WASHINGTON, Sept. 6 (Xinhua) -- Florence has weakened slightly to a Category 3 hurricane but should remain a powerful storm for several more days, the U.S. National Hurricane Center (NHC) said late Wednesday.

The hurricane was located about 1,990 km east-southeast of Bermuda and 1,750 km east-northeast of the northern Leeward Islands, with maximum sustained winds of 205 km per hour, according to the Miami-based weather agency.

Some gradual weakening is forecast during the next 48 hours, with restrengthening possible over the weekend, it added.

There are no coastal watches or warnings in effect.

Florence, the first major hurricane of the Atlantic season, was upgraded to a Category 4 hurricane earlier in the day, with maximum sustained winds of 215 km per hour.

Florence is the basin's sixth named storm of the year.

Forecasters have said the Atlantic hurricane season is now expected to be less active as it enters its peak months due to a combination of conditions in the ocean and atmosphere that helps to limit storm development.

They are expecting nine to 13 named storms with winds of 62 km per hour or higher, of which four to seven will strengthen into hurricanes.

Of those storms, there may be up to two major hurricanes, which are classified as Category 3, 4 and 5 with winds of 177 km per hour or higher.

Tropical Storm Gordon has weakened into a tropical depression over the U.S. state of Mississippi after making landfall late Tuesday near the Alabama-Mississippi border with near-hurricane level winds, killing a two-year-old child when a tree fell on her family's mobile home in Pensacola, Florida.

By Wednesday afternoon, Gordon's center was well inland, dumping heavy rains and causing flooding in western Florida and coastal Alabama, the NHC said.