MIAMI, Florida (CNN) -- Tropical Storm Gustav struck Jamaica with pounding rain and winds just short of hurricane strength Thursday night, and Haitian officials raised their death toll from the storm to more than 50.
Forecasters said they expect the storm to churn over western Jamaica, regain hurricane strength and move near the Cayman Islands on Friday and approach western Cuba on Saturday.
Heavy winds rocked cars and trees in Kingston, Jamaica's capital, but there was little sign of damage. Streets were largely empty except for police, residents said.
"It's black out there," said Eldon Bremner, general manager of the Pegasus Hotel in the New Kingston district. But he said the rain "comes and goes" and added, "Kingston is doing all right."
Jamaica's government had evacuated people from surrounding islands and prepared to move residents out of low-lying areas ahead of the storm, a military spokesman said.
Meanwhile, oil companies began to pull workers off drill rigs in the Gulf of Mexico, and Mississippi joined Louisiana in declaring a state of emergency as forecasters warned of a U.S. landfall next week.
As Gustav crawled across the Caribbean, Tropical Storm Hanna formed out of a tropical depression northeast of Puerto Rico on Thursday, the eighth named storm of the Atlantic hurricane season.
Gustav had moved over Jamaica's eastern tip by 5 p.m. ET. Six hours later, Gustav's center was moving west along Jamaica's south coast with top sustained winds near 70 mph (112 kph), just below the 74-mph (119 kph) threshold of a minimal hurricane, according to the National Hurricane Center in Miami, Florida.
The storm, moving west near 7 mph (11 kph), was centered about 35 miles (56 kilometers) west-southwest of Kingston, the hurricane center said. See Gustav's projected path »
Hurricane warnings were in place for Jamaica and the Cayman Islands, 275 miles (443 kilometers) to the northwest of the storm's center.
Gustav hit Haiti as a hurricane Tuesday. On Thursday, Haiti raised its death toll from 14 to 51, said Pierre Louis Pinchinat, deputy director of the civil defense directorate.
In the Dominican Republic, which shares the island of Hispaniola with Haiti, authorities said a mudslide triggered by heavy rain killed eight people in Santo Domingo early Wednesday. iReport.com: Storm takes young lives in Santo Domingo
Pinchinat said that about 6,500 people in Haiti were living in shelters as of Wednesday, though some had returned to their homes Thursday. Watch flooded streets and damage in Haiti »
Gustav lost strength in the Hispaniola strike, falling back to tropical-storm status, but the hurricane center predicted that Gustav would regain strength, cross Jamaica and become a hurricane again Friday.
The storm is expected to produce rainfall amounts of 2 to 4 inches over southern Cuba and 6 to 12 inches over Jamaica and the Cayman Islands, with isolated maximum amounts of 25 inches possible, forecasters said. The heavy rain could trigger flash floods and additional mudslides.
Hurricane watches were posted for much of western Cuba, and a tropical storm warning was in effect for the southeastern Cuban province of Granma. Watch Cuba prepare for Gustav »
Gustav is expected to reach the Gulf of Mexico as a Category 3 hurricane Sunday or Monday, triggering alerts across the U.S. Southeast.
In Louisiana, where Hurricane Katrina struck three years ago, about 3,000 National Guard members began reporting for duty Thursday, and the state put another 2,000 on alert and has issued requests for assistance from other states if needed, Gov. Bobby Jindal said.
If the storm continues on its current track, evacuation calls could go out as early as this weekend, Jindal said.
Katrina killed more than 1,800 people when it struck August 29, 2005, scouring Mississippi beach towns down to bare sand and rupturing the protective levees around New Orleans, Louisiana.
The Bush administration's response to the storm was widely criticized, but David Paulison, director of the Federal Emergency Management Agency, said that FEMA is "not even the same organization it was three years ago."
"Certainly, Louisiana stands a fair likelihood of experiencing the first serious hurricane since the hurricanes of 2005," Homeland Security Secretary Michael Chertoff said in Maryland before heading to Baton Rouge, Louisiana. "Not an occasion for panic but an occasion to put into practice all the preparation that's been done up until now."
President Bush has discussed federal preparations for a possible Gulf Coast hurricane strike with top administration officials and still plans to speak Monday at the Republican convention in Minnesota, aides said Thursday.
White House spokeswoman Dana Perino said that Bush is keeping an eye on developments but that it is "premature" to discuss any changes to his schedule.
Authorities in Mississippi, Texas and Alabama also began activating storm plans and urging residents to keep an eye on the weather.
Forecasters said it was too soon to know the storm's path, but the National Hurricane Center's projection models show Gustav heading toward Louisiana. Some oil companies began evacuating workers off their rigs Thursday, spokesmen said, while other firms said they were were monitoring the storm's progress.
Farther east, a tropical depression that formed in the Atlantic early Thursday became Tropical Storm Hanna by late morning, forecasters reported. Forecasters project that Hanna will veer northwest between the Bahamas and Bermuda in the coming days and could become a hurricane.
At 5 p.m. ET, Hanna's top winds were 40 mph (64 kph). The storm was centered about 400 miles (644 kilometers) east-northeast of Puerto Rico, moving west-northwest at 12 mph (19 kph).
CNN's Eric Marrapodi, Sean Callebs, Barbara Starr, Alanne Orjoux and Matt Smith contributed to this report.