Aug. 28 (Bloomberg) -- Tropical Storm Gustav spun toward Jamaica today as residents of Louisiana began to prepare for the system to hit at hurricane force next week, three years after Katrina devastated New Orleans.

Gustav packed maximum sustained winds of almost 70 miles (113 kilometers) per hour at 2 p.m. Miami time and may regain hurricane strength of at least 74 mph today, the National Hurricane Center said. The system was 40 miles east of Kingston, Jamaica. As much as 25 inches (64 centimeters) of rain may fall in parts of Jamaica, Haiti and the Cayman Islands.

``This could be a Category 2 or 3 hurricane by the time it reaches the Cayman islands tomorrow or tomorrow night,'' Joe Bastardi, a meteorologist with private forecaster AccuWeather.com, said today on Bloomberg TV. ``Don't be surprised if this really lets loose and intensifies very rapidly once it gets west of Jamaica. This is a big deal coming.''

The storm, which already killed more than 20 people in Haiti and the Dominican Republic, prompted the evacuation of offshore oil workers in the Gulf of Mexico. Louisiana Governor Bobby Jindal posted a declaration of emergency on his Web site.

The system was heading west at 5 mph, and is forecast to move near or over Jamaica before heading past the western tip of Cuba this weekend. The current forecast shows Gustav making landfall in central Louisiana on Sept. 2.

FEMA on Alert

The Federal Emergency Management Agency was on alert and said it had food, water and supplies ready to move into the area. Jindal readied 3,000 National Guardsmen to help emergency efforts in Louisiana, and 700 buses were on standby to evacuate as many as 35,000 people.

``I anticipate that the effects of the storm will overwhelm the capability of state resources and it is necessary that critical pre-positioning and other readiness requirements be provided through federal assistance,'' Jindal wrote to President George W. Bush. ``Federal assistance is necessary to save lives and to protect property, public health and safety.''

The non-profit organizations that have been helping residents recover from Hurricane Katrina are holding an emergency meeting to discuss what they should do if Hurricane Gustav strikes the Gulf Coast, said Kate Barron, community specialist with aid agency Oxfam America.

``The same people who are trying to get back on their feet are the same communities targeted by Gustav,'' Barron said in an interview. ``So these communities are in a precarious situation.''

Evacuations Likely

If Gustav comes in as a Category 3 hurricane or higher, Barron said she expects all the residents in some parishes will need to be evacuated because shelters won't be able to withstand a storm of that magnitude.

In a televised interview yesterday, New Orleans Mayor Ray Nagin said there would be no ``shelters of last resort,'' such as the Superdome or the Convention Center, where thousands took refuge during Katrina. He said police will roam neighborhoods making sure people are out, and trains, buses and airplanes will be pressed into service for those needing transportation.

The city is planning a commemoration tomorrow for victims of Katrina, the most economically destructive hurricane in U.S. history. Katrina cost the Gulf coast states hit by the storm as much as $125 billion, according to the National Oceanic and Atmospheric Administration.

``Several thousand'' of the almost 20,000 workers on offshore platforms in the Gulf of Mexico, about a quarter of whom are needed to maintain production, were to be evacuated, Ted Falgout, director of Port Fourchon in Louisiana, said in an interview yesterday. The port is a staging area for rig workers.

Crude Falls

Crude oil for October delivery fell $2.84, or 2.4 percent, to $115.31 on the New York Mercantile Exchange at 1 p.m., after three days of gains.

Royal Dutch Shell Plc, BP Plc and ConocoPhillips evacuated drilling rigs along the coast in preparation for the storm. U.S. oil and gas platforms and pipelines are most concentrated in the waters south of Louisiana and east of Texas.

Offshore fields in the Gulf accounted for 26 percent of total U.S. crude production and 12 percent of natural gas output in April, according to the U.S. Energy Department.

As Gustav approached Jamaica, the entire island was under a hurricane warning, the U.S. center said. Jamaica today opened 16 emergency shelters and advised residents of low-lying areas to evacuate, the Office of Disaster Preparedness and Emergency Management said in an e-mailed statement.

In the Dominican Republic, eight people were killed and two injured in a landslide, the country's Center of Emergency Operations said on its Web site. Some 1,180 homes were destroyed or flooded across the south of the country, the center said. In neighboring Haiti, 15 were killed and 14 are missing, Radio Metropole Haiti reported on its Web site.

Tropical Storm Hanna formed today in the Atlantic northeast of the northern Leeward islands, the U.S. center said. The storm is on a path to head up the East coast of the U.S., computer models show.

To contact the reporters on this story: Robin Stringer in New York at rstringer@bloomberg.net; Ryan Flinn in San Francisco at rflinn@bloomberg.net

Last Updated: August 28, 2008 14:04 EDT