(Updates)

MIAMI, Sept 29, (Reuters) - Tropical Storm Melissa formed in the Atlantic Ocean on Saturday but posed no threat to land, while Tropical Depression Karen was falling apart, the National Hurricane Center said.

At 5 p.m. (2100 GMT), Melissa, the 13th named Atlantic storm this year, was about 365 miles (590 km) west of the Cape Verde Islands with top sustained winds near 40 mph (65 kph). It was moving toward the northwest at 13 mph (20 kph) and was no threat to land, the Miami-based hurricane center said.

Tropical Depression Karen was 495 miles (795 km) east of the Leeward Islands with winds near 35 mph (55 kph). It was moving toward the northwest.

"This motion should continue until dissipation later tonight," the center said in what it added was its final advisory on Karen.

The 2007 Atlantic storm season, which runs through Nov. 30, has produced four hurricanes, including Lorenzo, which crashed into Mexico's Gulf coast on Friday and killed three people.

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