More than 2,600 flights were cancelled and nearly 8,000 delayed across the United States on Sunday due to thunderstorms, according to ABC News. Majority of these cancellations and delays were reported from the Northeast region, according to Federal Aviation Administration (FAA). Here, 1320 flights were cancelled with more than 350 alone from New Jersey's Newark Liberty International Airport, said NBC News. Severe weather also prompted ground stops at John F Kennedy airport and La Guardian airports, the outlet further reported.
Airlines posted advisories on Twitter, urging passengers to check flight timing and weather condition before heading to the airport.
FlightAware data showed that 318 flights were cancelled at 426 delayed at JFK, 270 cancelled and 292 delayed at La Guardia and 259 flights cancelled and 459 delayed at Boston Logan International Airport.
The northeastern United States has been witnessing heavy rain and flooding across several states. Parts of New York, New Jersey, Connecticut, Pennsylvania, Massachusetts and Vermont are under flood warnings, with states in the region recording rapid rainfall and "life threatening" flash floods, according to the National Weather Service (NWS).
The NWS also issued a tornado watch for parts of Connecticut, Maine, Massachusetts, New Hampshire, New York and Rhode Island on Sunday morning.
Meanwhile, parts of western and southern US were under heat warnings or advisories on Sunday due to relentless, record-breaking temperatures.
The NWS warned of "a widespread and oppressive heat wave" in parts of the Southwest, western Gulf Coast and southern Florida, with sizzling temperatures carrying into the coming week raising health risks for millions.
By Sunday afternoon, California's famous Death Valley, one of the hottest places on Earth, had reached the near-record temperature of 126 degrees Fahrenheit (52 degrees Celsius).
Heatwaves are occurring more often and more intensely in major US cities, according to the federal Environmental Protection Agency, with a frequency of six per year during the 2010s and 2020s compared to two per year during the 1960s.
