(Reuters) - Hurricane Lane strengthened to a major Category 4 storm on Tuesday and was expected later this week to threaten Hawaii with strong winds, flash flooding and pounding surf, authorities said.
Lane's winds rose to 155 mph (249 kmh) as it moved westward at 9 mph and was expected to turn toward the Hawaiian archipelago on Wednesday, the National Hurricane Center said in an advisory.
The storm was located about 400 miles (644 km) south-southeast of Hilo on the island of Hawaii, known as the Big Island.
"Lane is forecast to pass near the Hawaiian Islands this week, potentially bringing dangerously strong winds, rough seas and large swells," the National Weather Service said in a statement.
The Big Island as well as Maui, Lanai and Moloka'i were under hurricane and flash flood watches, according to the National Weather Service.
(Reporting by Andrew Hay, editing by G Crosse)