A flash flood advisory and later a flash flood watch had neighbors from Punalu'u to Hau'ula standing vigil yesterday prepared for the worst, but forecasters said conditions should improve by tomorrow even though the weather will remain "unsettled," with the possibility of heavy downpours.

A kona low-pressure area west of Kaua'i brought wet weather to Kaua'i, O'ahu and the Big Island yesterday but few problems were reported. The threat of heavy showers will continue through at least tomorrow, said Tom Birchard of the National Weather Service.

"With a fair amount of certainty, I can say that we're going to remain unsettled through Thursday, and Friday and Saturday will look better, then a weak front on Sunday," Birchard said. "We're still going to be unstable and the potential for heavy rain will be there."

The threat of rain had Windward residents concerned, especially with yesterday's flash flood advisory.

"We're always on needles and pins," said Chris Guerrero, who lives next to Kaipapa'u Stream in Hau'ula. "The first night I was up until 3 o'clock waiting."

Half of the bridge crossing the stream on Kamehameha Highway is clogged with rock and debris, impeding water flow and, during heavy rain, causing water to flood neighboring properties.

Guerrero said the water came over his wall yesterday morning when parts of the Windward Coast received a heavy, but brief, dousing. Fortunately, the water didn't reach his home.

Marianne Vaughan of Punalu'u escaped trouble yesterday, too. But she wasn't so lucky on Sunday. That's when a debris-filled culvert two houses from her home caused water to overflow into her neighbors' yards and down to her lot, entering her home through a screen door.

Still, she said, the situation was worse last year when a historic 40-plus days of rain sent six inches of water flooding into her living room.

Vaughan blames a debris-filled culvert.

"It seems to be an ongoing problem with this culvert because every time we have a good rain, it fills up with branches and leaves," she said.

Firefighters cleared the culvert Sunday night, Vaughan said.

"Now that the bridge is clear and the culvert is empty, we won't have the flooding problem again," she said.

Early yesterday morning, Punalu'u, La'ie and Kahuku were drenched. And in the early afternoon, Mililani, Wahiawa, Hale'iwa and Waialua were soaked, Birchard said. The rain quickly subsided and there were no reports of problems, he said. O'ahu Civil Defense also reported no problems yesterday.

The Big Island had moderate but persistent rain Monday night and early yesterday morning that caused minor problems in Hawaiian Paradise Park, but Big Island Civil Defense said that was because of the poor drainage system, Birchard said.

Reach Eloise Aguiar at eaguiar@honoluluadvertiser.com.