Surf will remain elevated through this evening as a large, deadly swell declines into the evening.

A high surf advisory is in effect until midnight, downgraded Thursday afternoon from a high surf warning for north and east shores of all islands except for Lanai.

Surf is still in the 18- to 24-foot range this morning on north shores and 8- to 10-feet on east shores..

The wave heights are expected to decline to 15- to 20-feet on north shores and 5- to 8-feet on east shores.

Beachgoers should expect strong breaking waves, and strong longshore and rip currents making swimming dangerous, forecasters said.

An experienced Haleiwa surfer is missing after he was hit by two big waves at a surf break known as “Alligator Rock” Wednesday.

The high surf also closed the parking and pavilion area at Baldwin Park in Paia Wednesday and Thursday because of waves surging over the area, causing flooding.

Moderate to heavy harbor surges are also expected at Hilo and Kahului harbors.

The swell will also likely mean large breaking wave at the channel entrances, causing hazardous boating conditions.

At Haleiwa’s Alii Beach, the Reef Hawaiian Pro surf contest started Wednesday in clean, head-high to overhead surf. The contest will continue today, surf conditions permitting.