Hurricane Joaquin strengthens to 'dangerous Category 4 hurricane', forecast to approach East Coast by weekend _lowres

Forecasters say Hurricane Joaquin has strengthened to "an extremely dangerous Category 4 hurricane." (Photo from National Hurricane Center)

MIAMI (AP) — Forecasters say Hurricane Joaquin has strengthened to "an extremely dangerous Category 4 hurricane."

The National Hurricane Center in Miami said Thursday afternoon that additional strengthening is expected over the next 24 hours, as the storm moves past the Bahamas, bringing winds, heavy rain, dangerous surf and significant storm surge.

The storm has maximum sustained winds of 130 mph (210 kph) and is moving southwest at 6 mph (9 kph). It is about 70 miles (115 kilometers) south-southeast of San Salvador, Bahamas.

A hurricane watch is in effect for much of the Bahamas and other nearby islands. Forecasters say the center of Joaquin should move over or near portions of the central Bahamas Thursday afternoon and night.

Forecast maps show the storm passing the Bahamas and then making its way toward the U.S. over the next couple of days.