West Kaua’i

Tonight: Breezy. Partly cloudy with isolated showers. Lows 67 to 72 near the shore to around 60 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Sunday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs 83 to 88 near the shore to around 74 above 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Sunday Night: Mostly cloudy with isolated showers. Lows 67 to 72 near the shore to around 60 above 3000 feet. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 20 percent.

South Kaua’i

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 71. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Sunday: Partly sunny. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs 79 to 87. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Sunday Night: Breezy. Mostly cloudy with scattered showers. Lows around 70. East winds 10 to 20 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Mostly cloudy. Breezy. Showers likely in the evening, then occasional showers after midnight. Lows 61 to 69 in the valleys to around 58 above 4000 feet. East winds 10 to 20 mph. Chance of rain 90 percent.

Sunday: Breezy. Occasional showers. Highs 73 to 80 in the valleys to around 64 above 4000 feet. East winds 10 to 25 mph. Chance of rain near 100 percent.

Sunday Night: Mostly cloudy. Breezy. Occasional showers in the evening, then scattered showers after midnight. Lows 61 to 68 in the valleys to around 58 above 4000 feet. East winds 10 to 25 mph. Chance of rain 90 percent.

North Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 63 to 71. East winds up to 15 mph. Chance of rain 50 percent.

Sunday: Mostly cloudy. Scattered showers in the morning, then showers likely in the afternoon. Highs 74 to 85. East winds up to 15 mph. Chance of rain 70 percent.

Sunday Night: Mostly cloudy with scattered showers. Lows 63 to 71. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows 63 to 74. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Sunday: Mostly cloudy with showers likely. Highs 72 to 84. East winds 10 to 15 mph. Chance of rain 70 percent.

Sunday Night: Mostly cloudy. Showers likely in the evening, then scattered showers after midnight. Lows 63 to 74. East winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

High pressure north of the islands will maintain moderate to breezy easterly trade winds through the forecast period. Clouds and showers will favor windward and mauka areas, particularly at night and during the early morning hours, with a few showers occasionally spilling into leeward areas due to the strength of the trades. Some shower development is also expected each afternoon over Kona slopes of the Big Island. A disturbance aloft could bring an increase in shower coverage and intensity late next week.

Discussion

High pressure north of the islands continues to produce moderate to breezy easterly trade winds across the state. Satellite imagery shows partly to mostly cloudy skies across the region this afternoon, with the typical distribution of clouds over windward and mauka areas and the Kona slopes of the Big Island. Radar imagery shows generally dry conditions with isolated to widely scattered showers embedded in the trade wind flow moving into windward coasts and slopes, along with a few showers over leeward slopes of the Big Island.
Guidance continues to show high pressure strengthening as it moves northeastward and further away from the islands tonight through early next week. This will maintain breezy trades across the islands. The trades may ease slightly during the middle to latter part of next week as a couple of fronts pass by to the north of the state. Fairly typical trade wind weather will prevail through most of the forecast period, with showers favoring windward and mauka areas, particularly at night and during the early morning hours A few showers will occasionally spill into leeward areas due to the strength of the trades, and some leeward shower development is expected each afternoon on the Big Island. A disturbance aloft could increase shower coverage and intensity across the islands late next week.

Aviation

Breezy trades will continue into next week resulting in AIRMET Tango in effect for tempo moderate turbulence below 7000 feet for all leeward areas.
Trades will carry in scattered low clouds and showers from the east, which is expected to increase tonight through Sunday morning, bringing possible MVFR ceilings, visibility and brief mountain obscurations. AIRMET Sierra for the mountain obscurations will remain a possibility later on tonight for select windward areas.

Marine

High pressure far north of the state will slightly strengthen through Sunday, which should cause the trade winds to strengthen a notch this evening through Sunday. Thus, a Small Craft Advisory (SCA) is in effect for most Hawaiian Waters through Sunday due to the widespread strong trade winds across the state. Trade winds could weaken slightly early next week, which could cause winds to drop just below SCA thresholds for many areas. SCA will likely continue for the windier waters around Maui County and the Big Island throughout next week.
Surf along south-facing shores continues to trend up this afternoon as a new, long period, south southwest swell continues to fill in. Offshore buoys showed a steady increase this morning and now seems to be leveling off this afternoon with swell heights of 3 to 4 feet at 15 to 16 seconds. This should translate to surf heights peaking just below advisory thresholds overnight with a slow downward trend Sunday afternoon through the middle of next week.
Surf along east-facing shores should see a slight increase of rough and choppy surf due to the trade winds strengthening tonight into Sunday. Rough and choppy surf will persist throughout next week with a slight decrease in surf heights as the trades ease slightly early next week.
Surf along exposed north-facing shores will decline on Sunday as the current short-period north swell fades. A small northwest swell should fill in late Sunday into Monday, which should maintain some small surf along north facing shores through next week.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Sunday for Kauai Northwest Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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