Strong winds and surf are expected for the state today, the National Weather Service said.

A high surf warning is in effect for the north-facing shores of Kauai County, Oahu, Maui, Molokai and Hawaii island through 6 p.m. Wednesday.

A large northwest swell building today is expected to peak tonight, weather officials said. Surf along affected shores is forecast at 15 to 20 feet this morning, rising to 20 to 50 feet tonight and hitting 24 to 30 feet Wednesday.

A high surf advisory also is in effect, for the east and west shores of Oahu and Molokai, and the east shores of Kauai, Maui and Hawaii island. Surf along affected west shores should reach 10 to 15 feet, rising to 14 to 18 feet tonight and Wednesday, forecasters said. East shores should see surf of 6 to 8 feet.

Expect ocean water occasionally sweeping across portions of beaches, very strong, breaking waves and strong longshore and rip currents. Breaking waves may occasionally impact harbors, making navigating the harbor channel dangerous, weather officials said.

A wind advisory also is in effect, for all islands through 6 p.m. today.

Northerly winds of 20 to 35 mph are expected with local gusts of over 50 mph. Strongest winds were expected over ridge tops and through mountain gaps as well as over leeward slopes.

Additionally, a high wind warning is in effect for the summit of Haleakala with winds of 55 to 75 mph, with higher gusts, expected. The warning also is in effect until 6 p.m. today.

The winds are expected to quickly weaken tonight through Wednesday.

Winds this strong can knock down tree branches and cause power outages, and drivers of high-profile vehicles should drive with extreme caution, the Weather Service said.

The winds were being caused by a cold front to the north that was expected to pass over the state tonight, allowing the strong winds to fill in behind it.