The National Hurricane Weather Service warned Hurricane Irma's turn north Saturday will be definitive. It will determine whether Tampa or Miami will get the strongest hit of the storm.
If it turns towards Miami, then Tampa residents will experience a Category 1-2 storm, and Miami will get the brunt of a Category 4-5 -- or vice versa.
By 11 p.m. Friday, Irma was a Category 5 storm with winds of 160-mph winds over Cuba.
Officials warned more than 5 million people that time was running out Friday night to evacuate ahead of the deadly hurricane, which was going to travel over one end of the state to the other.
"It's better to be safe than sorry," Miami-Dade Mayor Carlos Gimenez said about abiding by the evacuation orders.
Edward Rappaport, the NHC acting director, said the main concern for Florida is storm surge.
Gimenez said the evacuation orders were related to flooding. The advisory warned the deepest water will occur along the immediate coast in areas of onshore winds, where the surge and large breaking waves will raise water levels.
"I will probably inconvenience some people, but I want to make sure they will be safe," Gimenez said.
Forecasters adjusted the storm’s potential track more toward the west coast of Florida, away from the Miami metropolitan area of 6 million people, meaning "a less costly, a less deadly storm," University of Miami researcher Brian McNoldy said.
Nevertheless, forecasters warned that its hurricane-force winds were so wide they could reach from coast to coast, testing the nation’s third-largest state, which has undergone rapid development and more stringent hurricane-proof building codes in the last decade or so.
"This is a storm that will kill you if you don’t get out of the way," National Hurricane Center meteorologist Dennis Feltgen said. 'Everybody’s going to feel this one."