West Kaua’i

Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows around 71 near the shore to around 60 above 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Thursday: Mostly sunny in the morning then becoming partly sunny. Breezy. Isolated showers. Highs around 80 near the shore to around 68 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Thursday Night: Partly cloudy with isolated showers. Lows around 69 near the shore to around 58 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 67 to 72. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Thursday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 79. Northeast winds 15 to 20 mph. Chance of rain 70 percent.

Thursday Night: Mostly cloudy with scattered showers. Lows 65 to 70. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then occasional showers after midnight. Lows 60 to 65 in the valleys to around 54 above 4000 feet. East winds 10 to 25 mph. Chance of rain 90 percent.

Thursday: Mostly cloudy. Breezy. Occasional showers in the morning, then numerous showers in the afternoon. Highs 67 to 75 in the valleys to around 62 above 4000 feet. East winds 10 to 20 mph. Chance of rain 90 percent.

Thursday Night: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 58 to 63 in the valleys to around 52 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

North Kaua’i

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 63 to 72. East winds up to 20 mph. Chance of rain 50 percent.

Thursday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 72 to 79. East winds up to 15 mph. Chance of rain 70 percent.

Thursday Night: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 61 to 70. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 61 to 73. East winds 10 to 15 mph. Chance of rain 70 percent.

Thursday: Mostly cloudy. Occasional showers in the morning, then numerous showers in the afternoon. Highs 72 to 79. East winds 10 to 15 mph. Chance of rain 90 percent.

Thursday Night: Mostly cloudy with scattered showers. Lows 59 to 71. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Breezy to locally windy trades will continue through the week. Showers will favor windward areas, and some will briefly pass over leeward communities on the gusty winds. Bands of moisture within the trades will bring periods of increased rainfall.

Discussion

Breezy to locally windy trades will persist into tonight. The trades are being driven by a strong 1035 mb surface high centered nearly 1100 miles northeast of the state. A disturbance aloft continues to keep the inversion somewhat weak and elevated, but a mid-level ridge over the region remains strong enough to produce some stability. As a result, winds continue to be enhanced over and downwind of terrain, especially on the Big Island, Maui, and Lanai where a Wind Advisory is in place. The surface high will begin to gradually weaken and creep eastward tonight, leading to slightly easing winds. However, given the strength of the winds this afternoon, the Wind Advisory has been extended through the night to account for downsloping winds that tend to be prevalent during the evening. A rather typical pattern of mainly windward showers, with a few briefly spreading leeward, will persist. A band of shallow moisture in the trades will fuel more frequent showers near Kauai and Oahu, while drier conditions are expected farther south, especially on the Big Island.
An extended period of trade winds will continue through at least the middle of next week. Trades will ease to moderate to locally breezy levels late Thursday as the above mentioned surface high is pushed eastward. However, winds will ramp up again late Saturday as another strong surface high develops north of the islands. The area of moisture currently affecting the state will move off to the west on Thursday, which may lead to a slight decrease in shower activity Friday and Saturday. Another band of moisture will likely pass over the islands Sunday and Monday and produce an increase in mainly windward shower activity.

Aviation

Breezy to locally windy trade winds will continue to blow across the state through at least tonight, with a slight decrease in wind speeds tomorrow. Periods of clouds and showers remain in the forecast, favoring the windward and mountain areas in the overnight to early morning hours. Brief periods of MVFR ceilings and visibility will be possible in showers.
AIRMET TANGO remains in effect for moderate low level turbulence below 8000 feet over and downstream of island mountains due to the breezy to locally windy trade winds. This AIRMET may need to be extended through the next couple of days due to the stronger trade winds.

Marine

Strong to near gale-force easterly trade winds will persist as strong high pressure remains north-northeast of the area. Seas will remain rough, with a combination of short-period wind- generated seas and northwest swells moving through. Small Craft Advisory conditions are expected to continue for all Hawaiian waters through Thursday and may be extended into the weekend due to a combination of winds and seas.
Surf along exposed north and west-facing shores will continue to ease into Thursday as a northwest swell moves out. An upward trend is expected late Thursday through Saturday as a couple of northwest (320-330 degrees) swells arrive, peaking Friday night through Saturday. This may push surf heights back to advisory levels at the peak late Friday through Saturday. A downward trend is then expected Sunday through early next week.
Surf along east-facing shores will remain rough through the rest of the week due to strong easterly trade winds.
Surf along south-facing shores will remain small, with mainly background south and southeast swells.

HFO Watches/Warnings/Advisories

Wind Advisory until 6 AM HST Thursday for Lanai Mauka, Kahoolawe, Maui Windward West, Maui Leeward West, Kohala, Big Island Interior, Molokai, 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 Thursday for all Hawaiian waters.

Kauai Now Weather is brought to you by Blue Hawaiian Helicopters.