Tropical Storm Isaac lashed south Florida with winds and heavy rain on Sunday after battering the Caribbean, disrupting plans for the Republican National Convention in Tampa and threatening to interrupt about half of U.S. offshore oil output.
Isaac is expected to strengthen to a Category 2 hurricane and hit the Gulf Coast somewhere between Florida and Louisiana at midweek - on or near the seventh anniversary of Hurricane Katrina - the U.S. National Hurricane Center said in an advisory.
A hurricane watch was extended westward to include New Orleans, which was devastated when Katrina struck the city on August 29, 2005, killing more than 1,800 people and causing billions of dollars of damage to the Gulf Coast.
Isaac is due to be at or near hurricane strength when its center crosses the Florida Keys late on Sunday, the Miami-based hurricane center said. A storm becomes a hurricane when sustained winds reach a minimum of 74 miles per hour.
It would be the first hurricane to hit Florida in seven years and the NHC said the storm was expected to strengthen to a Category 2 hurricane, with maximum sustained winds of 105 miles per hour, as it swept up the Gulf of Mexico.
At 11 a.m. EDT (1500 GMT) on Sunday, Isaac was about 80 miles east-southeast of Key West and packing top sustained winds of 65 miles per hour, according to the Miami-based NHC.
More than half of the restaurants and other businesses were shuttered in the tourist haven of Key West on Sunday, at the southernmost tip of the U.S. mainland, after many visitors heeded official warnings to head home early.
Gulf of Mexico oil operators on Sunday braced for the first hurricane to affect the U.S. oil patch in 2012, which could shut down of more than half of U.S. offshore oil output. Isaac's more westerly expected track brings it closer to the heart of the U.S. offshore oil patch, which produces about 23 percent of U.S. oil output and 7 percent of its natural gas output.
So far, Isaac has shut about 9 percent of offshore oil output, according to U.S. officials. That number will rise in coming days, according to forecasters at Weather Insight, an arm of Thomson Reuters, who predict the storm will spur short-term shut-downs of 51 percent of U.S. offshore oil capacity and 52 percent of its natural gas output.
London-based BP Plc, the biggest U.S. Gulf producer, said it will shut production at all of its Gulf of Mexico oil and gas platforms and evacuate all workers on Sunday.
REPUBLICAN CONVENTION SCHEDULE DISRUPTED
Republicans, who will formally nominate former Massachusetts Governor Mitt Romney as their presidential candidate for the November election, will convene their four-day meeting on Monday as scheduled, then recess until Tuesday.
In its latest advisory, the NHC said Isaac was churning west-northwest at 18 miles per hour. The storm was officially expected to make landfall anywhere between the Florida Panhandle and eastern Louisiana early on Wednesday as a Category 2 hurricane, capable of causing extensive damage due to extremely dangerous winds.
Tampa, located on Florida's west coast, faces a threat of both winds and heavy rains from Isaac, according to NHC meteorologist David Zelinsky.
"For the Tampa area, storm surge values could be three to five feet above ground," Zelinsky said, referring to the threat of storm-driven inundations of the city from Tampa Bay.
In Haiti, Isaac added to the misery of more than 350,000 survivors of the 2010 earthquake still living in flimsy resettlement camps as water gushed into tents and corrugated plastic shacks ripped apart by the wind.
FLOODING AND DEATHS IN HAITI
Authorities in the impoverished nation said on Sunday the storm had killed seven people in Haiti, including a 10-year-old girl killed when a wall fell on her and a woman crushed to death by a falling tree.
In the Dominican Republic, officials said three people were missing, including the mayor of a town near Santo Domingo swept away as he tried to save another person from a flooded river.
No deaths or injuries were reported in Cuba, which got off lightly when the storm crossed its eastern flank instead of raking up the length of the island as originally predicted, but it still sustained damage.
Baracoa, the island's easternmost city, appeared to get the worst of the storm, which sent 13-foot (4-metre) waves crashing over the seawall and into the streets. Cuban TV reports said more than 1,000 people had to be evacuated and 50 buildings were damaged.
"The force of the waves has destroyed the farmer's market for small businesses, also the children's area of a park and various homes," said Baracoa resident Olider Aguilera by telephone.
By Sunday afternoon much of Key West looked like a ghost town. But a few hardy tourists were staying put.
"We booked months in advance. The next thing I know we have a hurricane," said Diane Vaccaro, a grandmother from New Jersey vacationing with her sister and husband Andrew.
She said it would be her eighth hurricane.
"It's just fun. You ride it out and you can say 'I did it. I survived,'" said Vaccaro.