A rising swell bringing waves of up to 20 feet prompted the National Weather Service to issue a high surf advisory for north shores of most islands through Wednesday evening.

Surf along north shores of Oahu, Kauai, Niihau, Molokai and Maui is expected to rise to 6 to 10 feet starting tonight and rise to 16 to 20 feet late tonight into Wednesday.

Strengthening tradewinds of 15 to 25 mph, gusting to 45 mph may also kick up surf on east shores, where an advisory is also likely to be posted on Wednesday through the weekend.

The tradewinds are also expected to bring rainy weather to windward and mauka areas tonight through Wednesday. Some of the showers may be blown over the leeward areas.

Organizers of the Billabong Pipe Masters in Memory of Andy Irons said the surf contest is likely to resume Wednesday with the new swell and finish on Thursday.

The National Weather Service said surf conditions could be hazardous because of the big waves, shorebreak and strong currents.

“Beachgoers, swimmers and surfers should heed all advice given by ocean safety officials and exercise caution,” forecasters said. “When in doubt, do not go out.”