Update: 8 a.m.

A flash flood watch continues for Oahu and Kauai County through late tonight.

“The flash flood threat from moderate to heavy showers will increase over the western islands, especially near Kauai,” the National Weather Service said in a bulletin. “These conditions may continue into Friday.”

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A flash flood watch has been issued for Kauai, Oahu and Niihau, effective from this evening through late Thursday night.

The National Weather Service reports that a deep upper-level trough will slowly approach from the northwest during the next few days.

“The atmosphere will gradually moisten today across the western end of the island chain, and by tonight, the threat of heavy showers will increase, especially near Kauai,” weather officials said.

The highest chances for rainfall are along windward slopes, although heavy showers could develop anywhere from Kauai to Oahu, with conditions possibly continuing into Friday.

A wind advisory for the summits of Hawaii island also remains in effect until 6 p.m. today. Elevated, southwest winds will, however, continue into the weekend. Motorists are urged to drive with extreme caution.