Nov. 7 (Bloomberg) -- Hurricane Paloma strengthened into a Category 3 storm tonight as its winds lashed Grand Cayman Island, and forecasters said it may grow more powerful before hitting Cuba, still recovering from the impact of Ike and Gustav.

The Cuban government issued a hurricane warning for the central provinces of Sancti Spiritus, Ciego de Avila, Camaguey and Las Tunas, meaning sustained winds of 74 mph (119 kph) or more are expected in those areas within 24 hours, according to the U.S. National Hurricane Center in Miami. Residents were urged to rush preparations to protect lives and property.

The Cayman Islands are also under a hurricane warning. A hurricane watch, meaning similar conditions are expected within 36 hours, is in effect for the Cuban province of Granma, along with a tropical-storm warning.

Cuba ``will be devastated if it hits in the east,'' said Robert I. Rotberg, an author of books on Africa and the Caribbean and a professor of public policy at Harvard University in Cambridge, Massachusetts. ``It will destroy sugar.''

The storm may drop as much as 15 inches (38 centimeters) of rain on Cuba and the Caymans, and flash floods and mudslides are possible, especially in higher elevations, the center said.

A storm surge of as much as 7 feet, accompanied by battering waves, may hit the Caymans, while floods as high as 12 feet are expected when Paloma makes landfall in Cuba.

``Paloma continues to strengthen and now appears to be doing so at a quicker pace,'' hurricane specialists Eric Blake and James Franklin of the hurricane center wrote in a statement.

Travel Alert Issued

Paloma was designated a Category 3 storm with sustained winds of near 115 mph shortly before 7 p.m. Miami time, the center said. Earlier today the hurricane's winds were clocked at 75 mph. The storm is set to strengthen further and pass near the Caymans later tonight or early tomorrow before hitting Cuba, then weaken into a tropical storm Nov. 10.

The U.S. State Department issued a travel alert, warning Americans to ``consider carefully the risks of travel to areas that may be affected'' by Paloma, and to consider leaving if they don't have adequate shelter, according to a statement.

The hurricane was about 30 miles south of the eastern end of Grand Cayman and about 275 miles southwest of Camaguey, Cuba. It's moving north-northeast at 6 mph and is expected to turn to the northeast overnight, the center said.

Cuba Hit Hard

Hurricane Ike, which made landfall in eastern Cuba as a Category 3 storm in early September, killed four and prompted Cuban authorities to evacuate as many as 2 million people, or almost a fifth of the population. In late August, Hurricane Gustav hit the island with 150 mph winds, forcing evacuations.

Sugar is Cuba's top industry and its biggest commodities export, according to the U.S. Central Intelligence Agency's World Factbook. An estimated 386,967 acres (156,600 hectares) of sugar cane were flattened in the earlier storms, Reuters reported in September.

AccuWeather.com meteorologist Dale Mohler said Paloma should miss petroleum refineries in the Gulf of Mexico and in Saint Croix. The Gulf is home to about one-quarter of U.S. oil production.

The center's five-day projection shows Paloma crossing central Cuba and then moving over the central Bahamas and toward the open Atlantic Ocean early next week.

Paloma is the 16th named storm of the Atlantic hurricane season, which runs from June 1 to Nov. 30. Colorado State University researchers projected at least 17 major storms, including nine hurricanes, and the National Oceanic and Atmospheric Administration's Climate Prediction Center said there would be 14 to 18 named storms.

Hurricanes Bertha, Gustav, Ike and Omar reached major hurricane status of at least Category 3, with winds greater than 110 mph.

To contact the reporters on this story: Chris Dolmetsch in New York at cdolmetsch@bloomberg.net.

Last Updated: November 7, 2008 19:18 EST