West Kaua’i

Tonight: Mostly clear. Isolated showers in the evening. Lows around 73 near the shore to around 64 above 3000 feet. Light winds. Chance of rain 20 percent.

Saturday: Sunny with isolated showers. Highs 85 to 92 near the shore to around 78 above 3000 feet. North winds up to 10 mph shifting to the south in the afternoon. Chance of rain 20 percent.

Saturday Night: Mostly clear. Isolated showers in the evening. Lows around 73 near the shore to around 63 above 3000 feet. Light winds. Chance of rain 20 percent.

South Kaua’i

Tonight: Partly cloudy with isolated showers. Lows 71 to 76. Northeast winds around 10 mph. Chance of rain 20 percent.

Saturday: Mostly sunny with isolated showers. Highs 79 to 90. East winds 10 to 15 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy with isolated showers. Lows around 73. Northeast winds around 10 mph. Chance of rain 20 percent.

Kaua’i Mountains

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows around 69 in the valleys to around 61 above 4000 feet. Light winds. Chance of rain 50 percent.

Saturday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 76 to 83 in the valleys to around 70 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Saturday Night: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows around 68 in the valleys to around 61 above 4000 feet. East winds around 10 mph. Chance of rain 40 percent.

North Kaua’i

Tonight: Partly cloudy with isolated showers. Lows 65 to 75. Southeast winds up to 10 mph. Chance of rain 20 percent.

Saturday: Mostly sunny with isolated showers. Highs 73 to 86. East winds up to 15 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy with isolated showers. Lows 64 to 75. East winds around 10 mph. Chance of rain 20 percent.

East Kaua’i

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 68 to 76. Northeast winds up to 10 mph. Chance of rain 40 percent.

Saturday: Mostly sunny with isolated showers. Highs 79 to 87. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Saturday Night: Partly cloudy with isolated showers. Lows 67 to 75. East winds around 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light to moderate east-southeasterly winds will persist through Saturday before taking on a slight northeasterly component on Sunday. This lighter flow will allow for a daily sea and land breeze cycle that will bring clouds and a few showers to leeward and interior areas each afternoon and clearing overnight. Monday through midweek, trade winds will strengthen to moderate to breezy levels, bringing a return to more consistent windward showers.

Discussion

Light to moderate east-southeast winds continue to fill in across the state this afternoon as a weak surface trough pushes further northwest of Kauai. Surface observations show onshore sea breezes across much of the state, with radar and satellite imagery reflecting this as they show clouds and a few showers building up over leeward and interior areas.
Light to moderate east-southeast winds will continue through Saturday before the approach of a front/trough from the northwest causes the weak background flow to back out of the east-northeast on Sunday. Despite the slight variation in wind direction, the light to moderate background flow will bring a combination of windward and mauka showers along with sea breeze induced leeward and interior showers through the weekend. Overall, shower activity should become limited as drier air filters in. However, a plume of deeper moisture passing just to the south of the Big Island may bring an uptick in showers along the Big Islands windward and southeast facing slopes tonight through Saturday. In addition, dew points are expected to remain in the 70s for many locations across the state through Saturday, maintaining muggy conditions through much of the weekend.
Heading into next week, the subtropical high to the far northeast will gradually regain control, allowing easterly trades to build to moderate to breezy speeds by Wednesday. This will usher in slightly lower dew points, and combined with the breezier trades, some relief from the mugginess. Aloft, model guidance continues to show an upper level low pinching off of a longwave trough to the far north and moving toward the state from the northeast. There still remains some variance between the global models on where this upper level low tracks, but as it nears by midweek, it may enhance trade wind showers as batches of moisture roll through.

Aviation

A rather stable, gentle to moderate easterly trade wind flow will prevail through the weekend. MVFR ceilings will periodically develop along windward slopes, while afternoon sea breezes produce higher ceilings and isolated SHRA over terrain. VFR should dominate at the terminals, and no AIRMETs are in effect.

Marine

Light to moderate trades will hold for the next couple of days as a weak surface ridge remains northeast of the area and front passes north. Trade winds will begin to increase Monday and trend upward through next week the front dissipates the ridge strengthens north of island chain.
A small, medium period south swell will continue to steadily fade into Saturday, allowing surf along south and west-facing shores to drop a notch. A series of small, medium to long period south and southeast swells will fill in Saturday into the first half of next week, which will boost surf heights back near seasonal averages through next week.
Tiny surf will prevail along north-facing shores through most of the coming week as only some limited short-period energy reaches the islands from the north. Trade winds remain lighter than normal through the weekend, keeping surf along east-facing shores below average. East shore surf will begin to trend up early next week as trade winds increase upstream and across the region.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov