The 14th hurricane of a record-breaking 2005 Atlantic hurricane season had earlier weakened back into a tropical storm, with winds below the 74-mph (119-kph) threshold that categorizes a tropical storm as a hurricane.

"There are no clear reasons and I'm not going to make one up to explain the recent strengthening of Epsilon," hurricane forecaster Lixian Avila said in a bulletin on the Miami-based hurricane center's Web site. "I am just describing the facts."

The storm posed no threat to land and was expected to loop back to the southwest after a couple of days and dissipate.

The 2005 Atlantic hurricane season officially ended on Wednesday but it is not altogether unusual for tropical storms to form in December. In other ways, however, the 2005 season has been extremely unusual.

Epsilon, the sixth hurricane to occur in December since records began in 1851, was named like its four predecessors for a letter in the Greek alphabet after the official list of storm names for 2005 was exhausted.

This season saw the most tropical storms on record - 26 - and the most hurricanes, with 14. The highest number of hurricanes previously on record was 12, in 1969, and the highest number of named storms was 21, in 1933.

The long-term average is 10 storms per season, six of which become hurricanes.

This year also set a record of three Category 5 storms - the most powerful on the five-step Saffir-Simpson scale of hurricane intensity - including Hurricane Katrina, which devastated New Orleans and killed more than 1,200 in Louisiana and Mississippi.

Hurricane Wilma in October became the strongest hurricane ever observed in the Atlantic, and Vince in October the first tropical storm known to have come ashore in southern Spain.