Marine Weather and Tide Forecast for Makena, HI

DISCUSSION
Light to moderate trade winds are being supported by a weakening high pressure cell far NE of the islands. Like last night, satellite and radar images show limited and small patches of low-level moisture approaching most islands from the E, and a relatively dry night is anticipated outside of a few brief windward showers.

The high to the distant NE will diminish Friday and trade winds will ease as the low-level pressure gradient slackens. The light trades will persist through the weekend, allowing land and sea breezes to prevail over sheltered leeward areas. Nighttime land breezes will lead to mostly clear conditions leeward, with just a few windward showers. The afternoon sea breezes will drive cloud and shower formation over leeward and interior areas.

A shortwave trough will dig toward the islands from the NW Friday and Saturday, developing into a closed low that moves close to the islands this weekend. While there remains some uncertainty as to where the core of the low will eventually move, confidence is increasing that the island atmosphere will become destabilized by this feature, especially Saturday night and Sunday. The potential for thunderstorms and/or locally heavy showers has been included in the forecast for portions of the area. PWAT will be somewhat limited, thus widespread coverage of rainfall is not expected, but the showers that do occur will have the potential to become heavy.
One of the more likely areas for this to occur would be the Big Island's Kona slopes on Sunday afternoon.

Trade wind speeds will increase early next week as new high pressure to the distant NW builds eastward. Stability will also increase as the low aloft weakens and moves away to the NE.

AVIATION
High pressure north of the state will maintain moderate trade winds over the region through Friday evening. Relatively dry and stable conditions are expected. VFR flight conditions will prevail at most locations, but brief MVFR ceilings and visibility will be possible within any showers that pass through.

A weak eddy just southwest of the Big Island will keep the Kona and Kau coasts shrouded in clouds most of the night. Lee-side clearing should occur shortly after sunrise. In the afternoon, cumulus build- ups will redevelop along south and west facing slopes of the Big Island and linger through the evening.

MARINE
Moderate to locally fresh trade winds are expected to slowly decline to gentle to moderate speeds on Friday through Saturday, as a series of fronts pass far north of the state. Isolated thunderstorms could be possible Saturday night through Sunday for the windward waters as an upper low moves through the area. Winds should then gradually strengthen Sunday into the first half of next week as high pressure builds north of the state. Winds could potentially reach Small Craft Advisory levels for the windier waters and channels around Maui County and the Big Island by next week Monday.

For north facing shores, a pair of overlapping small, short period north swells should maintain small surf in place along north- facing shores through this weekend. A short lived small, short to medium period northeast swell is expected Saturday night through Sunday.
This will also give east facing shores a slight bump on Sunday.
Although there is some uncertainty on how strong the event will be, there is the potential for the arrival of a moderate long period north- northwest swell as early as Sunday and likely peaking next Monday, below advisory levels for north facing shores. This swell could linger through the middle of next week as it slowly fades.

The current long period south southwest swell will continue to gradually fade over the next few days. Buoys near Samoa have steadily risen throughout the day and plateaued at moderate levels, and will translate to a moderate, long period south swell that will slowly fill in Saturday, peak Sunday and hold into Monday then gradually decline through the middle of next week. This swell will may boost surf along south facing shores to near advisory levels during its peak.

HFO WATCHES/WARNINGS/ADVISORIES
None.