Photo Credit: Tyler Rooke

West Side

Today: Mostly sunny with isolated showers. Highs 81 to 87. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows 68 to 74. East winds 10 to 15 mph. Chance of rain 20 percent.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs 81 to 87. Northeast winds around 10 mph. Chance of rain 20 percent.

South Side

Today: Sunny. Isolated showers in the afternoon. Highs around 87. North winds around 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 67 to 72. North winds around 10 mph.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs around 87. North winds 10 to 15 mph. Chance of rain 20 percent.

North Shore

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 78 to 85 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 30 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows around 70 near the shore to around 52 near 5000 feet. Southeast winds around 10 mph. Chance of rain 40 percent.

Monday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 78 to 84 near the shore to around 67 near 5000 feet. Northeast winds around 10 mph. Chance of rain 40 percent.

Central Maui

Today: Sunny. Isolated showers in the afternoon. Highs 84 to 90. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 66 to 71. Northeast winds around 10 mph.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs around 86. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Upcountry

Today: Mostly sunny with isolated showers. Highs around 60 at the visitor center to around 57 at the summit. Southeast winds around 10 mph in the morning becoming light. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows around 48 at the visitor center to around 45 at the summit. Light winds becoming north around 10 mph after midnight. Chance of rain 20 percent.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs around 60 at the visitor center to around 57 at the summit. East winds around 10 mph. Chance of rain 20 percent.

East Maui

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 78 to 85 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 30 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows around 70 near the shore to around 52 near 5000 feet. Southeast winds around 10 mph. Chance of rain 40 percent.

Monday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 78 to 84 near the shore to around 67 near 5000 feet. Northeast winds around 10 mph. Chance of rain 40 percent.

Lanai City

Today: Mostly sunny. Scattered showers in the afternoon. Highs 71 to 79. Northeast winds around 10 mph. Chance of rain 30 percent.

Tonight: Mostly clear. Lows around 66. Northeast winds around 10 mph.

Monday: Sunny. Isolated showers in the afternoon. Highs 73 to 81. Northeast winds around 10 mph. Chance of rain 20 percent.

Kaunakakai

Today: Mostly sunny. Isolated showers in the afternoon. Highs 71 to 88. Northeast winds around 10 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers after midnight. Lows 59 to 73. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 72 to 88. Northeast winds around 10 mph shifting to the north in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light trade winds will deliver a few windward showers into Monday, with the potential for an increase in showers over windward and southeast Big Island tonight. Winds will become light and variable by Tuesday, then remain that way through the week, with mostly dry weather. Expect mostly clear nights and mornings giving way to afternoon interior clouds and isolated showers. Trade winds may return next weekend.

Discussion

A relatively weak (1021 mb) surface high centered about 800 miles NW of the islands is supporting a light to locally moderate trade wind flow this morning. The high pushed moisture associated with a dissipated front over Kauai overnight, leading to some beneficial rainfall. This moisture band is now becoming increasingly diffuse and lifting away from Kauai, so shower coverage should be trending down. Radar currently shows isolated small showers moving into windward coasts of all islands, while morning soundings indicate a strong subsidence inversion near 5000 feet at PHTO, with the inversion a little higher and weaker at PHLI.
The short term forecast expects the light to moderate trade winds to persist, delivering just a few showers to windward areas. Winds will likely be sufficiently light to allow afternoon sea breezes to drive some cloud development. A surface trough about 450 miles SE of the Big Island will move W at 15 to 20 mph, and guidance indicates that some of the associated moisture may clip the Big Island later today into Monday, bringing an increased chance of showers to the Kau, Puna and Hilo Districts. The stable island atmosphere will likely limit rainfall totals over areas that could use a soaking rain.
The high will weaken tonight and Monday before dissipating on Tuesday. In its place, a surface ridge is expected to extend over the islands from the E, with trade winds becoming light and variable. The light winds will allow for mostly clear skies during nights and mornings, with some interior and upslope clouds in the afternoons. With a strong mid-level ridge building overhead, rainfall chances will be minimal. This pattern is expected to persist through Friday, with another weak front potentially nearing Kauai by next weekend, potentially leading to increasing trade winds.

Aviation

Trade winds will steer bands of light showers off the Pacific towards mainly windward slopes and coasts. Light sea breezes will return to leeward coasts this afternoon and will serve to focus afternoon shower activity over island interiors. A sharp trade wind inversion around 06 kft over the eastern half of the state will serve to restrict any shower development over the Big Island to the lower elevations.
Brief MVFR ceilings and visibilities are to be expected in showers, otherwise VFR conditions will prevail all areas.

Marine

A brief increase in trade winds will develop today with light to moderate trades lasting into Monday, as a surface ridge builds far to the north. Wind speeds will weaken yet again from Tuesday onward and turn more from the southeast direction as another cold front approaches the islands from the northwest.
A small, declining, short period north-northwest swell will be reinforced by a medium period north-northwest (340 degrees) swell today. This swell will decline on Tuesday, though a similarly sized pulse of northwest swell is due late Wednesday or Thursday.
The series of late season south swells will continue through the week. Long period, south-southwest swell (190-200 degrees) will hold today. An overlapping pulse of south swell (180-190 degrees) will maintain similarly sized surf Monday, with a gradual decline on Tuesday and Wednesday. Another pulse of southwest swell is due late next week.
Aside from areas exposed to wrapping north-northwest swell, east shore surf will continue to be small due to the lack of significant upstream trade winds.
Higher than predicted water levels have been observed across the Hawaiian Islands this past week. Minor coastal flooding is possible during the early morning high astronomical tides through Tuesday, with Monday seeing the highest tides. A Coastal Flood Statement continues for all vulnerable coastal areas.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov