HONOLULU (AP) -- A tropical storm making its way toward Hawaii had residents of Maui and the Big Island on Monday bracing for possible flooding, 60 mph wind gusts and waves that could reach as high as 18 feet.
Tropical Storm Flossie could also bring mudslides, tornadoes and waterspouts, forecasters said.
"For the folks on the Big Island and Maui, if you're preparing your home, you should be rushing those preparations to completion," said Michael Cantin, a warning coordination meteorologist with the National Weather Service in Honolulu.
The service on Sunday issued a tropical storm warning for Oahu, Hawaii's most populous island with the city of Honolulu, to go along with previous warnings for the Big Island, Maui, Molokai and Lanai. The warning means the storm represents a threat to life and property.
The service previously issued only a watch for Kauai and Niihau. But it upgraded that to a warning and said a small change in Flossie's track could result in higher winds on the islands.
Hawaii Gov. Neil Abercrombie signed an emergency proclamation in anticipation of the storm, allowing the state to use its disaster fund to pay for staff overtime, supplies and other resources. The proclamation also allows the state to call Hawaii National Guard members to duty, if necessary.
Although the storm had weakened somewhat by Monday, the weather service warned that it could remain a threat through Wednesday.
The storm was packing sustained winds of 50 mph and was centered 200 miles east of Hilo early Monday. Television footage aired on Hawaii News Now from Maui showed high surf breaking on rocks near Hana at around 7 a.m. local time. Forecasters also reported dangerous waves hitting the eastern shores of the Big Island.
Cantin said wind gusts likely will be able to knock down power poles and blow away loose objects. He said people should be careful of trying to walk or drive across water if floods happen.
"It takes about 6 inches of water to knock you off your feet ... 12 inches to move a vehicle," he said.
Officials warned people to cancel beach trips, finish necessary storm preparations and evacuate if asked by local officials.
The U.S. Coast Guard has closed three ports — two on the Big Island where the storm was expected first and a third port on Maui. College campuses and courts were also to be closed Monday on the Big Island. Maui County Civil Defense said shelters would be opening at 9 a.m.
Mike McCartney, chief executive of the Hawaii Tourism Authority, said some airlines have begun to adjust flights and visitors should double-check plans. Airports statewide were open Monday but many flights were being canceled.
Trails and campgrounds were closed on the Big Island, where state officials warned people to avoid forest areas until Flossie clears.
It's not immediately clear which island faces the most danger, though the Big Island — the easternmost island in the archipelago — was likely the first in Flossie's path. Flossie's center was expected to pass near the Big Island and Maui on Monday morning and then south of Oahu several hours later on Monday evening into Tuesday morning.
The storm is expected to drop 6 inches to 10 inches of rain, with higher amounts on the eastern side and less on the western side of islands.
Oskar Garcia can be reached on Twitter at https://twitter.com/oskargarcia
Associated Press writer Christopher Weber in Los Angeles contributed to this report.