Tropical Depression Kenneth has run out of steam, but moisture the former hurricane dragged into the Islands, combined with rain from another weather system, could cause heavy rains statewide, according to the National Weather Service in Honolulu.

The state remains under a flash-flood watch through tomorrow afternoon, said Pete Donaldson, a forecaster with the weather service.

In anticipation, the state Department of Health issued a statewide "brown water" advisory.

"The public is advised to stay out of coastal waters impacted by storm water runoff that may contain debris and possible sewage and chemical contamination," said Watson Okubo, supervisor for the Clean Water Monitoring Section of the Department of Health.

"Streams may overflow their banks and flooding may result. The public should stay out of all flood waters due to possible sewage, chemical and leptospirosis contamination."

The threat of heavy rain also has postponed this weekend's Sunset on the Plains celebration at Kapolei. It was rescheduled for next weekend.

Forecasters said it's a combination of moisture from Kenneth and increased instability from an upper level, cold, low-pressure center that's causing increasing showers over the main Hawaiian Islands.

A flash-flood watch means flooding is possible but not imminent. Civil Defense and emergency officials are advising residents to take precautions.

On the Big Island, Civil Defense, police and fire officials met with Mayor Harry Kim Thursday to discuss strategies and preparedness.

"Everyone needs to be prepared," said Lanny Nakano, acting administrator for Hawai'i County Civil Defense. "If you have had problems with flooding in the past, you need to be ready."

O'ahu Civil Defense urged residents in flood-prone areas to store sandbags, plywood, plastic sheeting and lumber to protect property.

The National Weather Service reported the heaviest rains on the Big Island were in Glenwood, upper Puna, with 3.87 inches falling in the 24 hours ending at 2 p.m. yesterday. Waiakea Uka, mauka of Hilo, got 2.65 inches of rainfall, and Honoka'a got 1.76 inches.

The storm caused few problems yesterday.

Honoli'i Beach Park near Hilo was closed from noon until about 2:30 p.m. because heavy flows from Honoli'i Stream created a dangerous current in the bay, but there were no road closures because of flooding and no reports of significant damage, said Nakano.

"It looks like we got off easy here," Nakano said late yesterday afternoon.

There was little rainfall on the leeward side of the Big Island. However, Nakano said, there was a report of a cyclone-like wind in the Kawaihae area that damaged a roof, and Hapuna State Park was closed briefly because of wind gusts of up to 50 mph.

The hurricane season runs through Nov. 30.

The Associated Press contributed to this report.

Reach Karen Blakeman at kblakeman@honoluluadvertiser.com and Kevin Dayton at kdayton@honoluluadvertiser.com.