Last update: 10:25 p.m. EDT on Tuesday, Sept. 11. 

WEDNESDAY'S UPDATE: Airlines have canceled hundreds of flights in the Southeast ahead of Hurricane Florence. Nationwide, more than 550 flights have been canceled from Wednesday through Friday, flight-tracking service FlightAware counted as of 7:20 a.m. ET.  Full update here

LAST UPDATE FROM TUESDAY:  The first flight cancellations for Hurricane Florence have begun as the storm continues to track toward the Carolina coast. 

Already, more than 135 flights have been pre-emptively canceled for Wednesday and another 264 for Thursday, FlightAware.com reported at 10:25 p.m. EDT on Tuesday. Friday's cancellations had not yet been posted to FlightAware, but though that count also was likely to already be into the hundreds. 

Many of the cancellations announced by Tuesday night came at airports along the coast, where some airports announced plans to reduce or halt flight operations ahead of Florence’s expected landfall. 

However, the cancellation tally was likely to soar much higher as Florence tracked nearer. 

For now, North Carolina’s Pitt-Greenville Airport was among the first to say schedules would be reduced. Officials told WNCT-TV that flights there would end by midmorning Wednesday. 

In South Carolina, officials at Charleston International – the busiest on the coast of the Carolinas – said no flights would operate Thursday or Friday, according to The Post and Courier of Charleston. Flights were tentatively expected to resume after 7 a.m. Saturday. 

Already, Southwest Airlines had suspended all of its operation there as of midday Tuesday. 

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In New Bern, North Carolina, the city’s Coastal Carolina Airport said via Facebook that Wednesday flights would be reduced and that no flights would operate on Thursday or Friday.  

Similar reports were coming in from other airports along the Carolina coast. 

So far, the pre-emptive cancellations for Wednesday and Thursday were spread across a number of carriers, including American, Southwest, United, Allegiant and Frontier. 

For Wednesday, more than 50 combined arrivals and departures had been canceled at Charlotte, a major hub for American. Many of those were to smaller coastal airports where schedules were already being reduced. 

Southwest also had preemptively halted operations at several other airports in the Carolinas, in addition to Charleston. The carrier said it would not operate at all on Thursday and Friday at Raleigh/Durham and Norfolk. Southwest's Richmond flights will be suspended "midday" Thursday through early Saturday.

More broadly, travelers should expect airlines to begin cancelling large blocks of flights, with more announcements coming either late Tuesday or Wednesday morning. 

Next update: By 8 a.m. ET on Wednesday, Sept. 12

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