National Hurricane Center Director Bill Read says rainfall could reach eight inches in some spots as the system blows through Wednesday, causing localized flooding.
He predicts that the winds will be between 40 and 50 mph and doesn't think it will come close to reaching hurricane wind speeds of 74 mph.
A tropical storm warning has been issued for the Florida Keys, Florida Bay and from the southern tip of the peninsula through Palm Beach County. A tropical storm watch was in effect for Martin, St. Lucie and Indian River counties on the Atlantic coast and to just south of Marco Island on the Gulf coast.
A warning means that tropical storm conditions are expected within 36 hours and a watch means those conditions are possible within 48 hours.
School districts in Miami-Dade, Broward and Palm Beach counties were all planning to remain open Wednesday.
Bahia Honda, Curry Hammock and Long Key state parks in the Keys have been closed and the Florida Panthers have canceled their preseason hockey game Wednesday night against the Carolina Hurricanes.
At 11 p.m. EDT Tuesday, the depression's center was located about 290 miles south-southwest of Miami with maximum sustained winds of 35 mph. The threshold for tropical storms is 39 mph.
The storm was moving northeast at 8 mph.