West Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 85 to 90 near the shore to around 77 above 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows 69 to 74 near the shore to around 62 above 3000 feet. Northeast winds around 10 mph. Chance of rain 20 percent.

Saturday: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 84 to 90 near the shore to around 76 above 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

South Kaua’i

Today: Mostly cloudy. Occasional showers in the morning, then scattered showers in the afternoon. Highs 80 to 89. East winds 10 to 15 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows around 72. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Saturday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 80 to 88. East winds 10 to 15 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Breezy. Occasional showers. Highs 74 to 84 in the valleys to around 66 above 4000 feet. East winds 10 to 20 mph. Chance of rain near 100 percent.

Tonight: Breezy. Occasional showers in the evening, then numerous showers after midnight. Lows 64 to 70 in the valleys to around 59 above 4000 feet. East winds 10 to 20 mph decreasing to up to 20 mph after midnight. Chance of rain near 100 percent.

Saturday: Breezy. Mostly cloudy with numerous showers. Highs 74 to 84 in the valleys to around 66 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

North Kaua’i

Today: Mostly cloudy with numerous showers. Highs 77 to 87. East winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows 65 to 73. East winds 10 to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Scattered showers in the morning, then numerous showers in the afternoon. Highs 77 to 87. East winds 10 to 15 mph. Chance of rain 70 percent.

East Kaua’i

Today: Occasional showers in the morning, then scattered showers in the afternoon. Highs 73 to 86. East winds 10 to 15 mph. Chance of rain near 100 percent.

Tonight: Mostly cloudy with numerous showers. Lows 63 to 76. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Saturday: Mostly cloudy with scattered showers. Highs 73 to 86. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

High pressure far north and northeast of the state will maintain moderate to locally breezy trades today, with winds starting to weaken over the weekend. Expect to see fairly typical summertime weather into next week as clouds and showers favor windward and mauka areas.

Discussion

A 1033 mb high remains well to the north-northeast of the islands. and will continue to bring moderate to locally breezy trade winds to the region through this afternoon. The high is expected to drift northward over the weekend and into next week, which will allow for a bit of a downtick in winds tonight and tomorrow.
Showery low clouds continue to impact portions of Maui County and Oahu overnight. The backend of this area is expected to reach the islands later this morning. As such, look for improving conditions today. The northern edge is moving over the Kauai Channel, but it remains to be seen if the area holds together enough to impact Kauai.
The high is expected to slowly move north over the weekend, which will help the trades to weaken some. A drier airmass is expected to move in, with limited clouds and showers mainly impacting the north and east sections of the islands.
The one wrinkle to the forecast will be the evolution of an upper level disturbance to the north of the islands. This disturbance could help to enhance instability over the western half of the state which could bring some enhanced showers this weekend and early next week.

Aviation

High pressure to the northeast will maintain fresh to locally strong trade winds that will persist today, with a slight downward trend tonight and tomorrow. AIRMET Tango is in effect for moderate turbulence below 8000 feet to the lee of mountains for all Hawaiian islands, due to winds and the stable atmosphere.
An area of low clouds and showers has been impacting Maui County and Oahu overnight, prompting AIRMET Sierra for tempo mountain obscurations above 2500 feet along windward sides of Maui, Molokai and Oahu. This area has nudged northward overnight into the Kauai Channel, but has also thinned. Its questionable whether or not Kauai will need an AIRMET Sierra later today. Expect conditions to improve across Maui County and Oahu today. Prevailing VFR conditions expected for Big Island.

Marine

High pressure far northeast of the waters will continue to drive moderate to locally strong trade winds through the day. A Small Craft Advisory remains in effect for the typical windy waters around Maui County and Big Island through this afternoon. There will be a short-lived lull in trade speeds early Saturday as the pressure gradient from the high northeast of the state relaxes a bit. While the high will pull away further to the north early next week, the gradient will remain tight enough across the nearshore waters to result several more days of moderate to locally strong trades.
The recent small, long period south swell will continue its gradual decline through the day. A reinforcing longer period south swell is scheduled to arrive tonight. This little boost, in tandem with another small, long period south swell arriving Sunday night into Monday, will hold south-facing shore surf to slightly under summertime averages. East-facing shore surf will remain rough as moderate to fresh trades blow through the day. A very small northwest swell originating behind a front hanging up far northwest of the islands may pass through early next week. This will keep north-facing shore surf from going completely flat.

HFO Watches/Warnings/Advisories

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