West Kaua’i

Rest Of Tonight: Mostly clear. Lows around 70 near the shore to around 60 above 3000 feet. Northeast winds up to 15 mph.

Friday: Sunny and breezy. Highs 83 to 88 near the shore to around 75 above 3000 feet. East winds up to 20 mph.

Friday Night: Partly cloudy. Breezy. Isolated showers after midnight. Lows around 70 near the shore to around 61 above 3000 feet. East winds up to 20 mph becoming 10 to 15 mph after midnight. Chance of rain 20 percent.

South Kaua’i

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

Friday: Breezy. Mostly sunny with isolated showers. Highs 80 to 87. East winds 10 to 20 mph. Chance of rain 20 percent.

Friday Night: Breezy. Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 71. Northeast winds 10 to 20 mph. Chance of rain 40 percent.

Kaua’i Mountains

Rest Of Tonight: Partly cloudy with scattered showers. Lows 61 to 69 in the valleys to around 58 above 4000 feet. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 40 percent.

Friday: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs 75 to 81 in the valleys to around 65 above 4000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 40 percent.

Friday Night: Breezy. Mostly cloudy with scattered showers. Lows 61 to 69 in the valleys to around 58 above 4000 feet. East winds up to 20 mph. Chance of rain 40 percent.

North Kaua’i

Rest Of Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 63 to 71. East winds up to 15 mph shifting to the southeast after midnight. Chance of rain 30 percent.

Friday: Breezy. Mostly sunny with isolated showers. Highs 76 to 85. East winds up to 20 mph. Chance of rain 20 percent.

Friday Night: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows 64 to 71. East winds up to 15 mph shifting to the southeast after midnight. Chance of rain 20 percent.

East Kaua’i

Rest Of Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 64 to 74. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Friday: Mostly sunny with isolated showers. Highs 73 to 85. East winds 10 to 15 mph. Chance of rain 20 percent.

Friday Night: Mostly cloudy with scattered showers. Lows 64 to 74. East winds 10 to 15 mph. Chance of rain 40 percent.

Detailed Forecast

Synopsis

Breezy trade winds will persist through the remainder of this week into next week, gradually increasing in strength toward the latter half of next week. Brief showers will favor windward and mountain areas, with leeward areas remaining mostly dry, apart from a few isolated showers at night.

Discussion

Trade winds prevail across the islands, increasing in strength over the upcoming weekend and into next week. A 1030 mb broad area of high pressure will persist northwest of the islands, moving eastward through the next several days, with an elongated frontal passage in its wake. This may result in a subtle veering wind direction to a more east-southeast direction late Saturday. Winds will revert back to a primarily eastern direction by Monday, strengthening by mid-week.
By next week, a new, strong high will propagate eastward north of the islands. The aforementioned frontal passage is expected to weaken as it gets overrun by the established trades. Clouds and showers will favor windward and mountain areas, especially during the overnight and early morning hours. Conversely, limited rainfall will be expected on leeward areas apart from a few isolated showers during the night, foreshadowing the beginning of the dry season. Aside from all this, leeward areas of the Big Island will continue to expect clouds and showers each afternoon, diminishing by the overnight hours.

Aviation

Moderate trades through the forecast period. Low cigs and SHRA expected over windward and mauka locations. MVFR conds possible in SHRA but otherwise VFR prevails.
No other AIRMETs are in effect.

Marine

High pressure north of the islands continues to bring moderate to locally strong trade winds to the region, and those winds are expected to continue through the weekend as the high moves to the northeast of the islands. A Small Craft Advisory (SCA) is in effect for the typical windier waters near Maui County and the Big Island, and that is expected to remain in place into next week.
The current moderate to long period north-northwest swell will peak tonight and then slowly decline this weekend. A series of northwest to north swells are expected next week that should produce near or above seasonal average surf.
A small, long period south swell that peaked today will linger into Saturday. This swell will result in above summer average surf heights before slowly subsiding early next week. A mix of both a reinforcing south southwest swell and new long period south southeast swell energy this weekend should maintain near to above seasonal average surf. South-facing shore surf will generally decline next week, but smaller south southwest swells will hold surf at near summer averages through the middle of next week.
As the trades pick up a bit on Friday, expect a bit of an uptick in the easterly wind wave chop, which will continue through the weekend.

HFO Watches/Warnings/Advisories

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

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