A red flag, warning of unsafe conditions, is seen on a pier in advance of Hurricane Michael in Pensacola, Florida, U.S. October 9, 2018.
Gulf Breeze, Fla. -resident Cathy Gaudette told FOX10 she was getting gas in Alabama along Interstate 10 before heading back to prepare her home for Michael.
Michael is predicted to become a category 3 storm, marked by torrential rains and winds in excess of 110 miles per hour.
Panama City's Bay County and other counties used their social media channels to alert residents about shelter openings.
"A potentially catastrophic event is developing", the National Weather Service forecast office serving the Tallahassee area wrote. The NHC said that it could hit anywhere along the Florida Panhandle or Florida Big Bend area.
The eye of the storm was 45 miles south-southwest of Macon, Ga., as of the NHC's 11 p.m. EDT update.
Parts of western Cuba, which was hit by the storm on Monday, were forecast to receive up to a foot of rain. Up to a foot of rainfall (30 cm) is forecast for some areas.
According to the Associated Press, six people were killed in Honduras, four in Nicaragua and three in El Salvador.
Bay County Sheriff Tommy Ford said he's "not seeing the level of traffic" he would expect when three-quarters of the county's residents are under mandatory and voluntary evacuation orders.
Panama City could see a storm surge at depths from 6 to 9 feet. "I'm blessed to have a place to come", she told Reuters.
Scott also warned that areas to the south will likely feel the effects of Hurricane Michael.
The weekend before Irma made landfall, Scott minced no words: "If you have been ordered to evacuate, you need to leave now", he said.
Storm surge and tropical storm-like conditions could impact Manatee County through Thursday afternoon, according to watches from the National Weather Service.
Some of the storm's most significant early impact was to offshore energy production. USA producers in the Gulf cut oil production by about 40 percent and natural gas output by 28 percent on Tuesday, the Bureau of Safety and Environmental Enforcement said.
Alabama is under a statewide state of emergency ahead of the hurricane, along with 92 counties in southern Georgia and 35 counties in Florida.
The Florida governor called Michael "a monstrous storm" and urged residents to listen to officials. Those who stayed emptied grocery store shelves of water and other supplies.
A hurricane hunter plane that bounced into the swirling eye of Michael off the western tip of Cuba late Monday found wind speeds were rising even as forecasters warned the storm could reach major hurricane status with winds topping 111 miles per hour (179 kph) by Tuesday night.