West Kaua’i

Today: Mostly sunny. Breezy. Scattered showers early in the morning, then isolated showers in the late morning and afternoon. Highs around 81 near the shore to around 69 above 3000 feet. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows around 68 near the shore to around 57 above 3000 feet. Northeast winds 10 to 20 mph decreasing to up to 20 mph after midnight. Chance of rain 20 percent.

Saturday: Breezy. Mostly sunny with isolated showers. Highs around 81 near the shore to around 69 above 3000 feet. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

South Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs around 80. Northeast winds 15 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 64 to 69. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs around 80. Northeast winds 10 to 25 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Numerous showers early in the morning, then scattered showers in the late morning and afternoon. Highs 68 to 76 in the valleys to around 63 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 57 to 62 in the valleys to around 51 above 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Saturday: Mostly cloudy. Breezy. Numerous showers early in the morning, then scattered showers in the late morning and afternoon. Highs 68 to 76 in the valleys to around 63 above 4000 feet. Northeast winds 10 to 25 mph. Chance of rain 70 percent.

North Kaua’i

Today: Partly sunny. Breezy. Numerous showers early in the morning, then scattered showers in the late morning and afternoon. Highs 73 to 80. East winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 60 to 69. East winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs 73 to 80. East winds 10 to 20 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly cloudy. Breezy. Numerous showers early in the morning, then scattered showers in the late morning and afternoon. Highs 73 to 80. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 58 to 70. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Breezy. Mostly cloudy with scattered showers. Highs 73 to 80. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Breezy to windy trade winds will persist through early next week, bringing periods of windward and mauka showers as bands of moisture move through.

Discussion

Model guidance remains in decent agreement, showing a strong low- to mid-level ridge anchored north of the islands holding firm into next week. This pattern will support a breezy to locally windy trade wind pattern across the state. A weak upper trough nearby will keep the inversion weak and slightly elevated, allowing for occasional increases in windward showers as shallow bands of moisture move through.
One such moisture band is impacting the islands this morning, as shown on satellite/radar, and has led to an uptick in windward and mauka showers. These showers will generally be brief but could produce localized heavy downpours at times. Some showers may also drift over leeward areas of the smaller islands with the breezy trades and weakened/lifted inversion. Conditions should improve later today as some drier air fills in following this band of moisture.
Trade winds will begin to strengthen again over the weekend as a stronger high builds north of the state in the wake of a cold front passing to north. By Sunday, more widespread windy trades are expected, with the potential for advisory-level winds in typically windier areas of Maui County and the Big Island.
Looking ahead to next week, trades will remain strong with a robust high positioned north of the islands. The remnants of the front passing north of the state are expected to settle southward into the islands early next week, bringing another period of wet and windy conditions.

Aviation

Breezy trade winds will prevail during the next 24 hours, with the strongest winds occurring from mid morning through late afternoon. A band of low clouds and showers will move through the islands early this morning, bringing some MVFR cigs and vsbys with it as it moves through, particularly windward and mauka. Once this band moves through, much drier weather will follow, with VFR prevailing through this evening.
AIRMET Sierra is now in effect for mountain obscuration across north through east facing sections of Kauai, Oahu, Molokai, Maui and the Big Island. Conditions should improve later this morning.
AIRMET TANGO remains in effect for moderate low-level turbulence over and downwind of the terrain of all islands. This AIRMET will likely remain in place through the middle of next week.

Marine

Persistent fresh to locally strong trade winds are a result of a tight pressure gradient lying across the state. Large high pressure located approximately 1,100 miles northeast of the islands will maintain this tight pressure gradient into the weekend. a slow easterly movement of the high into early next week will keep the gradient tight enough to support amped up trades well into next week. The passage of a series of moderate size northwest swells and days of these stronger trades will maintain wind-driven waves and rough seas. An all-water Small Craft Advisory will be in effect for the near future due to this combination of strong winds and elevated seas.
Surf along north and west-facing shores will pick up through the day as a somewhat large northwest (310-330 degree), longer period swell moves around the island chain. This swell may push surf heights to advisory levels as it peaks from late tonight into early Saturday morning. This swell will then begin to fall from late Saturday through early next week.
Surf along east-facing shores will remain rough into next week due to this persistent fresh to locally strong trade flow over and upstream of the islands.
Surf along south-facing shores will remain small as mainly background south and southeast swells pass around the state the next several days.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Saturday for all Hawaiian waters,