West Kaua’i

Tonight: Partly cloudy with isolated showers. Lows 70 to 75 near the shore to around 62 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs 83 to 89 near the shore to around 75 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 68 to 73 near the shore to around 61 above 3000 feet. East winds around 10 mph. Chance of rain 40 percent.

South Kaua’i

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows around 73. East winds around 15 mph. Chance of rain 20 percent.

Wednesday: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 80 to 88. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 72. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Mostly cloudy with scattered showers. Lows 64 to 70 in the valleys to around 60 above 4000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Wednesday: Partly sunny with scattered showers. Highs 74 to 81 in the valleys to around 65 above 4000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Wednesday Night: Mostly cloudy with scattered showers. Lows 63 to 69 in the valleys to around 58 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

North Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 66 to 73. East winds 10 to 15 mph. Chance of rain 30 percent.

Wednesday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 76 to 85. East winds 10 to 15 mph. Chance of rain 30 percent.

Wednesday Night: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 64 to 72. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Tonight: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 76. East winds 10 to 15 mph. Chance of rain 40 percent.

Wednesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 73 to 85. East winds 10 to 15 mph. Chance of rain 40 percent.

Wednesday Night: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows 64 to 75. East winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Breezy and mostly dry trade wind weather will persist through Wednesday. Trade winds will gradually decrease Thursday into Friday with a slight increase of shower coverage expected by Thursday. Light to moderate trade winds are expected over the weekend with mostly dry conditions on Saturday and scattered showers on Sunday.

Discussion

Strong high pressure far northeast of the state will maintain breezy trade winds through Wednesday. Scattered showers will continue to ride in with the trade winds and will mainly be focused over windward and mauka areas with a few showers making its way to leeward areas as well due to the breezy trades. As the high weakens far northeast of the state, trade winds will gradually weaken Thursday into Friday with moderate trade winds expected by Friday. A slight increase of shower coverage is possible Wednesday night into Thursday, but generally shower intensities will continue to remain light due to stable conditions in the lower levels.
In the mid to upper levels of the atmosphere, water vapor imagery is showing a weak upper level low located just west of the state. Very little impacts are expected from the upper level low, but some mid to high level clouds are expected to stream over the state tonight and once again on Wednesday night into Thursday. The cloud cover was nudged up a touch to show an increase of cloudiness on these days.
Over the weekend, mostly fair weather is expected with moderate trade winds. Saturday looks to be a mostly dry day with ample sunshine and a few isolated showers. Sunday should see an increase of shower coverage with some scattered showers expected. With the lighter trade wind pattern, we could see some localized sea breezes with afternoon clouds and showers over select leeward areas especially on Sunday.

Aviation

Breezy trades deliver clouds and scattered showers windward and mauka through the forecast period. Pockets of MVFR are likely but are forecast to remain isolated in nature while VFR prevails.
AIRMET Tango remains in effect for low-level lee turb.

Marine

Moderate to locally strong trade winds will slowly decrease and become gentle to locally fresh by Saturday as high pressure to the far northeast remains nearly stationary and weakens slowly through the week. A Small Craft Advisory (SCA) is in effect for the usual windier waters and channels around Maui County and the Big Island through Wednesday afternoon.
Surf along south facing shores will remain small for the remainder of the afternoon before a tiny to small long period southwest swell is expected to start filling in late tonight into Wednesday. A larger swell from a fetch near New Zealand is likely to bring a moderate long period south- southwest swell as early as Friday, and peak Saturday potentially near High Surf Advisory (HSA) criteria.
East-facing shore surf will remain choppy due to the moderate trade winds. A combination of a strong high pressure to the far northeast and a low near California earlier this week has produced the potential for a moderate medium period east swell to fill in Thursday, peak Friday, and decline through the weekend. Surf along north facing shores will remain small.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 8 PM HST Wednesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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