A high surf advisory remains in place for the north- and west-facing shores of most isles, effective until 6 a.m. Thursday due to a large, north-northwest swell.

The National Weather Service expects that swell to peak today, boosting surf to 15 to 20 feet along the north-facing shores of Kauai County, Oahu, Molokai, and Maui.

Surf of 10 to 15 feet, meanwhile, is expected along the west-facing shores of Kauai County, Oahu, and Molokai today.

The public should beware of strong, breaking waves and strong currents, which will make swimming dangerous.

“When in doubt, don’t go out,” said the advisory. “Large breaking surf, significant shorebreak, and dangerous currents make entering the water very hazardous.”

A wind advisory has also been issued for Kauai County, Oahu, and Maui County, starting 6 p.m. today until 6 a.m. Thursday.

Forecasters say a cold front near Kauai will move down the island chain later today and tonight, with strong winds developing behind it.

Northeast winds of 20 to 30 mph, with localized gusts over 50 mph, are expected during this timeframe.

“Winds this strong can knock down holiday decorations and tree branches and blow around unsecured objects,” the NWS said. “Strong gusts can make it difficult to drive, especially for high-profile vehicles.”

Winds will be particularly gusty over and downwind of mountains and through valleys, forecasters said.

The public should beware of falling tree branches when walking or driving, secure tents and awnings, and be prepared for power outages.

The small craft advisory for most Hawaiian waters has been extended until 6 p.m. today, when a gale warning goes into effect. The gale warning remains in effect until 6 p.m. Thursday.