Tropical storm Ian has strengthened into a Category 2 hurricane as it nears north-west Cuba, the US National Hurricane Center (NHC) said on Monday.
The hurricane center said the storm was expected to pass over western Cuba early on Tuesday.
The agency added it was expecting the storm to "become a major hurricane" with current maximum sustained winds of roughly 100 miles (around 160 kilometers) per hour.
"Heavy rainfall will spread across western Cuba through Tuesday," the NHC wrote in its update at 11:00 p.m. Eastern Time (0300 GMT/UTC) on Monday. "This will likely produce instances of flash flooding and possible mudslides in areas of higher terrain over western Cuba."
The NHC twice upgraded Ian's severity on Monday and predicts that the hurricane could reach Category 4 on the five-step scale by the time it reaches Florida.
Havana declares cyclone alert in six provinces
Havana declared a cyclone alert in its six most western provinces as the hurricane intensified.
"Given the continuing deterioration of the weather conditions... it was decided to establish from 0800 (1200 GMT) the Cyclone Alert Phase," said Cuban Civil Defense Staff, which is in charge of protecting people in the event of a disaster.
Cuba is expected to bear the initial brunt of the storm, with authorities suspending classes on Monday and evacuating residents Pinar del Rio province.
A hurricane warning was previously issued in two Cuban provinces, namely, Isla de Juventud and Artemisa, as well as in the nearby Cayman Islands.
Florida braces for wild weather
Meteorologists said Ian could potentially make landfall on the west coast of Florida by midweek.
On Sunday, Florida Governor Ron DeSantis declared a state of emergency in all 67 counties and urged residents to stock up on food, water, fuel and medicine. He also mobilized 2,500 National Guard members to help with the emergency response.
"Expect heavy rains, strong winds, flash flooding, storm surge and even isolated tornadoes," DeSantis told reporters.
rm, zc, msh/dj (AP, Reuters, AFP)