Heavy rains over windward areas prompted the National Weather Service to issue a flash flood warning for Oahu early Sunday morning.

Radar showed rain falling at rates of more than 2 inches per hour along Windward Oahu from Hauula to Kaneohe at 11:41 p.m. Saturday, forecasters said.

Punaluu stream and Kahana stream were seeing rapid rises in stream levels.

Other locations in the warning include Punaluu, Waikane and Kaawa.

The warning was in effect until 2:45 a.m.

Lightning could be seen over East Oahu early Sunday morning. Forecasters said more thunderstorms are possible through Sunday night..

“It’s important to note that thunderstorms will be stronger than they were today (Saturday) and will be capable of producing frequent lightning,” forecasters said in a weather advisory.

The weather system northwest of Kauai that is causing the wet conditions on the western end of the state should move away by Monday night, allowing cooling tradewinds to return.

But the atmosphere remains wet and unstable, so windward and mauka showers are expected. Some of the rain may also move over leeward areas.