Marine Weather and Tide Forecast for Haena, HI

DISCUSSION

High stability prevails in the mid-levels as a typical breezy trade wind pattern remains established over the area. An upper low of low- latitude origin sits over the area bringing a slight reduction in stability as the inversion on this morning's observed soundings was rather soft and not as sharp as normal. As a consequence, the band of showers advancing through the state today has had no issue maintaining showers around 10-12kft deep even during the unfavorable peak heating period. This is in turn enhancing leeward shower penetration, especially over Oahu, and contributing to pockets of heavier showers over windward/mauka portions of all islands.

The next 24-30 hours will be characterized by little overall change except for a subtle veering of the low level flow to a more ESE direction. Given adequate moisture availability in the boundary layer, this has caused several members of today's guidance suite to hint at potential for banding within convergent ESE flow (i.e. Molokai/Lanai plumes) both this afternoon and tomorrow afternoon. This type of setup generally remains highly uncertain until it is underway, though it tends to favor southern/central Oahu including the Honolulu area urban corridor. At present, a loosely organized plume of mostly light rain originating over leeward Molokai is indeed streaming over southern portions of Oahu. This band of rain will likely persist for the next few hours. Weak convergence observed within this band suggests limited prospects for strengthening.

Upper-level flow maintains a cyclonic character well into next week aiding slightly lowered stability and providing a boost to trade wind showers. As surface high pressure remains established north of the islands, a breezy and seasonably wet trade wind pattern is forecast to prevail for the next several days.

AVIATION

A moderate to locally breezy trade wind pattern of mostly windward showers and passing low clouds will continue into early next week. Currently, scattered showers favor windward sides of the island chain. As winds turn more southeast, plumes of moisture will funnel additional showers across leeward areas during the afternoon and early evening hours. MVFR or even brief IFR ceilings and visibilities can be expected within any showers.

AIRMET Sierra remains in effect for mountain obscuration along windward sections across the island chain. These conditions will likely continue into the night.

AIRMET Tango remains in effect for low level moderate turbulence over and immediately S through W of all island mountains.

MARINE

Strong high pressure will remain anchored northeast of the state through tonight, keeping fresh to strong trades in place. A developing trough to the distant northwest is expected to ease the trades over the weekend into early next week. Light to moderate trades with localized sea breezes are expected over the western islands, while moderate to locally strong persist over the eastern end of the state.

A Small Craft Advisory (SCA) remains in effect for most marine zones east of Oahu through 6 am Saturday, and for some of the windier zones around Maui and the Big Island through 6 pm Saturday. The SCA may need to be extended for the typically windy waters over the eastern end of the state through the weekend.

Surf along north and west-facing shores will remain very small during the next 7 days. Surf along south-facing shores will hold at background levels through tonight. A series of small south and south-southwest swells will give a small boost to south shore surf over the weekend, with a further boost up to the seasonal average possible during the middle to latter part of next week.

Surf along east-facing shores will hold close to seasonal normals during the next 7 days.

HFO WATCHES/WARNINGS/ADVISORIES
Small Craft Advisory until 6 AM HST Saturday for Kaiwi Channel- Maui County Windward Waters.

Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Windward Waters- Big Island Leeward Waters-Big Island Southeast Waters.