A forecast for Hurricane Irma has shifted the trajectory of the mega-storm slightly westward, which may mean direct hits on the Florida Keys and worst-case scenarios for the cities of Naples, Fort Myers and possibly Tampa.
As of late Friday East Coast time, modeling from the NBC Weather Unit now expects catastrophic wind and storm damage in the Keys early Sunday morning. Marco Island, Naples, Cape Coral and Fort Myers are likely to be struck later on Sunday.
A shift west would still mean that the east coast of Florida still sees hurricane gusts and damage, NBC said, but it makes catastrophic effects less likely from Miami northwards.
Irma, one of the most powerful Atlantic storms in a century, has already lashed the Caribbean with devastating winds and torrential rain, leaving behind at least 21 deaths and a swath of destruction.
Irma was more than 300 miles southeast of Miami on Friday, after soaking the northern coasts of the Dominican Republic and Haiti and pummeling the Turks and Caicos Islands.
The “extremely dangerous” hurricane was downgraded from a category 5 to a category 4 early on Friday, but it still packed winds as strong as 155 miles per hour, the U.S. National Hurricane Center (NHC) said in an advisory.
The storm was last spreading westward over portions of Cuba and the central Bahamas, the NHC said.
In Miami, hundreds lined up for bottled water and cars looped around city blocks to get gas on Thursday. Gasoline shortages in the Miami-Fort Lauderdale area worsened on Thursday, with sales up to five times the norm.
In Palm Beach, the waterfront Mar-a-Lago estate owned by U.S. President Donald Trump was ordered evacuated, media said. Trump also owns property on the French side of Saint Martin, an island devastated by the storm.
Dozens of cities and counties in increasingly-northern regions of Florida are issuing mandatory and voluntary evacuations, many of which are already being executed. Some highways have ground to a halt from congestion as evacuees flee the most dangerous hurricane areas.
A mandatory evacuation on Georgia‘s Atlantic coast was due to begin on Saturday, Governor Nathan Deal said.
— NBC News’ Bill Karins, CNBC’s Kevin Breuninger and Spencer Kimball, and Reuters contributed to this report