Aug. 18 (Bloomberg) -- Hurricane Dean, forecast to increase in intensity, roared past Puerto Rico today, plowing its way west through the Caribbean Sea toward the Dominican Republic, Haiti and Jamaica.

The storm is expected to reach Category 5, the highest level for tropical weather systems, and enter the Gulf of Mexico by Aug. 21, U.S. National Hurricane Center meteorologists said. Hurricane Katrina was a Category 3 storm when it hit New Orleans, costing insurers $57.9 billion in Gulf Coast damage.

``The Category 5 winds we're expecting later this weekend will cause complete devastation,'' said Bobbie Berg, meteorologist at the National Hurricane Center in Miami. ``The winds are so strong that virtually no structures can withstand it.''

The U.S. Agency for International Development has $2 million in commodities warehoused in Miami that will be distributed to Jamaica, which is expecting as much as 20 inches (51 centimeters) of rain. Relief supplies -- including water containers, medicine, plastic sheeting, generators and disaster kits -- will be airlifted for 32,000 people.

Space Shuttle

President George W. Bush, meanwhile, approved a pre- landfall emergency declaration for Texas at the request of Governor Rick Perry, White House spokesman Gordon Johndroe told reporters in Crawford, Texas. Federal Emergency Management Agency officials were coordinating with their counterparts in Mexico in anticipation of the storm.

``Our first priority is what's going on here in the United States, and FEMA is taking quick action now,'' Johndroe said.

Maximum sustained winds were about 150 miles an hour (240 kph), with higher gusts expected. Dean's center was about 455 miles (732 kilometers) east-southeast of Kingston, Jamaica, heading west-northwest at 18 miles an hour, a National Hurricane Center advisory said at 5 p.m. New York time.

The U.S. National Aeronautics and Space Administration is also preparing for Dean. The space agency shortened today's spacewalk by two hours to get ready for a shuttle landing on Aug. 21, one day earlier than previously scheduled.

Caribbean Warnings

A Category 4 hurricane on the five-step Saffir-Simpson scale has sustained winds between 131 and 155 mph; a Category 5 is a storm with winds higher than 155 mph.

``Jamaica is the next land mass that is looking at a strong likelihood of a direct hit,'' according to Dennis Feltgen, a meteorologist and spokesman for the Hurricane Center.

A hurricane warning remains in effect for Jamaica, the south coast of the Dominican Republic and Haiti. The Cayman Islands are now under a hurricane watch, the center said. A warning means the storm is expected within 24 hours and a watch indicates it's expected within 36 hours.

``We are evacuating all of our guests right now, everyone's at the airport,'' Cassandra Morgan, a security officer at the Sandals resort in Montego Bay, Jamaica, said in an interview this morning.

Delta Air Lines is operating extra flights into Jamaica and Grand Cayman to assist with evacuation efforts, the company said in a statement today. It's also allowing customers booked on flights to or from select cities in Mexico and the Caribbean to make itinerary changes without penalty.

Jamaica, Mexico Prepare

Jamaica's Office of Disaster Preparedness and Emergency Management advised people along the coast or in low-lying areas to have a plan for heading to higher ground.

Residents have been stocking up on groceries, gas and other supplies, ready to weather the storm, Morgan said. The island is bracing itself for a Category 5 storm.

``After the storm hits Jamaica and Haiti, it looks like the Yucatan Peninsula could be facing winds over 160 mph,'' Berg said. ``Anyone vacationing in Cancun can expect some rocky weather.''

Non-emergency U.S. State Department staff and families are allowed to move to Mexico City to escape the storm.

``The Department of State recommends that the U.S. citizens in Quintana Roo, Yucatan, and Campeche prepare themselves,'' the advisory said.

State of Emergency

Mexico's interior ministry today said the southeastern states of Quintana Roo and Yucatan are on ``yellow alert,'' the third-highest on a five-level scale, on expectations Hurricane Dean may hit their coastlines. The ministry said it was ready to provide funds to the area, if hit.

``You do not have to be a meteorologist to see that Dean has become a massive monster,'' Ken Clark, AccuWeather Inc. meteorologist, wrote on his blog.

Clark predicts the storm will move west-northwest to the south of Brownsville, Texas, in the Gulf of Mexico.

Louisiana GovernorKathleen Babineaux Blanco has declared a state of emergency and has asked President Bush to also declare an emergency, which could make federal aid available. The state's Emergency Operation Center will run 24 hours starting today, the governor said in a statement today.

The Gulf of Mexico accounts for about 27 percent of U.S. oil production and 15 percent of gas output, according to U.S. Energy Department figures. Transocean Inc., the world's largest offshore driller, said it will evacuate its most westerly rig in the Gulf of Mexico as a precaution for Hurricane Dean.

To contact the reporter on this story: Kelly Riddell in Washington at kriddell1@bloombergn.net

Last Updated: August 18, 2007 18:08 EDT