Marine Weather and Tide Forecast for Launiupoko, HI

DISCUSSION
Scattered heavy showers developed over select areas across the state today due to the higher than normal moisture values combined with some afternoon day time heating. As we head into the late afternoon and evening, the intensity of the showers should generally decrease. The one exception is over windward Big Island and possibly east Maui, where we are seeing frequent trade wind showers. Hilo sounding showed over 2 inches of precipitable water values this afternoon and a wet trade wind pattern could very well continue for the Big Island through the middle of the week with frequent showers over windward areas.

Overall, broad troughing aloft combined with higher than normal precipitable water values and moderate easterly trade winds will continue to produce brief downpours at times through the middle of the week. Showers will generally favor windward areas during the overnight and morning hours with scattered leeward showers developing during the afternoons. Dewpoints will continue to linger in the upper 60s to low 70s, which should make temperatures feel warmer than normal.

Increased stability and stronger trade winds are expected by Thursday. Latest global guidance from the GFS and ECMWF are in good agreement with a strong high developing far north of the state, which should result in windy conditions. Winds could very well reach Wind Advisory thresholds Thursday into Friday for select areas downstream of terrain. Drier conditions are also expected during this time, but scattered showers should continue to ride in with the windy trade winds especially during the night and early morning hours.



AVIATION
Easterly tradewinds remain moderate to locally breezy and are primarily delivering showers over windward and mountain areas.
Some leeward areas have also experienced isolated afternoon showers today. The afternoon showers will dissipate overnight, while windward and mountain areas can still expect intermittent showers through tomorrow. Trade winds are expected to strengthen tomorrow, and returning stability should limit showers midweek.
MVFR conditions will occur within showers, and isolated IFR conditions are possible within heavier downpours. VFR will prevail elsewhere.

AIRMET Sierra is in effect for mountain obscuration for north through east sections of Oahu, the east section of Maui, and windward sections of the Big Island. Conditions over Oahu should improve this evening, while Maui and Big Island may still have conditions last overnight.

MARINE
Locally fresh trades become strong during the latter half of the week. Meanwhile, stability increases limiting prospects for thunderstorms.

A small, medium-period NNW declines through tonight with surf along exposed shorelines following suit. Another medium period NNW swell will provide an additional increase in surf along N shores by early tomorrow morning. This will then be followed by another similarly sized pulse on Tuesday. Surf along W shores remains steady as NNW swell declines in favor a new long period SSW swell.

A mix of small medium to long period S swells maintains average surf along S facing shores for the next several days. The aforementioned long period SSW swell will favor increased surf along S facing shores through today. Additional medium to long period S swell arrive through the week. Meanwhile, trades maintain choppy short period surf and fresh easterly swell through the week.

Tides peak around 2.5 to 3.0 ft MLLW today. Minor overwash of low lying coastal areas will be possible during times of high tide.



HFO WATCHES/WARNINGS/ADVISORIES
None.