Last Updated 8:25 p.m. ET
(CBS/AP) KEY WEST, Fla. - New hurricane warnings have been issued for an area stretching from Louisiana and New Orleans to the Florida Panhandle, as Isaac churned toward the Gulf of Mexico.
A hurricane warning has been extended along the northern Gulf coast, from east of Morgan City, La., to Destin, Fla., including metropolitan New Orleans, Lake Pontchartrain, and Lake Maurepas. A hurricane watch is in effect for east of Destin to Indian Pass, Fla.
Forecasters warn Isaac could be a strong Category 2 hurricane by the time it makes landfall.
The U.S. National Hurricane Center in Miami said Isaac is expected to hit somewhere between southeastern Louisiana and the Florida Panhandle either late Tuesday or early Wednesday.
Gov. Bobby Jindal called a state of emergency in Louisiana, and suggested that people leave low-lying parts of coastal parishes.
New Orleans Mayor Mitch Landrieu also declared a state of emergency Sunday afternoon, so that "everybody in the city of New Orleans can begin to prepare."
At 5:00 p.m. ET the center of Isaac passed just south of Key West, moving west-northwest at 16 mph. Maximum sustained winds were 60 mph.
The storm lashed the Florida Keys Sunday, bringing rain and strong winds.
While the worst of Isaac has already passed over the Keys, CBS News' Manuel Bojorquez said local officials are warning they are not out of the clear yet. Waves, wind and rain could continue to cause issues for locals.
A tropical storm warning remains in effect for Florida from Sebastian Inlet southward on the east Coast, and from Anclote Key southward on the west coast, as well as the Florida Keys, including the Dry Tortugas and Florida Bay, and Lake Okeechobee.
Tropical storm effects could be felt as far as 200 miles from Isaac's core in places like Miami, where more than 500 flights were cancelled and 8,500 people lost power Sunday.
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.
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.
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.