The National Weather Service in Honolulu has issued a high surf warning for north- and east-facing shores of the island through Thursday morning. Surf heights of 25-35 feet are possible on north-facing shores with surf of 15-20 feet on east-facing shores. The swell will primarily hit the Hamakua Coast with other areas in Hilo feeling the impact.
Surf is expected to peak Wednesday and diminish Thursday.
A flash flood watch has also been issued for the Big Island through Thursday afternoon.
A flash flood watch means conditions may develop that lead to flash flooding.
Abundant moisture moving over the islands from the east will combine with a developing upper level trough to bring the threat of widespread moderate to heavy rain and isolated thunderstorms, according to the service. The area of heavy rain is expected to begin moving over the island tonight and gradually shift westward.
Forecasters said the rain will be widespread and slow-moving affecting areas in the lower elevations.
Heavy rain is also expected over the higher elevations and will likely produce flash flooding.