Felix, the second hurricane of the 2007 season and the second after last month's Hurricane Dean to ramp up to Category 5 strength over the warm waters of the Caribbean, maintained its power overnight as it plowed swiftly westward on a course expected to graze the northern Honduran coast.
Category 5 hurricanes, which can cause catastrophic damage, are considered rare.
But there were four of them in the devastating 2005 Atlantic hurricane season, including Katrina, and having two of them in a row tear through the Caribbean this year is likely to underscore research showing that global warming may produce stronger tropical cyclones.
By 8 a.m., Felix was around 425 miles (685 km) east of Cabo Gracias a Dios on the Nicaraguan/Honduras border and speeding westward at 21 mph (33 kph), a brisk pace for a storm, the U.S. National Hurricane Center said.
It was a small storm, with hurricane force winds only extending out around 30 miles from its center. Tropical storm force winds could be felt 115 miles from the core where the most destructive winds are located.
As severe a threat as its ferocious winds might be its rains. Felix was expected to drop 5 to 8 inches (12.7 to 20.3 cm) of rain across northern Honduras and northeastern Nicaragua. In some areas as much as 12 inches of rain could fall, possibly producing dangerous flashfloods and mudslides.
In 1974, Hurricane Fifi killed up to 8,000 people in Honduras after grazing the Caribbean coast and dumping up to 24 inches of rain on the northern mountains, sending rivers over their banks.
Honduras posted hurricane warnings from Limon eastward to the border with Nicaragua and a hurricane watch from Limon westward to the border with Guatemala. A warning means hurricane conditions are likely within 24 hours and a watch means hurricane conditions can be expected within 36 hours.
Hurricane conditions were also likely over extreme northeastern Nicaragua, the Miami-based hurricane center said, and both Guatemala and Belize posted hurricane watches for their Caribbean coastlines.
Tropical storm alerts remained in effect for Jamaica and for the Cayman Islands, although Felix was expected to stay well to their south.
The main computer models used to predict a storm's future track had originally forecast that Felix would slam into Mexico's Yucatan Peninsula, like Dean, but most shifted southward overnight, taking the storm into Central America.
Whether Felix would be able to reemerge over the Bay of Campeche and strengthen again in the Gulf of Mexico was unclear.
The energy industry, skittish about storms since hurricanes in 2004 and 2005 toppled rigs, cut pipelines and flooded refineries, was monitoring Felix carefully.
But companies said they had yet to evacuate platforms in the Gulf of Mexico, where a third of U.S. domestic crude is produced and 15 percent of its natural gas.
The 2007 hurricane season, expected to be busy, is reaching its peak. Most storms come between August 20 and mid-October, with September 10 marking the statistical height of the season.