Tropical Storm Ernesto threatens Caribbean

WASHINGTON, Aug 26 (Reuters) The fifth tropical storm of the Atlantic hurricane season, Ernesto, could strengthen into a hurricane and threaten US oil and gas platforms in the Gulf of Mexico, forecasters said today.

At 5 a m (1430 IST), the center of Ernesto was about 415 km south of Santo Domingo, the Dominican Republic, and moving toward the west-northwest near 26 kph, the National Hurricane Center said.

Sustained winds were about 75 kph.

The system could drop 2 to 4 inches of rain over portions of Puerto Rico, the Virgin Islands, Jamaica and Hispaniola, the island shared by Haiti and the Dominican Republic, with possible isolated amounts of 8 inches.

A tropical storm warning is in effect for the south coast of Hispaniola and a tropical storm watch is in effect for Jamaica, the hurricane center said, adding that residents of the Cayman Islands and of western Cuba should also be on guard.

Tropical storms do not have powerful winds, but they can bring heavy rains that pose a danger for undeveloped nations, like Haiti, with poor building standards.

Energy traders also watched the storm because of the potential for it to strengthen as it neared the Gulf, where hurricanes temporarily knocked out much of U S crude oil and natural gas production last year. The Gulf provides about a quarter of U S oil and gas output.

The Miami-based hurricane center forecast that Ernesto would become a Category 1 hurricane, with 119-km-per-hour winds, by Monday, a day before the anniversary of Hurricane Katrina, which devastated New Orleans and killed about 1,500 people.

The Gulf waters this year are particularly warm. Warm waters are the fuel hurricanes need to gain power.

''Ernesto could become a potentially dangerous hurricane as it moves across the northwestern Caribbean Sea and the Gulf of Mexico,'' the hurricane center said in a bulletin on the storm.

REUTERS DKA VV1533