TAMPA // Tropical Storm Isaac was forecast to strengthen into a hurricane today as it bears down on the Florida Keys, disrupting energy output in the Gulf of Mexico and forcing a delay in the Republican National Convention.
The storm, the season's ninth named system, was projected to track across the Straits of Florida and then toward the south-eastern Gulf tomorrow, the US National Hurricane Center said.
The Florida governor, Rick Scott, declared a statewide emergency, with hurricane warnings in place for the Keys, Florida Bay and the coastline between Bonita Beach on the Gulf coast to Golden Beach in the east.
About 8.6 per cent of US oil production and 1.6 per cent of natural-gas output from the Gulf was closed down because of Isaac, a Bureau of Safety and Environmental Enforcement report showed.
The Republican convention, at which Mitt Romney is set to formally become the party's presidential candidate, will convene tomorrow as scheduled, but immediately recess until the next day.
Isaac may make landfall on the Gulf coast midweek. It was about 249 kilometres east of Havana, Cuba, yesterday evening and moving north-west at 32kph, with maximum sustained winds of 100kph. Mr Scott encouraged people planning to attend the convention to carry on, saying there was no need to cancel hotel reservations because of Isaac.
More than 50,000 people were expected to visit the Tampa Bay area for the Republican gathering, said James Davis, a convention spokesman. The venue, the Tampa Bay Times Forum, is in a mandatory-evacuation zone once storms reach Category 2 on the five-step Saffir-Simpson scale, according to the Hillsborough County Hurricane Guide.
Isaac dropped heavy rain in Haiti, where about 500,000 people are still living in temporary housing after a 2010 earthquake. At least three people died in the country.