HONOLULU -- The National Weather Service posted a flash flood warning for Windward Oahu until 4:30 pm, and Kauai until 6:45 pm.

The weather service also placed Kauai and Oahu under a flash flood watch until Thursday afternoon.

On Oahu, the flood warning covers an area from Kahaluu through Kahuku to Turtle Bay. The warning also covers Laie, Hauula, Kualoa, Kaaawa, Waikane, Punaluu and Waiahole.

Civil Defense reported a landslide on Johnson Road between Kualoa and Waikane at about 10:45 a.m. Police said the water on Kamehameha Highway was high enough to reach car doors near Kualoa, according to the National Weather Service.

Officials closed Kahuku High School because of the water overflowing the parking lot and creeping up to classrooms.

Forecasters said the water runoff from the rains is expected to cause flash flooding in streams and could trigger more mudslides.

The Punaluu Pump rain gauge reported 5.65 inches of rain between 5 a.m. and 5 p.m. Nearly three and a half inches fell in the three hours between 8 a.m. and 11 a.m. alone. The Kii gauge near Kahuku picked up 1.94 inches in the 12 hour period that ended at 5 p.m.

On Kauai, the flash flood warning covered an area 21 miles west of Lihue, from Kekaha through Waimea to Pakala. Hanapepe and Mana also were included in the warning area.

A weather system west of Hawaii has produced the unsettled conditions. Kauai's weather will be affected by an area of heavy rain to the south of the Garden Isle. On Oahu, the windward side of the Koolau range, especially the area from Kahuku to Kaneohe, will have the highest likelihood of flooding as clouds anchor themselves to the terrain, resulting slow-moving heavy showers over that area.