Tropical storm Michael strengthened to a Category 1 hurricane Monday as it barreled toward the U.S. Gulf Coast packing maximum sustained winds of 120 kilometers per hour, meteorologists said.
The weather system was located between Mexico's Yucatan peninsula and the west coast of Cuba by 3 p.m. and was heading slowly towards the northern Gulf Coast of Florida, the National Hurricane Center (NHC) in Miami said.
It is expected to be a major Category 3 hurricane by the time it hits Florida on Wednesday, before moving northeast across the southeastern United States through Thursday.
"#Michael could produce three life-threatening hazards along portions of the northeastern Gulf Coast: storm surge, heavy rainfall, and hurricane-force winds, with storm surge and hurricane watches in effect," the NHC said on Twitter. "Residents in these areas should follow the advice given by local officials."
Heavy rainfall from Michael could produce "life-threatening flash flooding," the NHC said, from the Florida Panhandle and Big Bend region into portions of the Carolinas through Thursday.
The first rains from Michael were already beginning to soak the Florida Keys on Monday, with up to 10 centimeters expected to fall through Tuesday.
Florida Governor Rick Scott declared a state of emergency for 26 counties.
"We are running out of time," the Republican governor said on Twitter. "TODAY is the day to get a plan, because tomorrow could be too late." "This storm will bring torrential rain, heavy winds and dangerous storm surges to many areas of our state," he tweeted. "EVERY FAMILY must be prepared. We can rebuild your home, but we cannot rebuild your life," Scott added.
Florida State University announced it was closing for the week Tuesday, along with schools in Leon County, home to the state capital Tallahassee.
Tallahassee's Democratic mayor Andrew Gillum, who is campaigning to succeed Scott as governor in next month's elections, suspended his campaign and returned to the state capital to oversee storm preparations.
The Carolinas are on the long recovery from Hurricane Florence, which left dozens dead and is estimated to have caused billions of dollars in damage last month.
It made landfall on the coast as a Category 1 hurricane on September 14 and drenched some parts of the state with one meter of rain.
Last year saw a string of catastrophic storms batter the western Atlantic — including Irma, Maria and Hurricane Harvey — causing a record-equaling US$125 billion in damage when it flooded the Houston metropolitan area.
For this hurricane season, the U.S.-based National Oceanic and Atmospheric Administration forecasting service and Britain's Met Office predict between five and nine storms of Category 3 or stronger.
At their most fearsome, these low-pressure weather fronts pack more power than the energy released by the atomic bomb that leveled Hiroshima.
As the storm moved north it battered Mexico's Yucatan Peninsula and western Cuba with drenching rains and winds of up to 130 kph, the Miami-based hurricane center said.
Heavy rains and flash-flooding over the weekend caused 13 deaths in Central America after Michael formed off the coast of northern Honduras.