The National Weather Service issued flash-flood and high-wind watches just before 4 a.m. for Kaua'i, O'ahu, Moloka'i, Lana'i and Maui. They will remain in effect through tomorrow.

Heavy rainfall, which is associated with a cold front, is expected to move south through the state until Saturday when a low-pressure system aloft will bring more rain and isolated thundershowers.

The weather service cautioned residents near steep ridges to watch for rock and mud slides. But because the rain will come in surges, run-off may be limited.

"If you get heavy rain for several days in a row, that is when you get these mudslides," said lead forecaster Bob Farrell. "It wouldn’t happen until later on, maybe over the weekend."

Southerly winds of 15 to 30 mph with gusts up to 50 mph are still forecast. The strongest winds are expected during the early hours of the storm.

As a general rule, winds are strongest in downslope areas. Kailua and Kane'ohe residents could experience damaging winds, the weather service said.

But even with the warnings, some Kaua'i residents were looking skyward about mid-morning and wondering.

"It was dumping early this morning about 7 but it’s nice and blue now," said Kaua'i County fire Capt. Gordon Tamura who works at the Waimea fire station.

He knew more was on the way.

"It was a quick and heavy downpour and it moved off," he said. "It was just the teaser."