(BIVN) – The National Weather Service in Honolulu has issued a High Surf Warning for the State of Hawaiʻi, as a “short lived large long period northeast (40 degrees) swell builds through the island chain late tonight.”

North- and east-facing shores on the Island of Hawaiʻi are included in the warning, as surf heights of 14 to 18 feet are expected overnight and into Monday morning. Forecasters say impacts could be “very high.”

“Expect ocean water surging and sweeping across beaches, coastal benches, and lava flows creating the potential for impacts to coastal properties and infrastructure, including roadways,” the National Weather Service stated. “Powerful longshore and rip currents will be present at most beaches. Large breaking waves and strong currents may impact harbor entrances and channels causing challenging boat handling.”

Forecasters also issued this Marine Weather Statement:

A slowly declining near 7 foot, medium period north swell is moving around the islands. A new northeast swell will arrive Monday. The slow decline of the north swell, in tandem with the incoming northeast swell, will produce surges within north-facing harbors and boat launches, mainly at Kahului and Hilo, the next couple of days.

Typically, swell heights of around 10 feet or greater create unsafe harbor transits. At these north swell heights, Piers 1A and 3B in Kahului Harbor become unsafe for cargo operations. Mariners should use increased caution when entering or leaving port, mooring, launching and retrieving vessels. Hilo Harbor typically experiences minor washup along Bayfront Road and portions of Lihiwai Street and Banyan Drive in south harbor.

The Hawaiʻi County Civil Defense noted the greatest impacts will occur during the high tide at 7:47 a.m. on Monday morning.

Forecasters say a downward trend is expected by Monday evening, with surf dipping below warning levels.