A powerful Kona storm will near the state producing periods of hazardous weather impacts across the Hawaiian Islands through the weekend. Expect a combination of threats ranging from significant flash flooding, damaging winds, strong to severe thunderstorms, and snow and ice over the highest Big Island summits. Southerly to southwesterly winds will be strongest from Friday to Saturday and will produce damaging wind gusts. The highest threats for damaging winds remain along north and east of the island mountains. Unsettled wet weather conditions with decreasing southwesterly wind trends will continue into early next week. This Kona storm begins to lift northward on Monday, and unsettled weather will start to ease across the Hawaii region. High pressure will build back in north of the state on Wednesday allowing trade winds to return spreading from north to south down the island chain.
Shower activity continues across the Hawaiian Islands tonight. Maui will see showers moving in by 10 PM, with the Big Island seeing showers after midnight. Expect widespread MVFR to IFR in showers, locally as low as LIFR. Winds will remain primarily out of the south. Southerly winds will become gusty and strong Friday, with widespread gusts up to and over 35 kts.
AIRMET Sierra remains in effect all islands due to mountain obscuration. This is expected to in effect all night.
AIRMET Tango remains in effect for moderate upper-level turbulence between FL240 and 360. This ongoing Kona low should keep turbulence prevailing over the next few days.
AIRMET Zulu is also in effect, as high clouds from these showers present icing concerns between 120 and FL260. This is also expected to continue through the night.
A powerful Kona storm will continue to bring heavy rain, thunderstorms, and rough seas to the Hawaiian coastal and offshore waters into the weekend. Southerly winds will strengthen tonight into the weekend as a Gale Warning has been issued for the waters around Kauai and Oahu through Friday night. Winds are expected to near Maui County Saturday and Saturday night to near gale-force, so a Gale Watch has been posted for those areas during that time. These strong to gale- force winds will last into the weekend in association with a band of heavy showers and thunderstorms pushing eastward across the forecast area associated with the Kona storm.
A series of small, short to medium period west to west-northwest swells will bring small to moderate surf to north and west facing shores through the remainder of the week. Kauai will block some of this swell energy from reaching Oahu and Maui, but it will make it into the west facing shores of the Big Island. The next west- northwest swell is expected to build Friday into the weekend. Additionally, a small, medium period north swell originating from Alaska Peninsula gap winds is expected to arrive slowly through Friday and peak Saturday before gradually declining.
Rough and choppy surf will continue along south-facing shores due to the southerly wind direction. These south winds will intensify tonight into Friday, causing south shore surf to build Friday into the weekend, likely reaching advisory levels. Once southerly winds diminish early next week, a small to moderate, long-period south swell generated by a gale force low east-southeast of New Zealand will arrive along south-facing shores and build into midweek.
Choppy surf along east-facing shores will continue to trend downward and remain below seasonal levels as south to southeast winds prevail.
Flood Watch through Saturday afternoon for all Hawaiian Islands.
High Wind Warning until 6 AM HST Sunday for Niihau, Kauai, Oahu, Molokai, Lanai, Kahoolawe, and Maui.
High Wind Warning until 6 PM HST Sunday for Big Island Summits- Haleakala Summit.
High Wind Watch from 6 AM HST Friday through late Saturday night for Big Island lower elevation areas.
Winter Storm Warning until 6 PM HST Saturday for Big Island Summits.
Gale Warning until 6 AM HST Saturday for Kauai Channel-Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters-Oahu Leeward Waters-Oahu Windward Waters.
Gale Watch from Saturday morning through Saturday evening for Alenuihaha Channel-Kaiwi Channel-Maui County Leeward Waters-Maui County Windward Waters-Oahu Windward Waters.
