"People are spending a lot of time talking about that," Fugate said of the convention. "I wish they'd be talking about making sure people in the (Florida) Keys are getting ready and that people in southwest Florida are getting ready," he told CNN.
The storm could also affect U.S. energy interests in the Gulf of Mexico, with analysts at Weather Insight, a Thomson Reuters company, giving it a 50 percent probability of moving into the heart of the oil and gas production region.
After passing through the Caribbean, Isaac is forecast to -strengthen again near Florida on Monday to a Category 1 hurricane, the lowest on the five-step Saffir-Simpson scale, but with an unclear path. Some computer models show the storm's track swinging farther west into the Gulf of Mexico.
"Significant uncertainty remains about the threat Isaac poses to Florida and other portions of the Gulf Coast," the U.S. National Hurricane Center said.
It said Isaac was centered about 190 miles (305 km) south-southwest of San Juan, Puerto Rico, on Thursday evening and was moving westward at 16 miles per hour (26 kph).