Flights at numerous major airports, from New York to Washington DC, were halted on Monday, resulting in significant disruptions for thousands of travelers along the East Coast.

The Federal Aviation Administration first declared a ground stop at John F Kennedy International Airport on Monday afternoon because of intense thunderstorms in the vicinity.

This ground stop also affected Philadelphia International Airport and Ronald Reagan Washington National Airport, with the advisory swiftly extending to other prominent airports along the East Coast.

The ground stops were only expected to last into the early evening, however, the resulting domino effect in departure traffic has already sent wait times spiraling out of control, with some airports reporting waits of more than two hours to take off.

Including the flights delayed by the storms, there have already been over 1,500 flights delayed in the New York, Philadelphia, and Washington areas Monday.

Overall, the final day of June was a miserable day for air travel, with more than 5,700 flights into and out of the US delayed, disrupting hundreds of thousands of travelers.

The latest update from the FAA said that departure delays at JFK were now at two hours and 35 minutes and increasing as the storm moves in.

Flights in Washington were grounded until 5pm and the flights in Philadelphia were stuck until 6:30pm.

In Philadelphia, the news got a little better as the ground stop dragged on, with delays dropping to 75 minutes, according to the latest data from the FAA.

A ground delay has also been issued for New York’s LaGuardia Airport due to the impending weather along the East Coast.

That weather alert is in effect until 11:59pm ET on Monday and has led to average delays of 157 minutes – a staggering two hours and 37 minutes.

The situation at JFK was later updated to a ground delay which is also in effect until midnight Monday.

JFK is the New York area’s busiest airport, with roughly 60 million travelers using the airport each year.

New Jersey’s Newark Liberty Airport was later added to the weather alert, shutting down outgoing flights until 6:30pm ET. 

At Newark, the ground stop threatens to make a bad travel situation even worse, as the airport has been plagued with delays due to recent air traffic control blackouts and ongoing construction.

Monday’s ground delay at Newark has pushed the average delays in New Jersey to an agonizing three hours and 17 minutes.

Flights at George Bush Intercontinental Airport in Houston were grounded until 6pm ET, but a reason was not given by the FAA Monday.

Local news outlets noted that the ground stop was also due to poor weather in the Texas area.

Over 800 flights throughout the US were cancelled on Monday.

As the ongoing delays slowly turn into cancellations, travel experts say it’s best to be prepared for the worst and have a plan for rebooking your flight.

Dollar Flight Club founder Jesse Neugarten told Travel + Leisure: ‘If the plane that’s supposed to become your flight is delayed in another city, you’ll often see the writing on the wall before the airline officially tells you.’

Neugarten added that, when it comes to rebooking a cancelled flight, you have to act quickly.

The travel expert recommended using your airline’s app or website to view rebooking options before you even get out of line at the gate.

‘Airlines usually load alternate flight options right into the app when a cancellation happens, and sometimes you’ll even get rebooking offers without asking,’ Neugarten explained.

Also, if you’re trying to call the airline’s customer service line to rebook, try the help desk line for another country like Canada or the UK.

Neugarten noted that the wait times on the phone are usually much shorter than the US help line but the operators can still provide help rebooking a cancelled flight.

Travelers on Tuesday may have to pack some patience as well. Meteorologists from AccuWeather said that there will be more thunderstorms along the entire East Coast, from New Hampshire to the Carolinas.