West Kaua’i

Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 85 to 91 near the shore to around 77 above 3000 feet. East winds up to 10 mph. Chance of rain 40 percent.

Tonight: Mostly clear with isolated showers. Lows 69 to 74 near the shore to around 62 above 3000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs 85 to 90 near the shore to around 77 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny with scattered showers. Highs 80 to 88. Northeast winds around 10 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers. Lows 70 to 75. Northeast winds around 10 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 80 to 88. East winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Partly sunny with scattered showers. Highs 74 to 84 in the valleys to around 66 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 70 in the valleys to around 59 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 74 to 84 in the valleys to around 66 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

North Kaua’i

Today: Partly sunny with scattered showers. Highs 77 to 88. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 65 to 74. East winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 76 to 87. East winds up to 15 mph. Chance of rain 40 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 72 to 85. Northeast winds around 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 76. Northeast winds up to 10 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 73 to 85. East winds around 10 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

Detailed Forecast

Synopsis

High pressure far northeast of the state will maintain moderate to locally breezy trades through the week. Expect fairly typical summertime weather with clouds and showers favoring windward and mauka areas.

Discussion

Currently, satellite imagery shows small bands of moisture embedded in the trades with clouds moving into windward and mauka areas. Radar imagery shows showers across the area which are expected to continue into the early morning hours.
A high pressure is parked well to the northeast of the state. This high is expected to be in place until Sunday when it will drift off to the north. Due to this high, moderate to breezy trades should continue through Saturday. Once the high starts drifting away trades should weaken a bit.
While an organized source of moisture upstream is lacking with a dry and stable airmass overhead we can expect typical summertime showers and clouds to favor windward and mauka slopes through the forecast period.

Aviation

Moderate to locally breezy trades will persist for the next couple of days. Low cigs and SHRA should mainly be focused over windward and mauka locations. MVFR conds possible in SHRA, otherwise VFR prevails.
AIRMET Sierra is in effect for mtn obsc for windward portions of all of the smaller islands.
AIRMET Tango is in effect for low level turb downwind of island terrain.

Marine

High pressure far northeast of the waters will drive moderate to locally strong trade winds. The Small Craft Advisory that is in effect for the typical windy waters around Maui County and Big Island has been extended through Friday afternoon. Trades may slightly weaken early next week as the high moves further away to the north.
The recent small, long period south swell will continue its decline through the day. A reinforcing longer period south swell is scheduled to arrive Friday night. This little boost, in tandem with another small, long period south swell arriving Sunday night into Monday, will hold south-facing shore surf to summer averages (~5 to 6 ft in higher sets). East-facing shore surf will remain rough as moderate to fresh trades blow the remainder of the week. A very small northwest swell originating behind a front hanging up far northwest of the islands may pass through early next week.

Fire weather

Moderate to locally breezy trade winds will continue through the next several days. Afternoon relative humidity should be near summertime normals. Expect typical summertime fire weather conditions into next week.

HFO Watches/Warnings/Advisories

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