MIAMI (September 30, 2012)--Hurricane Nadine strengthened somewhat Sunday while churning across the eastern Atlantic far from land, forecasters said.

The U.S. National Hurricane Center in Miami said Nadine was a Category 1 hurricane Sunday with maximum sustained winds of 90 miles per hour.

At 10 a.m. CDT Sunday, Nadine was centered about 640 miles west of the Azores and was moving north-northwest at 9 miles per hour.

Nadine has been swirling around in the Atlantic for more than two weeks since becoming a tropical storm Sept. 11.

No coastal watches or warnings were in effect Sunday.

Forecasters say little change in strength is expected during the day though Nadine should eventually begin gradual weakening.

Hurricane force winds extend out about 30 miles from Nadine's center.