Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82 near the shore to around 72 above 3000 feet. East winds up to 25 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows around 72 near the shore to around 62 above 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Saturday: Breezy. Mostly sunny with isolated showers. Highs around 82 near the shore to around 72 above 3000 feet. East winds up to 25 mph. Chance of rain 20 percent.

South Kaua’i

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

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 69 to 75. Northeast winds 15 to 25 mph. Chance of rain 50 percent.

Saturday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 80. East winds 15 to 25 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 71 to 76 in the valleys to around 63 above 4000 feet. East winds 10 to 25 mph. Chance of rain 80 percent.

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then frequent showers after midnight. Lows 62 to 67 in the valleys to around 56 above 4000 feet. East winds 10 to 25 mph. Chance of rain 80 percent.

Saturday: Mostly cloudy. Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 71 to 76 in the valleys to around 63 above 4000 feet. East winds 10 to 25 mph. Chance of rain 80 percent.

North Kaua’i

Today: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 71 to 81. 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 65 to 72. East winds up to 20 mph. Chance of rain 70 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs 71 to 81. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

East Kaua’i

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 72 to 81. 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 63 to 75. East winds 10 to 20 mph. Chance of rain 70 percent.

Saturday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 72 to 81. East winds 10 to 20 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Breezy to locally windy easterly trades are here to stay, potentially through early next week as high pressure remains positioned to the north. The best chance for showers will favor the typical windward and mauka locations overnight through the early morning hours each day as pockets of moisture move through. Trades will gradually ease around the midweek time frame as a cold front passes to the north.

Discussion

Guidance remains in good agreement and depicts the gusty easterly trades holding through early next week as strong high pressure remains anchored to the north. The upper low and surface trough that are supporting the thunderstorm activity a few hundred miles west of Kauai this morning will continue to drift westward and away from the area through the weekend. Mostly stable and dry conditions will be the result, with the best chance for showers favoring windward and mauka locations overnight through the morning hours as pockets of moisture move through. Peak wind speeds in the typically windier locations will hover around the wind advisory threshold of 30 mph over the next couple of days.
For the extended period (Tuesday night-Friday), guidance remains in decent agreement and depicts the ridge weakening as an upper trough and its attendant cold front pass to the north. If this materializes, the gradient will weaken and allow the trades to relax beginning around Wednesday, then enough for a land and sea breeze regime to become established by Thursday. Although confidence in the details remain low this far out in time, the tail end of the aforementioned front passing to the north is projected to hangup north of the state through this time. This pattern transition would result in mostly dry conditions prevailing, except for afternoon showers that manage to develop over leeward areas or where sea breezes form.

Aviation

High pressure to the north will maintain locally strong trade winds into the weekend. Clouds and showers will be focused over the windward slopes with this pattern, leading to some brief MVFR conditions. Otherwise, VFR conditions are expected to prevail.
The locally strong trades continue to produce mechanical turbulence to the lee of the mountains of all islands. As a result AIRMET Tango remains in place, and is expected to continue through the weekend.

Marine

High pressure north of the state will keep strong to near Gale force trade winds blowing through at least Saturday. A Small Craft Advisory (SCA) is now in effect for all coastal waters through 6 PM Saturday. This SCA will likely need to be extended for a large chunk of the marine area through the weekend and potentially through early next week. A front approaching from the northwest may ease the trade winds around the middle of next week.
The current long-period south swell will gradually decline over the next few days, however a small reinforcement arriving today will help keep south shore surf elevated into early next week. Surf should drop below the summertime average along south facing shores Tuesday through Thursday.
The current small northwest swell will continue to fade out today, with minimal surf then expected through the middle of next week. A new small medium period northwest swell could give north shore surf a slight boost Thursday.
East shore surf should remain elevated and near seasonal levels through early next week due to the strong trades over and upstream of the islands. A small decline in east shore surf is possible Wednesday and Thursday if the trades ease up as indicated by the latest model guidance.

HFO Watches/Warnings/Advisories

Wind Advisory until 6 PM HST this evening for Lanai Mauka, Kahoolawe, Maui Windward West, Maui Leeward West, Kohala, Big Island Interior, Lanai Windward, Lanai Leeward, Maui Central Valley North, Maui Central Valley South, Windward Haleakala, South Haleakala, Big Island South, Big Island Southeast, Big Island North.
Small Craft Advisory until 6 PM HST Saturday for all Hawaiian waters,

Data Courtesy of NOAA.gov