A high surf advisory has been issued for the north and west facing shores of Niihau, Kauai, and Oahu, effective until 6 p.m. Wednesday.

The National Weather service says a northwest swell will produce advisory-level surf of 10 to 16 feet along north facing shores, and up to 8 to 12 feet along west facing shores of those isles through Wednesday afternoon.

Officials warn of strong, breaking waves and strong currents, which will make swimming dangerous.

Forecasters expect a more northerly swell to come in late Wednesday into Thursday, which may require an extension of the high surf advisory for north facing shores.

Surf for south facing shores, meanwhile, remains small at 1 to 3 feet today and Wednesday.

Surf for east facing shores, which are experiencing choppy, rough seas due to tradewinds upstream of the islands, is expected to decline from 2 to 4 feet today to 1 to 3 feet on Wednesday as those trades taper off midweek.