The NHC has put out a hurricane warning and a tropical storm warning stretching through nearly all of Florida into Georgia and SC, home to more than 20 million people.
- More than 1.43 million electric customers across 24 counties are without power, Florida Power and Light said Sunday morning.
At 11 p.m., Irma's maximum winds had increased slightly to around 120 mph, with hurricane-force winds extending outward from the eye for 70 miles.
Irma, which killed at least 22 people as it tore through Caribbean islands toward Florida, has already claimed at least one life in the state.
Antigua and Barbuda were spared from the worst of Jose, as it skirted north of the island on Saturday and was downgraded to a tropical storm warning.
"There is a serious threat of significant storm surge flooding along the entire west coast of Florida", Governor Rick Scott told a press conference.
"Let's show Irma that we shoot first", the event description says.
Meanwhile, Scott acknowledged the fuel shortage that Irma had caused will likely continue, despite the state's efforts to ensure extra supply.
Inga Beale, chief executive of insurance market Lloyd's of London, warned that the string of storms battering the U.S. and Caribbean coasts this month could rack up losses of $200bn (£151bn) for insurers.
The hurricane center also emphasizes that Irma will bring life-threatening wind to much of Florida regardless of the exact track of its center.
After slamming the keys, Irma on Sunday afternoon is expected to move along or near the southwest coast of Florida, the hurricane center said.
There were no immediate reports of casualties. It submerged the highway that connects the isolated Florida Keys archipelago with the mainland and small whitecapped waves could be seen in flooded streets between Miami office towers. The National Weather Service reported wind gusts of 90 miles per hour (145 kph) near its Key West office.
"What happened was the storm continued - after interacting with Cuba - to move west-northwest", Jones said.
"With a storm of this magnitude, there will be widespread destruction throughout our service territory, and most of it will be in the most densely populated areas of South Florida", the utility's CEO, Eric Silagy, said in a statement.
There's also a chance that coastal areas of Gorgia, South Carolina, and North Carolina, will be affected by Irma.
With Fema still dealing with the aftermath of Hurricane Harvey in Houston, Irma could test the agency's ability to handle two disasters at the same time. Forecasts originally said the storm would hit the city directly, but Irma took a westward turn. "You need to be afraid of the storm surge!"
In downtown Miami, one of two dozen construction cranes looming over the skyline collapsed atop a high-rise in Irma's winds. "As soon as the storm passes, we will work to open those ports and get fuel here", he said.