A flash flood watch is in effect for Oahu and Kauai County until late Saturday night as a cold front that could bring heavy rain, and perhaps thunderstorms, approaches the islands.

Kauai and Niihau are expected to get the storm’s first hit tonight.

"As a cold front approaches from the west, isolated thunderstorms will develop over Kauai and Niihau tonight," according to the National Weather Service. "Some of these thunderstorms will be capable of producing strong and gusty winds, along with frequent lightning."

The cold front is expected to approach Oahu late tonight, forecasters say.

The cold front is expected to stall near Oahu and wet weather is forecast through Sunday for Oahu, Kauai and Niihau.

Heavy rain, possibly thunderstorms, are expected.

A flash flood watch means that conditions may develop that could lead to flash flooding. Residents are urged to monitor the latest weather forecasts and to be prepared to take action if warnings are issued.

Forecasters are especially worried about the chance of flooding on Kauai because the ground is still saturated from recent rains.

Hazy conditions and light winds are predicted for Monday and Tuesday.