(Adds concerned resident, paragraphs 9-11)
By Malia Mattoch McManus
HONOLULU, Aug 5 (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 may 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 hurricane center said in an advisory.
Residents stocked up on basics as authorities in Honolulu advised them to prepare a seven-day disaster supply kit. The hurricane was expected to turn west-northwest later on Tuesday and Wednesday, the National Hurricane Center 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).
Shoppers in Honolulu waited in line at supermarkets with carts full of bottled water, batteries and nonperishable food items.
"With Hawaii's remoteness, it could be as long as a week before a full disaster relief operation can be initiated," the department said in a statement late on Monday.
Honolulu school teacher Gina Nakahodo said she had felt calm about the situation, until she reached the empty water aisle of her local grocery store early on Tuesday.
"We've had so many storms that have passed us by, but with these two back to back you begin to worry. Then all of the sudden the aisles are empty and there's no water and it makes your heart pound a little," Nakahodo said.
She said she talked to a couple visiting from California, and told them everything was going to be OK. "But in the back of my mind I'm wondering, 'what's going to happen?'," she said.
Hurricanes rarely hit Hawaii. The state was washed over by Hurricane Flossie in 2007, which caused 20-foot (6-meter) waves but very little damage. Hurricane Neki did minor damage to a marine national monument northwest of the islands in 2009.
In 1992, Hurricane Iniki pummeled the island of Kauai, killing six people and causing estimated damages of $2.4 billion. Before that, the last recorded hurricane to hit Hawaii was the Kohala Cyclone in 1871.
Separately on Tuesday, the NHC said Bertha, the second hurricane of the 2014 Atlantic season, had weakened to a tropical storm some 475 miles (765 km) west of Bermuda. (Additional reporting and writing by Daniel Wallis; Editing by Cynthia Johnston and Sandra Maler)