

Airports across the Northeast are seeing the majority of the disruptions, as thunderstorms hit the region throughout the day, according to the Federal Aviation Administration.

New Jersey's Newark Liberty International Airport is experiencing the most significant cancellations, with 362 flights being canceled and 337 flights experiencing delays, according to FlightAware.

John F. Kennedy International Airport has seen 318 canceled flights and 426 delayed flights. Additionally, 270 flights have been canceled at LaGuardia Airport with 292 delayed, and 259 flights canceled and 459 delayed at Boston Logan International Airport, FlightAware data shows.

JetBlue is seeing a significant impact, with 27% (283) of flights canceled and 43% (445) delayed. The regional airline Republic Airways is also seeing an impact with 32% (320) of flights canceled and 20% (201) delayed, according to FlightAware.

Regional airline Endeavor Air, a Delta subsidiary, is seeing 26% (174) of flights canceled and 18% (122) flights delayed.

"Slow-moving thunderstorms will cause delays this AM into early PM in the Northeast, Midwest & Southeast," the FAA said on Twitter on Sunday.

In the Northeast, over 56 million people were under a flood watch, as heavy rain moved through on Sunday morning, causing flash flooding in parts of Virginia, Pennsylvania and New Jersey.

ABC News' Julia Jacobo contributed to this report.