Surf remains high and potentially dangerous on south shores of all islands.

The National Weather Service extended a high surf advisory until 4 a.m. Wednesday.

It had been scheduled to expire Tuesday evening.

Forecasters said the declining south swell continues to produce above-normal surf of 5 to 8 feet.

It could be another busy day for lifeguards.

Ocean Safety personnel performed 122 rescues and took more than a thousand preventive actions on Monday. Lifeguards recorded 104 rescues and 104 preventive actions on the south shore; 14 rescues and 520 preventive actions on the west side; and four rescues and 595 preventive actions at Sandy Beach.

Forecasters warn the high surf will continue to bring strong breaking waves and shore break and create rip currents that can make swimming difficult and dangerous.

"Beachgoers, swimmers and surfers should heed all advice given by Ocean Safety officials and exercise caution. Know your limits. When in doubt, do not go out," the National Weather Service said in an advisory.