The National Weather Service has issued a flood advisory for Oahu until 3 a.m. because of persistent moderate to heavy showers over the Koolaus.
Radar showed the rain falling upslope of Windward Oahu communities from Hauula to Kaneohe.
In addition, rain gages on Waikane and Kahana streams reported elevated levels.
Other locations in the advisory include Punaluu, Kaawa, Kahaluu and Waiahole.
Forecasters advise residents to stay away from streams, drainage ditches and low-lying areas prone to flooding.
Rainfall and runoff will also cause hazardous driving conditions due to water on the roads, reduced visibility and poor braking conditions.
Do not cross fast-flowing or rising waters in vehicles or on foot.