NEWARK, N.J. >> Violent thunderstorms along the East Coast and a fire at an airport technical center in southern New Jersey combined to wreak havoc on flights around the country Friday night, leading one airline executive to tweet that “it will not be a pretty evening.”

The fire started at a little after noon at the William J. Hughes Technical Center at Atlantic City International Airport and forced the evacuation of 1,600 people who work at the complex, according to the Federal Aviation Administration.

The agency said the fire made some traffic flow systems unavailable, though it said the fire didn’t affect systems used to directly control air traffic. Traffic flow was moved to a backup system and performed manually during the transfer, the FAA said.

The system chiefly affected by the fire is used to automatically implement “ground stops” and “ground delays” — orders air traffic controllers may give to hold certain aircraft on the ground at airports instead of allowing them to take off as scheduled, or to delay their departure.

For example, if bad weather is causing a backup of planes trying to land at Northeast airports, FAA might order planes in Miami or Dallas or on the West Coast to hold on the ground until the backup is reduced. Since the fire disrupted the system that automatically implements grounds stops and delays, FAA personnel were calling airlines and air traffic control facilities around the country to issue the orders.

Rob Maruster, JetBlue’s chief operating officer, tweeted Friday, “It will not be a pretty evening, unfortunately.”

As of 7:30 p.m. EDT Friday, JetBlue had 66 flights that had either been delayed or canceled, but that number was expected to grow throughout the evening and into Saturday, said airline spokeswoman Jenny Dervin.

“That’s not a final number by any means,” she said.

Dervin attributed about half the JetBlue delays and cancellation to intense thunderstorms in the East and the other half to the FAA technical center fire.

For example, the fire disrupted some tower operations and flight management systems like metering — the automated arrival rate of aircraft into New York-area airports — which reduces the efficiency of airports and causes flights to back up, she said.

“It’s back-office support functions, but when it goes down — especially in bad weather — it just compounds the problem,” Dervin said.

Flight delays at New York’s three major airports — La Guardia, JFK and Newark Liberty — ranged from 80 minutes to 2  1/2 hours Friday evening. Severe thunderstorms swept through the area in the late afternoon, carrying 60 mph winds and dropping as much as five inches of rain in some parts of New Jersey.

In Atlanta, John Crenshaw, 46, had hoped to be in Britain in time to watch the Boodles, an exhibition tennis tournament in Buckinghamshire this weekend but was delayed on the tarmac at Hartsfield-Jackson Atlanta International Airport on Friday because of the fire in Atlantic City.

“I was supposed to go Atlanta to Boston and Boston to London, but we were still on the runway,” he told AP by phone from the airport, where he was waiting to board a Delta direct flight to London’s Heathrow Airport that was scheduled to leave at 10:45 p.m. EDT.

He said his initial flight never took off and that as it taxied back to the gate, the pilot announced “there was an FAA computer problem and that it was the most widespread one since 9-11.”

Though he won’t be able to make the Boodles — “That’s $350 bucks down the drain,” he said — Crenshaw did not despair, since he’ll be in London by tomorrow regardless.

“I’m going to Wimbledon,” he said. “I have center court tickets on Tuesday so that’s all that matters. As long as I am there by Tuesday I guess all is not lost.”