Moderate west-northwest winds with drier air will continue to fill in behind a dissipating front. Building high pressure north of the state will bring a return to a more typical trade wind pattern for Wednesday, with limited windward and mauka-focused showers continuing into early next week.
The latest analysis places a weakening front near the Big Island this afternoon, moving slowly southeastward. Visible satellite and radar imagery shows the shower band associated with this feature has become significantly more diffuse through the day, with only scattered showers now over the eastern end of the state, despite the presence of an upper trough just north of the islands. Strong westerly flow aloft continues to cause warning-level winds on the Big Island Summits and advisory-level winds for Haleakala summit. These conditions are expected to continue through tonight.
Elsewhere and otherwise, light to moderate west-northwest winds and much drier conditions are filling in from west to east in the wake of the front, with little in the way of showers and scattered clouds over the western half of the state. On Tuesday, the drier air will spread to the rest of the state as the dissipating front moves east of the area. Winds will shift out of the north through Tuesday, becoming northeast trades by Wednesday as high pressure builds to the north of the state. A return to a more typical trade wind pattern is anticipated for Wednesday through the second half of the week, with moderate wind speeds and clouds/showers favoring windward areas. Global models show a dry airmass sticking around through early next week, so have trended a bit lower with PoPs through the remainder of the forecast period.
A weakening frontal system near the Big Island is expected to dissipate over the next 24 hours of so. Skies have cleared over Kauai, Oahu and Molokai behind the front. Additional clearing over the remainder of Maui County is expected as the afternoon wears on. Some lingering clouds and showers will trail over the Big Island.
AIRMET Sierra for mountain obscuration is currently in effect for Maui and Lanai, but conditions are expected to improve over the next couple of hours.
AIRMET Tango is in effect for mechanical turbulence N through NE of the mountains on the Big Island.
Occasional light rime icing is expected in layered clouds above 15 kft from Maui eastward. Conditions will continue today, but some improvement is expected from west to east as the front moves away from the islands.
An increasingly diffuse front over the Big Island will continue to move SE and gradually dissipate through Tuesday. Clouds and showers associated with the front are diminishing in both coverage and intensity. Light to moderate W to NW winds will follow the front through tonight, except for moderate to fresh S to SW winds over Big Island waters. High pressure building NW of the islands will support a veering low-level flow starting Tuesday, with light to moderate NW to N winds becoming NE and strengthening somewhat after midweek.
A Small Craft Advisory for the Alenuihaha Channel and leeward Big Island waters has been allowed to expire as S to SW winds diminish, while increased seas in Kauai waters will require a SCA through Tuesday.
Surf along N and W facing shores will increase through this evening as a mixed-period NW swell builds, bringing elevated surf to exposed shores as the swell peaks overnight. This swell will gradually diminish as it becomes increasingly N the next couple of days. Otherwise, small swells from the SSE and SW will support small surf along S facing shores the next couple of days. Surf along E facing shores will remain very small, then gradually trend up as NE trade winds increase later in the week.
Wind Advisory until 6 AM HST Tuesday for Haleakala Summit.
High Wind Warning until 6 AM HST Tuesday for Big Island Summits.
Small Craft Advisory until 6 PM HST Tuesday for Kauai Northwest Waters-Kauai Windward Waters-Kauai Leeward Waters.
