MIAMI —  Hurricane Bertha has strengthened to a Category 3 storm.

The Atlantic season's first hurricane is still far from land, but the National Hurricane Center says it now has maximum sustained winds of 115 miles an hour.

The center of the storm is located about 730 miles east-northeast of the Northern Leeward Islands and about 1,150 miles southeast of Bermuda.

Forecasters say it's moving west-northwest at about 12 miles an hour.

Tropical Storm Bertha is approaching warmer waters and is likely to strengthen during the next couple of days.

At 5 a.m. Eastern time today, Bertha was centered about 1,310 miles east of the northern Leeward Islands in the Caribbean.

The first named storm of the Atlantic Hurricane season, Arthur, formed the day before the season officially started June 1 and soaked the Yucatan Peninsula.