UPDATE: 10 p.m.

A flash flood warning expired tonight but a flash flood watch remains in effect for Kauai and Niihau through 6 a.m. Wednesday.

Abundant moisture a low-level trough will move westward over Kauai tonight, bringing the potential for additional heavy rain. The National Weather Service said flood-prone roads and other low-lying areas could close due to elevated runoff and overflowing streams.

7 p.m.

The flash flood warning for Kauai has been extended to 10:15 tonight.

Kuhio Highway in Hanalei remains closed as flood waters continue to cover the road. The National Weather Service said most of the mountain rainfall has eased but runoff will be slow to subside.

Both Kauai and Niihau are under a flash flood watch through late tonight. Abundant moisture a low-level trough will move westward over Kauai tonight, bringing the potential for additional heavy rain. NWS said flood-prone roads and other low-lying areas could close due to elevated runoff and overflowing streams.

1:20 p.m.

A flash flood warning has been posted for the island of Kauai due to heavy rain.

The flash flood warning is posted through 4:15 p.m.

At 1:18 p.m., the Hanalei River gauge showed a rapid rise in water level, the National Weather Service said. Flooding is occurring near the bridge and other nearby drainages.

Some locations that will experience flash flooding include Hanalei, Princeville, Kilauea, Omao, Wainiha, Wailua, Kokee State Park, Haena, Koloa, Na Pali State Park, Moloaa and Anahola.

11 a.m.

The National Weather Service has issued a flood advisory for the island of Kauai, effective through 2 p.m. today.

At 10:55 a.m., radar indicated heavy rain moving into the eastern half of Kauai. Rain was falling at a rate of 1 to 3 inches per hour.

Locations in the advisory include, but are not limited to Lihue, Kapaa, Kalaheo, Princeville, Kilauea, Hanalei, Wainiha, Wailua, Haena, Koloa, Na Pali State Park, Moloaa, Anahola and Poipu.

A special marine warning has also been issued for Kauai Channel and leeward, northwest and windward waters of Kauai, due to a line of heavy showers with embedded thunderstorms approaching from the east, effective through 12:30 p.m. today. Wind gusts of 40 knots are expected.

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A high surf advisory remains for the north and west shores of all isles due to continued large and rough surf this morning while a flash flood watch remains in effect for Kauai County and Oahu through this evening.

The National Weather Service issued the high surf advisory for the north and west shores of isles from Kauai to Hawaii island and the north shores of Maui this morning, shortly after a high surf warning for smaller isles expired.

The advisory remains in effect through 6 a.m. Wednesday.

Surf of 10 to 15 feet is expected along north shores, and 5 to 8 feet along west shores. Surf is expected to gradually diminish through tonight.

Wet and windy weather, meanwhile is expected to continue over Kauai County and Oahu through this afternoon, prompting a flash flood watch for those areas through 6 p.m. today.

Forecasters said a low-level trough moving west from Maui will bring a large band of showers that will combine forces with strong, gusty winds, bringing possible thunderstorms.

The highest rainfall rates are expected in the windward and mauka areas, and officials warn of elevated runoff on flood-prone roads and overflowing streams.

A wind advisory has also been issued for Niihau and Kauai through 6 p.m. today due to northeast winds of 20 to 30 mph, with gusts up to 50 mph.

Elsewhere, weather trends are expected to improve, including on Hawaii island, where a flash flood watch was canceled. Rainfall amounts are also expected to decrease over Maui by this afternoon, where a wind advisory was also canceled due to more moderate trades, forecasters said.

A winter weather advisory remains in effect for Hawaii island summits through 6 p.m. today because forecasters expect 1 to 2 more inches of snow to fall with the arrival of patchy, freezing fog this evening.

Forecasters said trades will lower to the moderate to breezy range on Wednesday, bringing periods of windward and mauka area showers, before ramping up again this weekend.

A small craft advisory also remains in effect from northwest of Kauai to windward of Hawaii island through 6 p.m. today.