West Side

Tonight: Mostly cloudy with isolated showers early in the evening, then partly cloudy in the late evening and overnight. Haze through the night. Lows 66 to 72. West winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Saturday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Haze through the day. Highs 77 to 82. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Isolated showers early in the evening. Haze through the night. Lows 66 to 72. Light winds. Chance of rain 20 percent.

South Side

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Haze. Lows 65 to 74. West winds up to 10 mph in the evening becoming light.

Saturday: Mostly sunny in the morning then becoming partly sunny. Haze. Highs around 85. North winds up to 10 mph shifting to the west around 10 mph in the afternoon.

Saturday Night: Partly cloudy. Haze. Lows 64 to 74. Light winds becoming east up to 10 mph after midnight.

North Shore

Tonight: Mostly cloudy. Isolated showers early in the evening, then scattered showers in the late evening and overnight. Haze through the night. Lows around 68 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 40 percent.

Saturday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Haze through the day. Highs 78 to 83 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Saturday Night: Partly cloudy. Isolated showers early in the evening, then scattered showers in the late evening and overnight. Haze through the night. Lows around 69 near the shore to around 50 near 5000 feet. East winds up to 10 mph. Chance of rain 40 percent.

Central Maui

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Haze. Lows 64 to 69. East winds up to 10 mph in the evening becoming light.

Saturday: Mostly sunny in the morning then becoming partly sunny. Haze. Highs 81 to 86. Light winds becoming north up to 10 mph in the afternoon.

Saturday Night: Partly cloudy. Haze. Lows around 66. Light winds.

Upcountry

Tonight: Mostly cloudy. Isolated showers early in the evening, then scattered showers in the late evening and overnight. Haze through the night. Lows around 44 at the visitor center to around 42 at the summit. Light winds. Chance of rain 40 percent.

Saturday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Haze through the day. Highs around 60 at the visitor center to around 64 at the summit. Light winds. Chance of rain 40 percent.

Saturday Night: Partly cloudy. Isolated showers early in the evening. Haze through the night. Lows around 44 at the visitor center to around 42 at the summit. Light winds becoming northeast up to 10 mph after midnight. Chance of rain 20 percent.

East Maui

Tonight: Mostly cloudy. Isolated showers early in the evening, then scattered showers in the late evening and overnight. Haze through the night. Lows around 68 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 40 percent.

Saturday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Haze through the day. Highs 78 to 83 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Saturday Night: Partly cloudy. Isolated showers early in the evening, then scattered showers in the late evening and overnight. Haze through the night. Lows around 69 near the shore to around 50 near 5000 feet. East winds up to 10 mph. Chance of rain 40 percent.

Lanai City

Tonight: Mostly cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Haze through the night. Lows 61 to 66. Light winds. Chance of rain 40 percent.

Saturday: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Haze through the day. Highs 71 to 79. Light winds becoming southwest up to 10 mph in the afternoon. Chance of rain 40 percent.

Saturday Night: Mostly cloudy with scattered showers early in the evening, then partly cloudy in the late evening and overnight. Haze through the night. Lows around 63. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Kaunakakai

Tonight: Mostly cloudy. Isolated showers early in the evening. Haze through the night. Lows 56 to 72. East winds up to 10 mph. Chance of rain 20 percent.

Saturday: Partly sunny. Haze through the day. Isolated showers in the afternoon. Highs 69 to 86. Light winds. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Isolated showers early in the evening. Haze through the night. Lows 56 to 72. Light winds. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light winds will prevail through early next week, with land and sea breezes common over most of the state. A rather dry pattern will persist tonight and Saturday. A few showers will affect east and southeast facing slopes overnight, and a few leeward showers will be possible Saturday afternoon. The airmass will moisten up Sunday through Tuesday as the moisture associated with an old trough moves over the state. This will bring an increase in showers, some of which could become heavy with even a few rumbles of thunder possible early next week as a disturbance aloft dives southward over the state. A return to more typical trade wind weather featuring mainly windward and mauka showers appears take hold during the middle to latter part of next week.

Discussion

Currently at the surface, a 1012 mb low is positioned around 600 miles north-northwest of Kauai, while a 1030 mb high is centered around 1450 miles north-northeast of Honolulu. Between these two features lies a trough of low pressure which is located around 150 miles northwest of Kauai. Infrared satellite imagery shows partly to mostly cloudy conditions across the state. Radar imagery shows a few decaying leeward showers along with a few showers moving into east and southeast facing slopes and coasts. Main short term focus revolves around trends in the winds and rain chances during the next few days.
The low north-northwest of the islands and the high to the distant north-northeast will shift eastward tonight through the weekend, then dampen into a trough over the islands early next week. Winds will change little through early next week, with land and sea breezes dominant over most of the state, with light to moderate east-southeast winds persisting in unsheltered areas around Maui and the Big Island. The troughing over the islands will gradually dampen out during the middle and latter part of next week as high pressure builds north. This should allow a gradual return and strengthening of the trade winds across the state.
As for the remaining weather details, the overall pattern will remain mostly unchanged and rather dry through Saturday night. A few showers will remain possible over east and southeast facing slopes and coasts overnight and during the morning hours, with a few showers developing in leeward areas Saturday afternoon then fizzling out in the evening. The airmass will moisten up Sunday through Tuesday as the moisture associated with an old trough moves over the state. A land/sea breeze pattern will remain in place, with showers favoring interior and leeward areas during the afternoon and evening hours, with most showers mostly over the coastal waters or near the immediate coast overnight. A disturbance aloft diving southward over the state could bring locally heavy rainfall and even a few thunderstorms to portions of the island chain early next week. A return to more typical trade wind weather featuring mainly windward and mauka showers appears take hold during the middle to latter part of next week.

Aviation

A low pressure system northwest of the Hawaiian Islands will continue to weaken the ridge over the region. Expect light southerly to southeasterly winds for the next few days. Land and sea breezes will develop over each island through the weekend. Fairly stable conditions aloft will keep shower activity to a minimum through Saturday. A strong upper level subtropical jet stream will produce high clouds and moderate upper level turbulence across the entire state through tonight and possibly into Saturday.
AIRMET TANGO remains in effect for moderate turbulence between FL280 and FL400.

Marine

Locally fresh southeast winds will gradually ease and become light and variable by Sunday as a low pressure trough northwest of the Islands slowly weakens and shifts northward. Light flow will continue into Monday and Tuesday. Trades eventually return midweek as surface high pressure builds north of the region. A slight chance of thunderstorms remains northwest of Kauai through late tonight.
A small long-period northwest swell is forecast to build in overnight, peak Saturday night or Sunday, then fade through early next week. Surf along north and west facing shores should remain near or below average, well shy of High Surf Advisory (HSA) criteria. By Thursday, a medium long-period north northwest swell is progged to enter the waters and produce surf that may approach HSA.
Multiple small early season south swells will maintain small background southerly energy into the coming week. Weak upstream trade wind flow will keep surf along east facing shores near or below seasonal averages.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov