A tornado watch has been issued for all of South Florida and the Keys until noon Sunday, the National Weather Service reports.
The watch extends from Titusville to Key West and into North Port.
About 11 million people are affected by the watch.
A few tornadoes are likely in the affected area, the NWS said, in addition to marble-sized pieces of hail and isolated gusts of wind up to 60 mph.
The severe weather is associated with Hurricane Irma.