Tropical Storm Isaac, the ninth named storm of the 2012 Atlantic hurricane season, sped toward the Leeward Islands Wednesday afternoon on an ominous path across the Caribbean toward the Florida coast.

According to the 2:00 p.m. EDT alert from the National Hurricane Center in Miami, the tropical storm was about 75 miles east of the island of Dominica with maximum sustained winds of 45 miles per hour. The fast-moving storm was headed west at 21 mph toward the Leeward Islands on a track near or south of the Virgin Islands and Puerto Rico on Thursday morning and en route to the Dominican Republic by Thursday night.

Tropical storm warnings are in effect across the Caribbean from Martinique to Puerto Rico. A hurricane watch, meanwhile, covers the Caribbean from the Virgin Islands across to the southern shore of the Dominican Republic. If Isaac continues on its projected course, it could weaken over Hispaniola and hit Cuba as a tropical storm before re-emerging south of Florida as a hurricane on Monday.

The menacing storm has already caused numerous travel disruptions and more are likely to come.

Liat, the major inter-Caribbean carrier, canceled 15 flights into and out of the Leeward Islands on Wednesday and said, pending the closure of several airports, that there will be further disruptions on Thursday. The airline will, however, allow passengers to change their flights free of charge for a period of one week from the date of their originally scheduled trip.

Caribbean Airlines, the region's other major carrier, has also canceled some of its flights in the Leeward Islands, though the airline has not released any official figures.

American Eagle, a subsidiary of American Airlines, said it has canceled eight flights to and from Miami along with eight flights to and from San Juan. A spokesperson for the airline said passengers affected by the storm can change their flights free of charge for dates through Aug. 28.

United Airlines will also wave change fees for its flights in and out of the Virgin Islands, Puerto Rico and the Dominican Republic for those scheduled to travel between Aug. 22 and Aug. 25.

JetBlue will waive all change and cancel fees and fare differences for customers traveling between Aug. 22 and Aug. 24 to all of its destinations from the Leeward Islands to the Dominican Republic.

Several regional ferries connecting the Leeward Islands have also ceased operation.

Cruises, meanwhile, have a different modus operandi. They rarely cancel trips, choosing instead to re-route voyages to destinations away from oncoming storms.

Royal Caribbean said in a statement that it was monitoring the path and progress of the storm, but it has yet to alter the itineraries of any ship that departs Thursday through Sunday. Norwegian Cruise Line, too, issued a weather alert saying it is monitoring the storm, but has not altered any schedules.

Carnival and Disney Cruises have not modified any of their sailings departing on or after Thursday, either, but the cruise lines said they are keeping a close eye on the storm.

If Isaac maintains its projected course, the cruise operators will likely make changes within the next 24 hours.

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