A storm system in the eastern Atlantic Ocean strengthened into Tropical Storm Dean this morning, amid signs it could become a strong hurricane as it moves toward the Caribbean this weekend.
Some forecasters say Dean could menace the U.S. coast by next week.
The National Hurricane Center said Dean had top sustained winds of 40 mph at 5 p.m. and was expected to continue strengthening over the next 24 hours.
Meanwhile, hurricane specialists said an area of disturbed weather in the Gulf of Mexico appears poised to become a tropical depression and could cause problems for the Gulf Coast within a few days.
And in the Pacific Ocean, powerful Hurricane Flossie roared toward the big island of Hawaii, where it is expected to produce strong winds and flooding rains.
Tropical Storm Dean's center shortly before midday was 1,490 miles east of the Lesser Antilles, including the islands of Martinique, St. Lucia, St. Vincent and Grenada. Dean was moving briskly to the west, at 20 mph.
Hurricane specialist Lexion Avila said Dean is expected to continue moving westward for several days, gradually slowing its forward speed. But all computer models predict Dean will intensify into a hurricane.
The Hurricane Center's official forecast shows Dean as a 95-100 mph hurricane south of Puerto Rico on Sunday morning.
Dean is the first of this season's Cape Verde storms, named because they form in the warm eastern Atlantic waters south of the Cape Verde Islands. Those storms have produced some of the country's worst hurricanes.
Henry Marguity, a senior meteorologist with Pennsylvania-based Accu-Weather, said he thinks Dean will make landfall somewhere on the U.S. coast, between Wilmington and New Orleans. Marguity said he realizes his prediction covers a wide area, but Dean is too far from North America for a more specific forecast now.
Jeff Masters, a senior meteorologist with Michigan-based Weather Underground, said it is too early to predict a possible U.S. landfall. He said that if high pressure builds along the East Coast late this weekend, it would steer Dean toward Florida or the Gulf of Mexico. If low pressure builds along the coast, however, Dean would curve northward, perhaps targeting the Carolinas but also possibly curving away from the U.S. coast.
Don Sutherland, a New York-based meteorologist, said his studies have shown 11 storms have formed in August in the area where Dean became organized. Of those, nine became hurricanes - four of them becoming Category 3 or stronger on the Saffir-Simpson scale that ranks hurricanes in severity from 1 to 5.
Sutherland said most of the 11 storms curved away from the U.S. coast eventually, but three made U.S. landfall - including powerful Andrew, which devastated south Florida in 1992; and Frances, which hit Florida in 2004 and then curved inland, causing dozens of tornadoes and severe flooding across the central and western Carolinas.
Meanwhile, forecasters from the National Hurricane Center said a reconnaisance plane will fly this afternoon into the area of stormy weather north of Mexico's Yucatan Peninsula. That area appears to be forming into a tropical depression, and meteorologists warned that people living along the Gulf Coast - especially south Texas and Mexico - should watch the development of the system over the next few days.
In Hawaii, public schools were closed and Hawaiians were warned to have plenty of food and water on hand as Hurricane Flossie roared toward the state today.
The eye of the Category 3 storm, with maximum sustained winds of 110 mph, was expected to pass about 80 miles south of the southern edge of the big island of Hawaii about 10 p.m. (Eastern time) today.
- The Associated Press contributed to this story.