Very dangerous winds (75 mph+) may arrive around Sunday (10. September) afternoon.
Florida authorities have gone door to door to warn residents about the dangerous storm, sending throngs onto jammed highways as they fled north. More than 5.6 million people have been ordered to evacuate, Gov. Rick Scott said, and many coastal residents already have moved inland.
"If you have been ordered to evacuate, leave now -- not tonight, not in an hour, now," Scott said Friday night.
"This is as real as it gets," tweeted the National Weather Service. "Nowhere in the Florida Keys will be safe ... you still have time to evacuate."