DENVER (MarketWatch) -- The Republican Party may hold off on its national convention next week if Tropical Storm Gustav turns into a hurricane and strikes the Gulf Coast, a spokesman for presumptive presidential nominee John McCain said Thursday.

Gustav was gaining momentum off the coast of Jamaica and headed on a trajectory toward New Orleans, which was hit three years ago Friday by Hurricane Katrina. If it strikes the Gulf Coast by Monday, that would occur right as the GOP is convening its quadrennial gathering in St. Paul, Minn., on the heels of the Democratic convention this week.