Tropical Storm Isaac, not yet at hurricane strength, was bearing down on the Dominican Republic’s south coast last night, according to the National Hurricane Center, with other Caribbean islands in the region also in its path. The storm dumped heavy rains on the Leeward Islands and forced the re-routing of a handful of cruise ships, including Royal Caribbean’s Allure of the Seas, as storm watches were posted in Puerto Rico and the U.S. and British Virgin Islands. The storm was forecast to become a hurricane by Thursday, as it neared the coast of Hispaniola.

Carnival Cruise Lines cancelled the Carnival Valor’s scheduled Aug. 24 call to Curaçao and replaced it with a visit to Nassau on Friday from 11 a.m. to 6 p.m. Also, due to high winds and heavy swells, the Carnival Liberty cancelled the call into Grand Turk today, Aug. 23, and replaced it with a visit to Nassau on Friday from 10 a.m. to 6 p.m. Royal Caribbean International’s current Aug. 19 sailing of Allure of the Seas is operating a Western Caribbean route instead of the Eastern Caribbean. The ship will visit Falmouth, Jamaica, and Cozumel instead of St. Thomas and St. Maarten.

While U.S. media focused mainly on the possibility that the storm would eventually hit the west coast of Florida around Tampa, where the Republican Convention is set to begin this weekend, travel agents and their clients were more interested in what islands in the Caribbean might be affected.

Isaac, with maximum sustained winds of 45 mph, has led to a hurricane warning being issued for the south coast of the Dominican Republic from Isla Soana westward to the Haiti-Dominican Republic southern border. A tropical storm warning is in effect for Martinique, Dominica, Guadeloupe and the surrounding islands of St. Martin/St. Maarten, St. Kitts, Nevis, Antigua, Barbuda, Montserrat, Anguilla, Saba, St. Eustatius, the British Virgin Islands, Puerto Rico, Vieques, Culebra and the U.S. Virgin Islands. A hurricane watch also is in effect for the north coast of the Dominican Republic from the Haiti-Dominican Republic Northern border eastward to north of Isla Saona.

A hurricane warning means that hurricane conditions are expected somewhere within the warning area typically within 48 hours. A tropical storm warning means that tropical storm conditions are expected within the warning area within 36 hours.

The center of Tropical Storm Isaac was moving at roughly 21 mph toward the west, a general motion that is expected to continue for the next couple of days. The storm is forecast to move away form the Leeward Islands and pass near or south of the Virgin Islands and Puerto Rico on Thursday, then approaching the Dominican Republic on Thursday night and Friday.

Ironically, despite predictions of an above-normal Atlantic hurricane season in 2012, travel insurance provider Travel Guard said 63 percent of travelers polled still plan to travel to destinations within the hurricane belt during this time. Of those, 36 percent plan to travel after September 1, typically the most active period of the hurricane season.