(CBS/AP) KEY WEST, Fla. - Tropical Storm Isaac gained fresh muscle Sunday as it bore down on the Florida Keys, with forecasters warning it could grow into a dangerous Category 2 hurricane as it nears the northern Gulf Coast.
Isaac drew new strength early Sunday during a warm-water crossing of the Florida Straits after causing weekend havoc in Cuba, where it downed trees and power lines. Before that, Isaac was blamed for seven deaths in Haiti.
The death toll in Haiti from the storm has risen to seven.
Gov. Rick Scott said in a news conference on Sunday that state, federal and local officials are coordinating efforts to make sure everyone is on the same page as Tropical Storm Isaac approaches Florida. he also said delegates visiting the Tampa area for the Republican National Convention will learn that in addition be being a great tourist destination, Florida is prepared to deal with hurricanes.
Scott noted there had been some minor power outages in South Florida as Isaac's feeder bands bring rain and wind to the area. He said the major concern in the Tampa Bay area will be wind. And as the storm approaches the rain-saturated Florida Panhandle, flooding may become an issue.
A small number of South Floridians - more than 8,000 customers - are already without power in Miami-Dade, Broward and Monroe Counties, according to CBS Station WFOR.
On Key West, locals followed time-worn storm preparedness rituals while awaiting the storm after Isaac swamped the Caribbean and shuffled plans for the Republican National Convention.
The U.S. National Hurricane Center said Sunday that Isaac had started lashing the Keys with rain and wind by late morning.
Isaac was expected to be at or near hurricane strength by the time its center reached the Keys later Sunday, the hurricane center said.
At 2:00 p.m. ET the storm was 50 miles south-southeast of Key West, moving west-northwest at 18 mph. Maximum sustained winds are 60 mph.
A hurricane watch issued for parts of the northern Gulf Coast, from the mouth of the Mississippi River eastward to Indian Pass, Fla., has been extended westward along the Louisiana coast to just east of Morgan City, including metropolitan New Orleans and Lake Pontchartrain.
The hurricane watch for the Florida east coast from Golden Beach southward to Ocean Reef is discontinued.
A hurricane warning is in effect for the Florida Keys including the Dry Tortugas, the west coast of Florida from Bonita Beach southward to Ocean Reef, and Florida Bay.
The tropical storm warning has been extended northward and westward along Florida's west coast and panhandle to Indian Pass.
A tropical storm warning is in effect for parts of Cuba and the Bahamas, Lake Okeechobee, and Florida's west coast and panhandle from north of Bonita Beach to Indian Pass, including Tampa Bay.
A steady line of cars moved north Saturday along the Overseas Highway, the only road linking the Florida Keys. Residents boarded up windows, laid down sandbags and shuttered businesses ahead of the approaching storm. Even Duval Street, Key West's storied main drag, was subdued for a weekend, though not enough to stop music from playing or drinks from being poured.
"We'll just catch every place that's open," said Ted Lamarche, a 48-year-old pizzeria owner visiting Key West to celebrate his anniversary with his wife, Deanna. They walked along on Duval Street, where a smattering of people still wandered even as many storefronts were boarded up and tourists sported ponchos and yellow slickers.
"Category None!" one man shouted in a show of optimism.
The Keys were bracing storm surge of up to four feet, strong winds and the possibility of tornadoes. The island chain's two airports closed Saturday night, and volunteers and some residents began filing into shelters.
"This is a huge inconvenience," said Dale Shelton, a 57-year-old retiree in Key West who was staying in a shelter.
Isaac has already left a trail of suffering across the Caribbean.
The storm's center made landfall Saturday near the far-eastern tip of Cuba, downing trees and power lines. In the picturesque city of Baracoa, the storm surge flooded the seaside Malecon and a block inland, destroying two homes.
An official at Haiti's Civil Protection Office said Sunday that the number of people who died in the Caribbean nation is now up to seven after an initial report of four.
Joseph Edgard Celestin had few details about how the people died. But he said one man was swept away as he tried to cross a river in the north of the country.
Also among the dead was a 10-year-old girl who had a wall fall on her. The government also reported "considerable damage" to agriculture and homes. Nearly 8,000 people were evacuated from their houses or quake shelters and more than 4,000 were taken to temporary shelters.
The Grise River in Haiti overflowed north of Port-au-Prince, sending chocolate-brown water spilling through the sprawling shantytown of Cite Soleil, where many people grabbed what possessions they could and carried them on their heads, wading through waist-deep water.
Scores of tents in quake settlements collapsed. In a roadside lot in Cite Soleil, the dozens of tents and shelters provided by international groups after the earthquake were tossed to the ground like pieces of crumpled paper, and the occupants tried to save their belongings.
After Isaac passes the Keys, it will move over the warm, open waters of the Gulf of Mexico and is expected to gain significant strength. It could ultimately make landfall on the northern Gulf Coast late Tuesday or early Wednesday. However, forecasters have stressed that the storm's exact path remains highly uncertain.
"Definitely the northern Gulf Coast should be preparing for a hurricane right now," Jessica Schauer, a meteorologist with the U.S. National Hurricane Center in Miami, told The Associated Press in a phone interview.
A Category 2 hurricane is capable of top sustained winds of 96 to 110 mph.
Isaac isn't likely to hit Tampa head-on, but it could still lash the city with rain and strong winds just as the convention ramps up. A tropical storm warning is in effect for parts of Florida's west coast, including Tampa Bay.
Convention officials said they would convene briefly on Monday, then immediately recess until Tuesday afternoon, when the storm is expected to have passed. Florida Gov. Rick Scott, a Republican, declared a state of emergency and canceled his plans to attend convention events on Sunday and Monday.