Anticipated surf up to 20 feet on some shores prompted weather officials to issue a high surf advisory effective as of this evening.

Areas under the advisory include the north- and west-facing shores of Oahu, Molokai and Kauai County, and the north shore of Maui.

Forecasters at the National Weather Service expect surf up to 15 to 20 feet along the north- and west-facing shores of Kauai County, and the north-facing shores of Oahu, Maui and Molokai. The west-facing shores of Oahu and Molokai could see surf up to 9 to 13 feet.

The high surf advisory is scheduled to go into effect at 6 p.m. and run through 6 p.m. Thursday.

Strong breaking waves, shore break and strong currents could make swimming dangerous on affected beaches, weather officials warn.