Strong and gusty trade winds are expected into Thursday as high pressure builds south toward the state. Windward and mauka shower chances increase later tonight and Thursday as a band of moisture accompanying a decaying frontal boundary moves from north to south across the state. Moderate to locally breezy trades will return Friday.
Locally strong trade winds will continue tonight before gradually weakening through the second half of the week. A dying frontal boundary will push through the island chain tonight into Thursday, providing an increase in shower activity. Windward and mountain areas will see most of the showers, but leeward areas could see some spillover showers as well. MVFR conditions are expected within showers while VFR prevails elsewhere. Showers will quickly decrease during the afternoon across Kauai and Oahu, and linger around Maui County and the Big Island a bit longer on Thursday.
AIRMET Tango is in effect for low level moderate turbulence downwind of terrain, upper level moderate turbulence between FL350 and FL380, and for strong surface winds 30 kt or greater over Maui County and the Big Island. Expect the strong surface winds to weaken by tomorrow morning, and the upper level moderate turbulence to diminish by early tonight. AIRMET Tango will likely remain in effect for low level moderate turbulence through the next several days.
Mountain obscurations are likely across windward sections of the islands as the frontal boundary moves down the island chain later tonight.
Strong high pressure north of Hawaii will maintain fresh to locally gale force winds across the marine areas tonight. A Gale Warning is in effect through 6 am Thursday for the windier waters and channels around Maui County and the Big Island. The current Small Craft Advisory (SCA) has been extended for all other coastal water zones through 6 pm Thursday. A front will drop south from the northern offshore waters to reach the central waters as it weakens tonight. This disturbance will bring increased shower activity to the area through Thursday. Through the weekend, the trade winds will trend down slightly to fresh to locally strong speeds across all waters.
PacIOOS Buoy 51201 near Waimea Bay has recently observed (as of 7 pm this evening) the incoming north-northwest swell energy at nearly 11 feet with a 15 second period. This large, long-period north-northwest swell (340 deg) will peak late tonight into early Thursday morning before declining through Friday. A High Surf Advisory (HSA) remains in effect for north-facing shores of Kauai, Oahu, Molokai and Maui and west-facing shores of Kauai and Oahu through Thursday afternoon. Seas will exceed 10 feet late tonight into Thursday so the Small Craft Advisory will also include large seas. Surf will decrease Friday followed by a north swell this weekend which could push surf back to advisory levels on Sunday.
Surf along east-facing shores will remain rough and choppy due to the strong trade winds through Friday, then may diminish slightly this weekend. A small, long-period south swell may bring a small bump to south shore surf through Thursday. Surf becomes tiny again Friday into the weekend for south-facing shores.
High Surf Advisory until 6 PM HST Thursday for Kauai North-Maui Central Valley North-Maui Windward West-Molokai North-Molokai West-Molokai Windward-Niihau-Oahu North Shore-Waianae Coast- Windward Haleakala.
Wind Advisory until 6 AM HST Thursday for Big Island North-Big Island South-Big Island Southeast-Kahoolawe-Kohala-Lanai Leeward- Lanai Mauka-Lanai Windward-Maui Central Valley North-Maui Central Valley South-Maui Leeward West-Molokai Leeward South- Molokai North-Molokai Southeast-Molokai West-Molokai Windward- South Haleakala.
Small Craft Advisory until 6 PM HST Thursday for Big Island Windward Waters-Kaiwi Channel-Kauai Channel-Kauai Leeward Waters- Kauai Northwest Waters-Kauai Windward Waters-Maui County Leeward Waters-Maui County Windward Waters-Oahu Leeward Waters-Oahu Windward Waters.
Gale Warning until 6 AM HST Thursday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters-Maalaea Bay- Pailolo Channel.
