Sept. 1 (Bloomberg) -- Tropical Storm Felix formed near the Caribbean island of Grenada, becoming the sixth named storm of the 2007 Atlantic Hurricane season.

The system's maximum sustained winds strengthened to almost 40 miles (64 kilometers) per hour from 35 mph, the U.S. National Hurricane Center said in an advisory on its Web site at 5 a.m. Miami time today. The threshold for a tropical storm is 39 mph.

Felix was about 30 miles northwest of Grenada and was moving west at 18 mph at 5 a.m., the hurricane center said. Felix over the next five days may strengthen into a hurricane, with winds of at least 74 mph, as it tracks across the Caribbean, brushing Honduras before making landfall in Belize on Sep. 5, according to the center's five-day forecast.