UPDATE: 8:30 a.m.
The earlier wind advisory has been expanded to include all Hawaiian islands and extended through 6 a.m. Friday.
Northeast winds of up to 15 to 35 mph, with localized gusts up to 50 mph, are expected to accompany the cold front moving down from the western end of the island chain, according to the National Weather Service.
A wind advisory has been issued for the islands of Niihau, Kauai, and Oahu, effective from 6 p.m. today through 6 a.m. Thanksgiving Day.
The National Weather Service said northeast winds of 20 to 30 mph, with gusts up to 50 mph, are expected to accompany a cold front sweeping down the western end of the island chain tonight.
These strong and gusty winds will likely spread eastward across the rest of the state on Thanksgiving Day, forecasters warned, with the greatest threat for gusts at mountain ridges and leeward zones prone to downsloping.
In addition, exposed north and east slopes, along with beaches, may experience brief periods of strong wind gusts, especially immediately following the passage of the front.
Winds this strong can tear off shingles and knock down tree branches, officials warned, and make it difficult to drive, especially for drivers in high-profile vehicles.
The public should also watch out for falling tree branches when walking or driving, secure tents and awnings or take them down, and be prepared for power outages.
Forecasters expect a cold front to move across the Hawaiian isles, starting with the western isles tonight, before exiting east-southeast of Hawaii island on Thanksgiving Day.
The system is expected to generate a period of locally heavy rainfall in advance of the front, with strong northeast winds developing as it passes.
Additionally, a very large north swell is expected to build tonight, prompting a high surf warning for the north shores of Niihau, Kauai, Oahu, Molokai, and Maui, effective through 6 a.m. Friday.
Forecasters expect dangerously large, breaking waves of 20 to 25 feet along affected north shores.
The swell’s peak coincides with gusty, northeast winds, along with high tides expected during the early morning hours of Thursday and Friday.
This could result in significant overwash issues, officials said, and large wave run-up along north-facing shorelines.
The public should stay away from affected shorelines, be prepared for road closures, and postpone entering or leaving channels affected by high surf.
A small craft advisory and gale warning have also been issued for various channels and waters, with the former in effect until 6 a.m. Thursday, and the latter in effect from 6 a.m. Thursday to 6 a.m. Friday.
Surges are also expected in the north harbors on Maui and Hawaii island, starting Thursday, and lasting through the weekend. Mariners using the Kahului and Hilo harbors should exercise caution when entering port and when mooring or launching vessels.