The National Weather Service extended a high surf advisory for south shores of all islands until 6 p.m. Sunday as a the first of a series of swells brought high waves to town shores on Oahu.

Surfers crowded south shore beaches on Oahu Thursday as the swell slowly built into the evening.

The National Weather Service says this is the first of a series of swells bringing 6- to 10-foot waves to south shores through the early part of next week.

While the surf may be fun for experienced beachgoers, the National Weather Services warns the waves can also be dangerous because of strong rip currents and breaking surf on shore that could wash beachgoers into the ocean.

Today could bring good surf on all shores. A small northwest swell is expected to boost surf on north and west shores. East shores may also get waves from a trade wind swell.

A reinforcement swell should arrive on south shores Saturday.

Two other storm near New Zealand could bring even more surf to south shores Sunday and Tuesday.

The National Weather Service says beachgoers and swimmers should heed advice given by lifeguards and exercise caution.

Boaters should also be aware of recreational surfers and bodyboarders using harbor channels to access surfing areas.