Oahu remains under a flash flood warning until 8 a.m. Wednesday, as heavy rain continues over the Koolau mountains, the National Weather Service said this morning.

The warning was issued last night and had been due to expire at 5 a.m.

“ At 4:45 a.m., radar and rain gages indicated that moderate to heavy rain continued over the Koolau mountains, with most of the rainfall now remaining over and east of the Koolaus.” forecasters said. The warning includes “Windward communities from Turtle Bay to Kaaawa to Kaneohe, and North Shore communities from Turtle Bay to Pupukea.

“However, with the heavy rain nearly stationary over the Koolaus, all streams emanating from the Koolaus will continue to be at risk of overrunning their banks this morning” forecasters said. Mudslides are also possible.

A warning means flash flooding is imminent or occurring in streams, roads and low-lying areas. The public is advised to move to higher ground and to not cross fast-flowing or rising water in a vehicle or on foot.