West Kaua’i

Today: Mostly sunny. Highs around 89 near the shore to around 77 above 3000 feet. North winds up to 10 mph shifting to the southwest in the afternoon.

Tonight: Partly cloudy. Lows around 75 near the shore to around 64 above 3000 feet. Northeast winds up to 10 mph.

Friday: Mostly sunny. Highs around 89 near the shore to around 77 above 3000 feet. East winds up to 15 mph.

South Kaua’i

Today: Partly sunny. Isolated showers in the morning. Highs around 86. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 71 to 76. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Partly sunny. Breezy. Isolated showers in the morning. Highs around 86. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly cloudy with isolated showers. Highs 76 to 83 in the valleys to around 67 above 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 69 in the valleys to around 60 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Friday: Mostly cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 76 to 83 in the valleys to around 67 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

North Kaua’i

Today: Partly sunny with isolated showers. Highs 79 to 88. Southeast winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 67 to 75. Southeast winds up to 10 mph. Chance of rain 20 percent.

Friday: Partly sunny with isolated showers. Highs 79 to 88. East winds up to 15 mph. Chance of rain 20 percent.

East Kaua’i

Today: Partly sunny with isolated showers. Highs 79 to 87. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 65 to 77. Northeast winds up to 10 mph. Chance of rain 20 percent.

Friday: Mostly cloudy with isolated showers. Highs 79 to 87. East winds 10 to 15 mph. Chance of rain 20 percent.

Synopsis

Trade winds will gradually strengthen today and likely become breezy from Friday through early next week as a surface ridge over the islands lifts northward. Expect predominantly dry and stable weather as the trades return, with clouds and showers mainly affecting windward and mauka locations. Increasing moisture combined with a mid-level disturbance moving through could lead to an increase in windward shower coverage from Sunday night through early next week.

Discussion

A transition to a more typical easterly trade wind pattern is expected today through Friday as a surface trough north of Kauai lifts northwestward and a surface ridge over the islands retreats northward. The early morning satellite imagery depicts a couple of north-to-south oriented low cloud bands approaching, likely marking the leading edge of the incoming breezy trades. As these cloud bands move through over the next day or two, shower coverage could periodically increase, particularly across windward and mauka areas. A mostly dry and stable trade wind pattern will follow and persist through the weekend as the ridge remains north of the area.
For the extended period (Sunday night-early next week), guidance shows an area of deeper moisture advancing westward through the area, with PWs climbing to 1.5 to 2 inches (highest over the Big Island). This surge in moisture combined with a mid-level trough moving through could translate to an increase in windward shower coverage, with some briefly making it into leeward locations of the smaller islands due to a weakened/elevated inversion.

Aviation

Moderate to locally breezy trades will return today and persist through the weekend. SHRA and low cigs should mainly be focused over windward and mauka locations. Some brief MVFR conds can be expected in any SHRA. VFR conds should generally prevail.
AIRMET Sierra is in effect for mtn obsc for windward Big Island.

Marine

A weak trough northwest of the main Hawaiian Islands will continue to drift northwest. Light to gentle southeast flow will give way to trade winds which will gradually strengthen into the moderate to fresh range later today and continue through the weekend. Models show winds across waters around Maui County and the Big Island may briefly reach locally strong conditions, and Small Craft Advisories may be needed through the weekend. As high pressure builds northeast of the waters early next week, moderate to locally strong trade winds will return.
Surf along north facing shores will continue to decline as a short to medium-period north swell fades through the end of the week. North shore surf will return to mostly flat levels over the weekend. Surf along east facing shores will rise to near normal levels Friday through the weekend as trade winds return and strengthen. A mix of background southwest and southeast swells will produce small surf over the next few days. A slight uptick is expected from the south south-west this Friday as a small long period swell moves in and holds through the weekend.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov