Rain continued to fall over much of the state yesterday, and the wet weather is expected to continue through the weekend, forecasters said.

On O'ahu, heavy rain caused a sewage spill in Nu'uanu and turned H-1 Freeway near Makakilo into a lake.

There were several unconfirmed reports of funnel clouds spotted off Kalaeloa yesterday afternoon, the National Weather Service said.

Showers will continue through the weekend, with rain in windward areas, as the weather system returns to normal, meteorologist Ian Morrison said yesterday. The storms will diminish in leeward areas and weather conditions should be more stable by Sunday, he said.

The weather service issued a flood advisory for O'ahu last night and flash-flood watches for Maui and the Big Island. Moloka'i remained under a flash-flood warning until 9:45 p.m. yesterday.

Yesterday afternoon, heavy rain washed mud onto the westbound lanes of H-1 Freeway between the 'Ewa and Makakilo offramps, backing up traffic.

The water rushed over a construction site where workers are building a new freeway interchange, through fences erected to prevent erosion, over a 3-foot-high concrete barrier and onto the road, said Scott Ishikawa, state Department of Transportation spokesperson.

"We were basically in a stream of red dirt water," said motorist Theresa Kuehu, who was returning to her home in Nanakuli at about 2:45 p.m. when she nearly drove into a river of muddy water several feet deep.

To avoid the water, vehicles drove single-file in the left shoulder lane, she said. It was pouring and traffic was moving at a walking pace or slower, she said.

Highway crews cleared the mud and debris and the freeway lanes were reopened before 5 p.m.

Ishikawa said workers saw that the water came from above the construction site and that there was not much they could do to stop it. The rain was so heavy that a drainage culvert was three-quarters full in less than two hours, he said.

"I don't think anything we put out there could have stopped (the water)," Ishikawa said.

The westbound lanes were cleared of mud and debris and reopened shortly after, but an inspector remained at the site to monitor the situation, he said.

On Wednesday night, 2,300 gallons of sewage spilled over from a manhole at 3255 Nu'uanu Ave. About 700 gallons of the sewage flowed into Nu'uanu Stream, while the remaining 1,600 gallons percolated into the ground, the state Department of Health's Clean Water Branch said yesterday.

People are advised to stay out of Nu'uanu Stream until water tests show bacteria levels have returned to normal.