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Oahu was drying out after moisture from what’s left of Tropical Storm Wali dumped rain at rates of 4 inches and hour or more on much of the island Saturday night and Sunday morning.

On Maui, the National Weather Service extended a flood advisory Sunday after radar continued to show heavy rain over windward west Maui and windward Haleakala. Other locations in the advisory include Waihee, Kahului, Makawao, Hookipa Beach Park and Haiku. The advisory was in effect until 12:15 a.m.

On Hawaii island, rain gauges at Waiakea Uka showed rain of more than one inch and hour falling at 7:54 p.m. Sunday, prompting a flood advisory until 11 p.m. More heavy rain fell at Piihonua, Glenwood and windward Big Island locations.

Also on the Big Island, a lightning strike damaged equipment at the Hawaiian Volcano Observatory at 9:30 p.m. Saturday, the weather service said. Kauai County also closed the Kekaha landfill Sunday afternoon because of lightning.

Forecasters cautioned sunny Sunday skies on Oahu could be just a break in the weather and conditions remain ripe for more heavy rain and even thunderstorms.

The entire state remains under a flash flood watch until 6 p.m. Monday.

"It’s not over yet," said John Cummings, a spokesman for Honolulu’s Emergency Management Department.

"We have a lot of moisture in the ground and if we get a lot of rain it could compound the situation and we could have more flooding," he said. "Until the system is completely out of our area, it’s still a hazardous situation."

Honolulu police closed the roadway at 53-309 Kamehameha Highway, near the Kaneohe side of Punaluu Beach Park, due to flooding before 1:45 a.m. Police also closed Kamehameha Highway at Waikane after eight cars stalled on the flooded roadway, the weather service said.

Crews cleared one lane of Kamehameha Highway in the morning and contra-flowed traffic until the highway was completely opened before 4 p.m.

Kapaa Quarry Road at Kalanianaole Highway was closed just before 4 a.m. and reopened around 8 a.m.

Several homes were also flooded in Hauula and Punaluu and the storm took down large trees in Kahana.

Cummings said no major property damage was reported overnight and there were no rescues on Oahu.

In the 24-hour period ending at 8 a.m., more than 13 inches of rain fell on Kahana Stream, the Oahu Forest National Wildlife Reserve, Hakipuu Mauka, and Punaluu Stream in Windward Oahu. About a foot of rain fell at the Poamoho and Punaluu Pump rain gauges.

On Saturday, thunderstorms and localized heavy rain on the Big Island dropped up to 2 inches of rain an hour Saturday over Glenwood and Pohakuloa.

The interactions between a weather system northwest of the islands and the increased moisture from Wali’s remnants are creating conditions that will generate heavy rain and more possible thunderstorms for the next couple of days, forecasters said.

"Shower activity will increase and decrease with time, but locally heavy rain will remain possible in most areas through about Monday," forecasters said.

The state forecast for Sunday night and Monday calls for rain in windward and mauka areas on Maui and Oahu and scattered showers elsewhere. Thunderstorms are also possible.

The forecast for Honolulu and southern shores of Oahu calls for a 50 percent chance of rain Sunday night and Monday and a 70 percent chance of rainTuesday.

A gradual return to more typical trade wind weather is expected by Wednesday, but more tropical moisture and rain may move over the islands later in the week.