(RALEIGH) --  Tropical Storm Isaac is aiming for Puerto Rico and the U.S. Virgin Islands on Thursday. Forecasters say Isaac could become a hurricane before heading toward Florida just as Republicans gather for their national convention.

Darin Figurskey is a meteorologist with the National Weather Service Forecast Center in Raleigh. He said North Carolina may be affected by the storm eventually. "We'll have to watch out here in the Carolinas in the middle part of next week for the potential for some heavy rain if some of the guidance holds and it track starts taking it and recurving it to the north and east," said Figurskey.

Tropical Storm Isaac is expected to become a hurricane as it approaches Haiti and the Dominican Republic late Thursday or early Friday.