(BIVN) – The National Weather Service in Honolulu has issued a High Surf Warning for West Hawaiʻi shores.

“A long-period northwest swell will build through the day, peak tonight and early Thursday at dangerously high levels, then gradually diminish late Thursday and Friday,” the forecasters wrote in an early morning message. “Expect ocean water occasionally sweeping across portions of beaches, very strong breaking waves, and strong longshore and rip currents. Breaking waves may occasionally impact harbors making navigating the harbor channel dangerous.”

Surf will build to 4 to 8 feet this afternoon in North and South Kona, increasing to 8 to 12 feet tonight and Thursday. “There will likely be long lulls between the sets of larger waves as the swell builds later today,” the National Weather Service said. “Don’t be caught off guard when larger waves arrive suddenly.”

A High Surf Warning remains in effect for north- and west-facing shores of the other Hawaiian islands, where surf heights are expected to reach up to 35 feet.