Miami ? Tropical Storm Debby weakened off the coast of the Cape Verde islands in the eastern Atlantic on Wednesday and posed no immediate threat to land, forecasters said.

At 4 p.m. CDT, the storm’s top sustained winds had slowed to about 45 mph from about 50 mph earlier in the day, well below the 74 mph threshold for a hurricane. Slow strengthening was forecast for today.

The fourth named storm of the 2006 Atlantic hurricane season was centered about 610 miles west-northwest of the Cape Verde islands, which are about 350 miles off the African coast. Debby was moving northwest at about 20 mph, the National Hurricane Center said.