BATON ROUGE, La.—Tropical Storm Ida swirled toward a strike on Cuba on Friday showing hallmarks of a rare, rapidly intensifying storm that could speed across warm Gulf waters and slam into Louisiana as a Category 3 hurricane on Sunday, the National Hurricane Center warned. “The forecast track has it headed straight towards New Orleans. Not good,” said Jim Kossin, a senior scientist with The Climate Service. Ida posed a relatively low threat to tobacco-rich western Cuba, where forecasters predicted a glancing blow on Friday. The real danger begins over the Gulf, where forecasts were aligned in predicting Ida will strengthen very quickly into a major hurricane, reaching 115 mph (185 kph) before landfall in the Mississippi River delta late Sunday or early Monday, experts said. “Ida certainly has the potential to be very bad,” said Brian McNoldy, a hurricane researcher at the University of Miami. “It will be moving quickly, …