MIAMI -- Less than a day after making this hurricane season the second-busiest on record, the former Hurricane Vince began to break down Monday over the cooler waters of the far eastern Atlantic, forecasters said.

The former Category 1 hurricane weakened to a tropical storm with top sustained winds near 60 mph, said forecasters at the National Hurricane Center.

Hurricane Tracker | Hurricane Center

Vince was the 11th hurricane of the season, and the 20th named storm.

At 5 a.m. EDT, Vince was centered about 620 miles east-southeast of the Azores and about 145 miles north of the Madeira Islands. It was moving east-northeast at about 12 mph, and was expected to gradually pick up speed, according to the hurricane center.

Forecasters said it was moving toward Portugal and Spain, but likely wouldn't make landfall.

Vince's eye had disintegrated, and the storm was expected to dissipate within the next 24 hours, forecasters said.

Vince formed Sunday between the Azores and the Canary Islands in waters that are up to seven degrees cooler than the 80 degrees typically needed for a tropical storm, said Chris Sisko, a meteorologist at the hurricane center.

Only one other Atlantic season had more tropical storms and hurricanes since record keeping began in 1851 -- there were 21 in 1933. The most hurricanes to ever form in a season were 12 in 1969.

The hurricane season began June 1 and ends Nov. 30. Wilma is the only name left for storms this season. After that, storms are named after letters in the Greek alphabet -- which has never happened in more than 50 years of regularly naming storms.

This season has been one of the deadliest and costliest in the U.S. in the last century. Hurricane Katrina killed more than 1,100 people on the Gulf Coast and is expected to cause more than $34 billion in insured losses.

Forecasters say this appears to be the farthest east and north that a tropical storm has formed in recorded history in the Atlantic.