Tropical Storm Flossie should bring little rain but lots of gusty wind to O'ahu tonight as it comes within 180 miles south of the island.

Flossie was on a course to pass O'ahu at 7 p.m. today, but National Weather forecaster Tom Birchard said yesterday that the storm's changing speed and course could delay its swing by O'ahu.

Last night, Flossie was downgraded to a tropical storm from a Category 1 hurricane.

Forecasters issued high-surf advisories, with waves of up to 8 feet possible for east- and south-facing shores throughout today.

"Not a whole lot of rain is expected — 1 to 2 inches for the Windward side, maybe even less for the Leeward side, which is not great news to those firefighters," Birchard said.

Firefighters have been receiving spot weather forecasts from the National Weather Service as they fight a stubborn 5,000-acre brushfire outside Waialua.

"The winds are definitely creating a problem for the Fire Department," Birchard said.

Flossie is expected to generate easterly winds of 20 to 30 mph and gusts up to 40 mph on O'ahu. Yesterday's gusts neared a higher-than-normal 40 mph on O'ahu, Birchard said.

The winds and gusts are caused by a persistent high-pressure system that's been sitting north of the Islands all summer and the low-pressure system surrounding Flossie, Birchard said.

"Between the two, it's like you've narrowed the gap that the air can flow through, giving us strong east winds on all of the islands," Birchard said. "On O'ahu, it creates stronger wind gusts along the Ko'olau range."

Hot, dry winds yesterday led University of Hawai'i officials to close hiking trails at Lyon Arboretum after tree limbs and pieces of a greenhouse roof were blown down.

The state Department of Land and Natural Resources also closed the popular Kuaokala and Mokule'ia forest reserves, Peacock Flats Campground and Kealia Trail on O'ahu's North Shore because of the dual threats of the nearby brushfire and Flossie.

"There is the potential danger to hikers, hunters and campers who may be up in that area," said DLNR spokeswoman Deborah Ward. "It's a public safety issue due to the wildfire. With consideration for the potential impact of Flossie on O'ahu, that's another reason for closing."

At the City Mill store on Nimitz Highway, shoppers on Monday and yesterday filled the aisles as if it were a busy weekend, said manager Watson Tanuvasa.

"Mondays are usually slow," Tanuvasa said. "But it was like, wow — a normal weekend."

City Mill employees stocked three different wind-up radios that were selling quickly, along with flashlights and batteries, Tanuvasa said.

"We just put them out (Monday) night but they've been moving steadily," Tanuvasa said.

The Pearl City Wal-Mart also has had unusually high traffic but has been able to keep its shelves filled with bottled water, batteries and flashlights, said manager Kini Santana.

"We've been very steady," Santana said. "There are a lot more customers and a lot more customers who are aware of the events that are going on."

Reach Dan Nakaso at dnakaso@honoluluadvertiser.com.