Up to 12 inches of rain could fall in Florida's Panhandle and Big Bend, southeastern Alabama and southern Georgia, while parts of the Carolinas - recently deluged by Hurricane Florence - and southern Virginia eventually could see up to 6 inches, the hurricane center said.
As the storm moved north it battered Mexico's Yucatan Peninsula and western Cuba with drenching rains and winds of up to 130km/h, forecasters said.
The US National Hurricane Center in Miami, Florida, warned on Tuesday that warm waters will probably further strengthen Michael before it makes landfall. After Hurricane Irma past year, 14 people died when a South Florida nursing home lost power and air conditioning.
"You can not hide from storm surge", Governor Rick Scott said Tuesday. "Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other risky conditions", the hurricane center said.
A fast and furious Hurricane Michael sped toward the Florida Panhandle on Tuesday with 110 miles per hour winds and a potential storm surge of 12 feet, giving tens of thousands of people precious little time to get out or board up.
Tallahassee Mayor Andrew Gillum says the rapid rise of Hurricane Michael led city officials to hold a "sobering" discussion about the potential impact the storm will have on the area.
At about 11:15 a.m., a Tropical Storm Watch was issued for Bamberg, Barnwell, Calhoun, Claredon, Lee, Orangeburg and Sumter counties, according to the NOAA.
Wednesday: Hurricane Michael's rain begins in earnest after midnight Wednesday, becoming heavier through the morning hours.
Peaton says he's working closely with the National Weather Service to provide accurate information and protective measures to his county, which faces the Gulf of Mexico and is especially vulnerable to any flooding produced by Michael.
Hurricane-force winds extend outward up to 40 miles from the storm's center, and tropical-storm-force winds extend outward up to 195 miles, forecasters said.
Tolls have been lifted in Northwest Florida to ease evacuation, and Scott said fuel distribution is being watched, though there haven't been "widespread fuel shortages or outages".
Tropical Storm Michael could hit Florida Gulf Coast as Category 2 hurricane
The rainfall could lead to "life-threatening" flash floods and mudslides in mountainous regions, the hurricane center said. The fast developing storm is now a Category 1 hurricane expected to strengthen as it nears Florida .
"You will see damage to infrastructure, you will see power outages, and services that we are used to will be interrupted due to Hurricane Michael", he said.
Eric O'Neal and his wife, Mariana, watch the waves as Hurricane Michael approaches land in Pensacola, Fla., on October 9.
Gov. Rick Scott reiterated his warnings Monday evening during a news conference in Escambia County, encouraging residents along the coast to follow any evacuations orders as soon as possible.
A Hurricane Warning is in effect for.
A Royal Caribbean cruise ship, Empress of the Seas, got caught in the outer bands of Hurricane Michael.
Hurricane-force winds and strong rain were being felt in Cuba.
"I've been talking to mayors, to county commissioners, I think people are taking this serious", Scott said.
Florida State University announced it was closing for the week on Tuesday, along with schools in Leon County, home to the state capital Tallahassee.
Kemp said the bill totaled over $800 when she and her family fled Hurricane Irma's uncertain path a year ago.
Life-threatening storm surge is forecast along portions of the Florida Gulf Coast regardless of the storm's exact track or intensity.
Hurricane Michael will be a major hurricane when it arrives at the Florida coast sometime Wednesday, the National Hurricane Center says.