A state of emergency has been declared over a huge area in the Florida Panhandle and beyond, as weather experts warn of life-threatening storm surge and flash flooding.
Hurricane Michael is expected to make landfall in the Florida Panhandle on Wednesday morning and as a Category 3, with winds of 160km per hour, the US National Hurricane Center said.
Storm Michael was upgraded to a Category 1 hurricane on Sunday evening and has already hit parts of Mexico and Cuba. It could reach or be close to a Category 3 hurricane by Tuesday night or Wednesday.
A tropical storm warning is in effect in parts of Cuba as well as the coast of Mexico from Tulum to Cabo Catoche.
Gulf Coast residents have been told to prepare for evacuation orders and authorities have put more than 5,000 National Guard soldiers on alert.
Airlines have issued flight change waivers and services have been pre-emptively canceled.
Florida governor Rick Scott appeared on TV to say: "The storm will be life-threatening and extremely dangerous." He said the surge could affect areas of Florida not in the storm’s direct path.
About 300 miles of coastline are potentially in its firing line.
"Hurricane Michael isn’t heading to any one town," the National Weather Service tweeted.
Tropical storm watches were issued in Mississippi, Florida, Georgia and South Carolina.
After hitting Florida, Michael will move north-eastward along the Atlantic coast and there are warnings eight inches of rain could fall in northern Florida and through the Carolinas.
