Boards cover the lobby windows of the Hilo Seaside Hotel in anticipation of Hurricane Flossie. Photo by TIM WRIGHT | Associated Press

Hurricane Flossie "is showing definite signs of weakening," the National Weather Service said late tonight, but a hurricane watch and tropical storm warning remained in effect for the Big Island.

"But the weakening trend makes it less likely that Flossie will have a major impact outside the Big Island," the weather service said in its 11 p.m. update.

The hurricane still had maximum sustained winds of 115 mph.

Flossie is expected to deliver tropical storm force winds of 39 mph and as much as 10 inches of rain over parts of the Big Island tomorrow, according to the National Weather Service.

East to southeast winds of 40 to 50 mph with gusts up to 60 mph are likely later tomorrow afternoon as Flossie passes within 100 miles of the Big Island, according to the weather service.

It is expected to pass south of South Point about 3 p.m. tomorrow, the weather service said.

By about 10 p.m. tonight, about 73 Big Island residents had showed up at Red Cross hurricane shelters.

The fullest shelter was Waiakea High, where about 30 people planned to spend the night. About 28 people were at Pahoa High and Intermediate School.

Troy Kindred, administrator for the Hawai'i County Civil Defense Agency, said residents who go to shelters should have a 72-hour emergency kit.

He said they shouldn't assume the shelters will provide food, cots or other essentials.

Flossie's path around the Hawaiian Islands is expected to generate 8 to 12 foot tall surf on southeast facing shores of the Big Island tonight, increasing to 15 to 20 feet tomorrow.

Surf along northeast facing shores of the Big Island are forecast at 5 to 8 feet tonight, increasing to 8 to 12 feet tomorrow.

Heavy showers and thunderstorms may produce 10 inches or more of rainfall in the Ka'u District through tomorrow night. Rainfall of 5 to 10 inches could hit the eastern slopes through tomorrow night, according to the weather service.

At 8 p.m. tonight, Flossie was about 295 miles southeast of Hilo and moving west-northwest at about 16 mph.

It's carrying maximum sustained winds near 120 mph with higher gusts and is not expected to change in strength over the next 24 hours.

Flossie continues to generate hurricane force winds up to 40 miles from its center and tropical storm force winds up to 140 miles.

Big Island Mayor Harry Kim has declared a state of emergency on the Big Island, which is expected to bear the brunt of Flossie's effects.

Both a hurricane watch and a tropical storm warning remain in effect for the Big Island.

A hurricane watch means hurricane conditions were possible within 36 hours. A flash flood watch was also issued for the Big Island through Wednesday, with possible flash flooding in areas.

Forecasters earlier had said cooler weather could weaken the storm to a Category 1 hurricane, with sustained wind of at least 74 mph.

"The intensity has remained stronger than what was originally forecast, but the track has been pretty much right on," said Jim Weyman, the weather service's meteorologist in charge in Honolulu.

The Big Island is largely rural, with about 150,000 people, and most live in the west or northeast, not the southern portion expected to be hit hardest by the hurricane. Other islands are expected to get much less of the storm's wind and rain.

Meteorologists cautioned that even a slight change of course in the unpredictable storm could take it closer to land.

Track the hurricane's path on the National Oceanic and Atmospheric Administration site at Flossie forecast.

"Everyone in the Hawaiian Islands is urged to continue monitoring the progress of Hurricane Flossie," the Central Pacific Hurricane Center said in a statement. "A northward shift in the track could potentially bring hurricane conditions to the Big Island."

Emergency workers mobilized yesterday to prepare, Kim said. "You always prepare for the worst-case scenario and hope for the best," he said.

Four Air Force WC-130 hurricane tracker planes were dispatched from Mississippi and flew into the storm to gather measurements yesterday afternoon, said Roy Matsuda, lead forecaster at the Honolulu office of the National Weather Service.

"The weakening process looks much slower. It will keep more of its juice," Matsuda said. "It won't be a tropical storm. It'll be a weak or minimal hurricane."