(Reuters) - A hurricane and a tropical storm are heading west across the Pacific Ocean toward the tourist haven of Hawaii and the U.S. National Hurricane Center said parts of the islands might need to post watches later on Tuesday.

Hurricane Iselle was about 1,055 miles (1,700 km) east-southeast of Hawaii, moving west at 9 miles per hour (15 km per hour) with maximum sustained winds of 125 mph (200 kph), the National Hurricane Center said.

"Watches may be required for portions of the islands by later today or early Wednesday," the Miami-based weather forecaster said in an advisory.

The hurricane was expected to turn west-northwest later on Tuesday and Wednesday, it said, but was forecast to weaken over the next 48 hours.

Further east over the Pacific, Tropical Storm Julio was about 1,145 miles (1,845 km) from Baja California in Mexico and also expected to continue moving west-northwest through Thursday, the NHC said.

That storm was moving at 13 mph (20 kph) and has maximum sustained wind speeds of 60 mph (95 kph).

The Central Pacific Hurricane Center in Honolulu will issue any further advisories, watches or warnings, it said.

Separately on Tuesday the center said Bertha, the second hurricane of the 2014 Atlantic season, had weakened to a tropical storm some 475 miles (765 km) west of Bermuda.


(Writing by Daniel Wallis; Editing by Cynthia Johnston and Bill Trott)