West Kaua’i

Tonight: Partly cloudy with isolated showers. Lows 68 to 73 near the shore to around 61 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Sunday: Mostly sunny. Isolated showers in the morning. Highs 84 to 90 near the shore to around 77 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Sunday Night: Mostly cloudy in the evening, then partly cloudy with isolated showers after midnight. Lows 69 to 74 near the shore to around 62 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows around 72. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 81 to 88. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Sunday Night: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 73. East winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Mostly cloudy with numerous showers. Lows 64 to 69 in the valleys to around 58 above 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Sunday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 75 to 83 in the valleys to around 66 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Sunday Night: Breezy. Mostly cloudy with scattered showers. Lows 64 to 69 in the valleys to around 59 above 4000 feet. East winds up to 20 mph. Chance of rain 50 percent.

North Kaua’i

Tonight: Mostly cloudy. Numerous showers in the evening, then scattered showers after midnight. Lows 64 to 73. East winds up to 15 mph. Chance of rain 70 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 76 to 87. East winds up to 15 mph. Chance of rain 50 percent.

Sunday Night: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 65 to 74. East winds up to 15 mph. Chance of rain 40 percent.

East Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 64 to 76. Northeast winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs 74 to 86. East winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Sunday Night: Mostly cloudy with scattered showers. Lows 64 to 76. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Breezy trades focus clouds and showers windward and mauka for the next week especially at night and early morning.

Discussion

Strong stability prevails and is characterized by a stout trade wind inversion that slopes slightly downward from around 7kft at Kauai to 6kft at Hilo. Moisture remains trapped beneath the inversion leading to a rather impressive coverage of showers in recent nights despite synoptically dry and stable conditions. Suspect this pattern will continue as the latest modeling indicates high stability persisting through the forecast period. As such, strong June diurnal warming above cloud tops will easily suppress daytime convection while nighttime shower coverage overachieves. Shower intensity will remain light as capping remains strong and moisture depth remains relatively shallow. Mid-level ridging anchored N to NE of the islands maintains breezy trades for at least the next 7 days.

Aviation

Moderate to breezy and gusty trades will gradually increase through Monday. Low cigs and SHRA will be mostly focused over windward and mauka locations. Some spillover to leeward sides isn't out of the question. MVFR conds possible in any SHRA otherwise VFR prevails.
AIRMET Tango is in effect for mod turb downwind of island terrain. This will likely continue through the weekend as trade winds strengthen.

Marine

High pressure north of the region will strengthen and dominate through the forecast period. As a result, trade winds will increase a notch through the rest of this weekend and remain through next week. A Small Craft Advisory (SCA) for the windier waters and channels around Maui County and the Big Island remains in effect through Monday, but will likely need to be extended and possibly expanded in coverage as the trades strengthen.
A series of small, long-period, south swells originating near New Zealand will help boost surf heights to near the summer average (5 feet) throughout next week. The first of these should fill in Sunday into Monday, followed by another Wednesday into Thursday of next week.
Rough and choppy surf along east facing shores is expected to slightly increase into early next week due to the strengthening trade winds. Surf will remain at seasonable levels (nearly flat) along north facing shores throughout the forecast period, though select exposures could see some tradewind swell wrap.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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