6 p.m. UPDATE

A high surf warning has been issued for the north- and west-facing shores of various Hawaiian isles, starting Wednesday morning.

The warning covers the north and west shores of Niihau, Kauai, Oahu, and Molokai; the north-facing shores of Maui; the west-facing shores of Hawaii island, effective from 6 a.m. Wednesday to 6 p.m. Thursday.

Forecasters say a very large, northwest swell will build late tonight and peak Wednesday night and early Thursday. This, combined with the strong, west winds, will produce rough and hazardous ocean conditions into Thursday.

Surf of 30 to 40 feet is expected along north-facing shores, and 20 to 30 feet along west-facing shores.

Officials warn the public to “stay away from the shoreline along the affected coasts” and prepare for road closures. Additionally, people should postpone entering or leaving channels affected by the high surf until it subsides.

High winds, meanwhile, are whipping through the isles as a cold front approaches Kauai this evening.

These high winds will continue increasing and sweep from west to east overnight, forecasters said, prompting a wind advisory for all isles, effective from midnight today through midnight on Wednesday.

EARLIER TODAY

More high winds are on the way tonight, according to weather forecasters, as a cold front approaches the Hawaiian islands from the northwest today.

The National Weather Service has issued a wind advisory for all islands, effective from midnight till midnight on Wednesday.

“A strong cold front will approach from the northwest today, then sweep from west to east through the islands tonight through Wednesday night,” said forecasters. “Strong and gusty winds will begin after midnight tonight and continue through midnight Wednesday night across the lower elevations all islands.”

Southwest-to-west winds of 25 to 35 mph, with gusts over 50 mph, are expected across portions of the state.

“Winds this strong can tear off shingles, knock down tree branches, blow away tents and unsecured objects, and make it difficult to drive, particularly for high profile vehicles,” the NWS said.

The strongest winds will be downwind of terrain or where wind is funneled effectively, including valleys and areas by coastal water channels.

Officials warn of a higher risk of tree falls to due above-average rainfall and winds coming from the opposite direction of normal trades. Tents and awnings should be secured or taken down, and people should be prepared for power outages.

Even stronger winds are expected at Big Island summits, where the NWS has issued a high wind warning, effective until 6 p.m. Sunday. Summits can expect southwest winds of 55 to 65 mph, with high gusts today of up to 70 to 90 mph, and even higher gusts tonight.

Travel to summits should be postponed until conditions improve, forecasters said.

A high wind watch is also in effect for the Haleakala summit from 6 p.m. today until 6 a.m. Thursday.

Forecasters say the winds will ease on Thursday. Warmer weather should return early next week.

A large, northwest swell is also expected to build late tonight and early Wednesday, boosting surf of 18 to 25 feet to north-facing shores on Wednesday morning, and 30 to 40 feet by Wednesday afternoon.

A small craft advisory is in effect for Alenuihaha Channel and Big Island southeast waters until 6 a.m. Thursday.