NHC upgrades Ernesto to a Category 1 hurricane

(NBC, KYMA/KECY) - The National Hurricane Center (NHC) says Ernesto has strengthened into a Category 1 hurricane.

The upgrade was announced Wednesday morning as the storm dumped torrential rain on Puerto Rico, knocking out power to about half of the U.S. territory.

The storm was located about 175 miles northwest of San Juan, Puerto Rico and was moving out over open waters.

It had maximum sustained winds of 75 mph and was moving northwest at 16 mph.

A tropical storm warning was in effect for Puerto Rico and its outlying islands and for the U.S. and British Virgin Islands, where island-wide blackouts are already being reported in St. John and Dt. Croix.

At least six cellphone towers have already been knocked off-line across the U.S. territory, according to officials.

Ernesto is expected to become a major Category 3 storm in the coming days and then weaken slightly to a Category 2 as it nears Bermuda on Friday and Saturday.

Between four-to-six inches of rain is expected in the U.S. and British Virgin Islands and between six-to-eight inches in Puerto Rico, with up to 10 inches in isolated areas.

Ernesto is the fifth named storm of this year's Atlantic hurricane season.