KANE'OHE — Lani Chase didn't need today's forecast to know what the future may hold for her Hau'ula Homestead Road home and neighborhood. All she had to do was look at the flooded streets outside her house yesterday to know it was time to get ready for another round of potential flooding today.

"I love the rain, but this is getting old," Chase said. "I'm walking outside and we're already flooding. It's 3 inches deep, and it just started an hour ago. And this may just be runoff."

Parts of Windward O'ahu, along with some parts of Neighbor Islands, got an early dose yesterday of the heavy rains expected to douse Hawai'i over the next two days. The National Weather Service has issued a flash flood watch for all islands until late tomorrow night, and said yesterday that at about 3:55 p.m., it received two reports of a large waterspout north of the Marine base on Kane'ohe Bay. The waterspout lasted about 10 minutes and was about 100 yards long, but did not cause any damage, said forecaster Robert Ballard.

The sighting led the weather service to issue a warning to boaters of the potential hazard.

"That's a sizable waterspout. It was from a severe thunderstorm that was east of O'ahu," Ballard said. "Those can definitely do damage to water craft. Anytime we have these kind of strong to severe thunderstorms out over the water, it's a very dangerous situation because waterspouts can form from them with little warning."

Kevin Kodama, a hydrologist for the weather service, said the developing storm system moving in from the southwest is expected to arrive tomorrow. Conditions should remain somewhat unstable into the weekend, he said, but the rain won't be as bad as today's and tomorrow's, Kodama said. The extended forecast calls for trade winds returning by the middle of next week, he said.

"It might be wet trades, which is better than this deep instability, this deep convection of the last four weeks," Kodama said.

In the meantime, Islanders are gearing up for another battle with Mother Nature. Chase said sandbags are in place to divert the flow of water near her house. Other residents are doing the same.

"I'm just going to get my kids," she said. "We try to get everything in order so if something happens, the kids will be fed, and if the electricity goes out, we're prepared for that, too."

A Hau'ula resident for 10 years, Chase said the stream had never overflowed in the past decade, but in the past three weeks, it has jumped its bank three times, and if volunteers and donors hadn't given her family a hand with the sandbags, her family would be facing devastation.

"We are so grateful for the help we got," she said, choking back tears. "It really touches my heart that people reached out to help us."

City and state crews were out yesterday clearing debris left by Sunday's storm. Scott Ishikawa, spokesman for the state Department of Transportation, said crews were at the Wilson Tunnel and on Kamehameha Highway in Kahalu'u, clearing two sites there.

"It's becoming a routine," Ishikawa said. "After each storm, we're going out and clearing everything we can. It's like an endless cycle at this point."

Mitchell Balutski, of Ka'a'awa, said the military cleared the stream next to his home and that it's ready for the next onslaught, but all that could change if a landslide dumps more trees, mud and bushes into the water. Balutski said he'll keep an eye on conditions because a huge chunk of land that fronted his property washed away during one of the storms that hit in the last four weeks. The debris could clog the bridge, flooding the highway, but he's not worried about the stream, he said.

Balutski said he's more concerned about his neighbor's property and people taking chances with the weather.

"We don't control the elements," he said. "We just control our attitude toward the elements. Enjoy, take precautions and look out for those hazards. No let things happen that people will regret."

Reach Eloise Aguiar at eaguiar@honoluluadvertiser.com.