The 8/28 - 11AM update now has Tropical Storm Erika remaining a tropical storm, and the eye of the storm scraping the west coast of Florida, before turning north into Central and North Florida. You should continue to watch http://www.nhc.noaa.gov/ for updates of the storm over the weekend.
As of this time, there are no advisories for Florida, and the major threat has seemed to dissipated. According to the current maps, South Florida will start to feel effects overnight Sunday into Monday, and last throughout the day.
A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area.
A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours.