Marine Weather and Tide Forecast for Wainaku, HI

DISCUSSION
The latest satellite imagery this evening shows a fairly stable weather pattern around the islands with limited clouds under the influence of the subtropical ridge aloft. A weakening cold front northwest of the state will stall out before reaching the island chain with no significant impacts to island weather.

The main weather story into the upcoming week will be a steady strengthening of the trade winds from moderate levels on Sunday into the breezy to windy range by Tuesday, with wind speeds peaking on Wednesday across the island chain. Sea breeze wind coverage will diminish from Sunday into Monday as trade winds return with a vengeance. Wind speeds will likely reach wind advisory thresholds for some of our windier zones possibly starting on Tuesday night. The highest summits of Mauna Kea and Mauna Loa we may see wind advisory highlights starting as early as Monday morning. Relative humidity levels do not appear to fall low enough in the windier leeward areas to reach fire weather concerns at this time. We will continue to closely monitor these wind and humidity levels as this weather pattern evolves through the week.

In the long range outlook, global weather models are showing an upper level low moving into the Hawaii region. Current operational runs show the center of this low passing south of the Big Island by Wednesday. This low may bring up tropical moisture and instability into the windward and southeastern slopes of the Big Island, enhancing shower activity from Friday into next weekend.
The American (GFS) model also shows windward Maui picking up additional shower activity by Saturday. Stay tuned for more details as the forecast time period grows shorter.

AVIATION
Light trades winds will continue overnight, with land breezes developing in most areas. The trades will strengthen to moderate levels from east to west across the state Sunday, with some localized sea breezes possible in some of the more sheltered leeward areas. Low clouds and showers will favor windward and mauka areas mainly at night and during the early morning hours, with some isolated MVFR cigs/vsbys possible.

No AIRMETs are in effect and none are anticipated overnight.

MARINE
Easterly trade winds will increase to light to moderate levels on Sunday, strengthening to fresh to strong by Monday as high pressure builds to the north. This will lead to Small Craft Advisory conditions for the windier waters around Maui County and the Big Island starting Monday, with possible expansion to additional waters by Tuesday due to a combination of stronger winds and building seas.

Surf along north and west-facing shores will gradually decrease on Sunday before trending back up through the first half of the week as overlapping north-northwest swells arrive. Surf heights may near advisory levels on Monday and will likely reach them on Tuesday with a building north-northwest swell. A gradual downward trend is anticipated by Friday and through the weekend.

Surf along south-facing shores will remain up through Monday due to an out-of-season south swell, which will gradually subside Tuesday. Seasonal conditions will return around midweek with a mix of smaller southeast and south-southwest swells.

Surf along east-facing shores will begin to increase through the week as trade winds strengthen locally and upstream across the eastern Pacific.

FIRE WEATHER
Critical fire weather conditions are not anticipated through much of next week. Even as trade winds strengthen across all islands, these stronger wind speeds do not appear to line up over leeward areas where lower relative humidity levels may briefly reach our minimum thresholds.

HFO WATCHES/WARNINGS/ADVISORIES
None.