Last night's thunderstorm over O'ahu and Kaua'i was a treat for those who were awake from 2 a.m. to 5 a.m. The National Weather Service today said more is on the way.

Locally heavy rain and thunderstorms are possible over the next few days, especially tonight and tomorrow.

The weather system was expected to drop one to two inches of rain per hour for several hours today over Kaua'i, with frequent flashes of lightning.

A flash flood flood watch also was to be in effect until 4 p.m. today for O'ahu and Kaua'i.

The source of the rain was an upper level low that had produced a moist, unstable atmosphere.

On O'ahu, the rain was heaviest over Moanalua with .62 inches falling between 2 a.m. and 5 a.m., said Maureen Ballard, today's lead forecaster for the weather service. And over at Aloha Tower, where weather service rain gauges often receive little precipitation, .44 inches of rain fell during the same period, Ballard said.

Multiple lightning strikes on Kaua'i last night knocked out power to communities in various parts of the island. Parts of Koloa were without power for an hour and 45 minutes, with electric service restored at nearly 11 p.m. The Lihu'e and Kapa'a areas had a half-hour outage about 9 p.m.

Kaua'i Island Utility Co-op operations supervisor Carey Koide said the firm identified three major strikes and numerous minor lightning strikes overnight, but that by mid-morning the system was operating properly.

"Everything is back to normal as it stands right now," Koide said.