Oahu and the rest of the state are under a flash flood watch through Sunday because of the potential for heavy rain.

National Weather Service forecaster John Bravender said heavy rain fell Friday on Hawaii island, with Kalapana receiving 5.6 inches in a 24-hour period ending at 8 a.m., and Pahoa 2.6 inches of rainfall in 24 hours ending at 2 p.m.

A weather system is destabilizing the atmosphere and enhancing the usual tradewind showers with the threat of heavy rain and thunderstorms likely through today, the Weather Service said.

On Friday night the weather was expected to be mostly cloudy with numerous showers and isolated thunderstorms in windward and mauka areas.

Today and Sunday, the weather is expected to be mostly cloudy, with windward and mauka areas experiencing numerous showers and a slight chance of thunderstorms. The rain will eventually subside with occasional showers.

Scattered showers with a slight chance of thunderstorms are expected in leeward areas during the day, along with possibly heavy rainfall. The high temperatures will range from 78 to 84, and lows, 68 to 74, with winds 10 to 20 mph and gusty.

For Monday and Tuesday the weather is expected to be mostly cloudy, with occasional showers in the windward and mauka areas and scattered showers in leeward areas. The high temperatures will range from 78 to 83, and lows, 69 to 74, with wind 15 to 20 mph.

The high at Honolulu Airport was 86 degrees on Thursday, and Friday morning’s low was 75.

Hawaii News Now video: Flash flood warning in effect for Maui; rest of Hawaii under flood watch