(CNN) — Intense thunderstorms close to Dallas-Fort Value Worldwide Airport on Wednesday brought about 100 American Airlines flight diversions and led to hundreds of cancellations that prolonged into Thursday’s timetable.

Additional than 300 American Airways flights had been canceled by midday Thursday, or 9% of its timetable, in accordance to flight monitoring web site FlightAware. A total of about 650 US flights experienced been canceled by midday ET.

On Wednesday, American canceled practically 370 flights. A whole of more than 1,200 US flights have been canceled on Wednesday, FlightAware knowledge displays.

DFW airport is American Airlines’ biggest hub.

Southwest Airways, headquartered in Dallas, logged about 250 cancellations on Wednesday, in accordance to FlightAware. Southwest experienced canceled about 100 Thursday flights as of midday ET.

Caught off guard by 2nd line of storms

According to American’s Chief Functioning Officer David Seymour, the airline organized for thunderstorms in the forecast south of the airport on Wednesday afternoon. But a further wave came by shock.

“Those storms then regenerated and made an solely new, and unanticipated, line of storms north of the airport. This unpredicted storm activity prevented all arrivals into DFW for a a few-hour period,” Seymour said in a memo to employees shared with CNN Journey.

One hundred AA flights have been diverted, and the airline proactively canceled all remaining flights into and out of DFW on Wednesday.

“DFW airport had gone 67 days devoid of looking at measurable rain, the next-longest streak on file — temperature like this can wreak havoc on our procedure. This was the worst storm we have witnessed at DFW this summer months, and to make issues even worse, there was no indicator it was on its way,” Seymour claimed.

He thanked American Airlines’ employees for their endeavours in recovering from the weather disruption and noted that cancellations are “massively impactful to our consumers.”

“Canceling flights is a final vacation resort,” Seymour reported in the memo to team. “But undertaking so in advance — even with a little window — presents prospects the very best probability to regulate their designs and stay away from final-moment concerns at the airport.”

DFW Airport claimed Thursday that it has resumed normal functions.

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