West Kaua’i

Tonight: Breezy. Partly cloudy with isolated showers. Lows 66 to 71 near the shore to around 59 above 3000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Wednesday: Breezy. Mostly sunny with isolated showers. Highs 80 to 86 near the shore to around 72 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy with isolated showers. Lows 66 to 71 near the shore to around 59 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 around 70. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Wednesday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 77 to 85. East winds 15 to 25 mph. Chance of rain 70 percent.

Wednesday Night: Mostly cloudy with scattered showers. Lows around 69. East winds around 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 59 to 69 in the valleys to around 58 above 4000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Wednesday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 72 to 79 in the valleys to around 62 above 4000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Wednesday Night: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 58 to 69 in the valleys to around 57 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

North Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 63 to 70. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Breezy. Partly sunny with scattered showers. Highs 73 to 83. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy with scattered showers. Lows 62 to 69. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 63 to 73. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Wednesday: Breezy. Partly sunny with scattered showers. Highs 70 to 82. East winds 10 to 20 mph. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy with scattered showers. Lows 63 to 72. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Breezy to strong trades will continue through the forecast period bringing a return to a typical distribution of clouds and showers focused mainly over windward and mauka areas. A couple old front may bring an increase in trade wind showers Thursday, and again Sunday through Monday.

Discussion

Currently at the surface, a strong 1037 mb high is centered around 900 miles north-northeast of Honolulu, and is driving breezy to windy trades across the island chain this evening. Infrared satellite imagery shows partly to mostly cloudy conditions across the state. Radar imagery shows scattered showers moving into windward areas, with coverage the highest across Oahu and Maui County. Main short focus remains on the strong winds tonight and Wednesday.
Strong high pressure north of the islands will slowly weaken as it builds eastward during the next couple days. A front will approach from north Friday and Saturday, then push southward through the islands on Sunday as a new strong high builds in behind it. This high will hold in place Monday and Tuesday, with a new strong high replacing it to the northeast of the state by the middle of next week. An extended period of breezy to windy trades can be expected across the island chain through the next week. The winds appear particularly strong through Wednesday, and a Wind Advisory remains in effect for much of Maui County and Big Island through 6 PM Wednesday.
As for the remaining weather details, fairly typical trade wind weather featuring windward and mauka showers along with the occasional leeward spillover should continue through the forecast period. A couple old front may bring an increase in trade wind showers as they move through, with the first moving through on Thursday, and the next in the Sunday through Monday time frame.

Aviation

A strong surface high pressure system north-northeast of the state will slowly drift eastward over the next few days. Breezy to locally strong trade winds will continue to blow across the state through at least Wednesday night. Periods of clouds and showers remain in the forecast, favoring the windward and mountain areas in the overnight to early morning hours. Brief MVFR ceilings and visibility are expected in showers.
AIRMET TANGO remains in effect for moderate low level turbulence below 8000 feet over and downstream of island mountains due to the strong trade winds. This AIRMET will likely be extended for the next several days due to continued strong winds.

Marine

Strong- to near gale-force easterly trade winds will persist through midweek 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 Wednesday night. Although confidence is low, some waters may fall out of the advisory Thursday as an old boundary settles southward into the area and a weakness forms in the surface ridge farther to the north.
Surf along exposed north- and west-facing shores will continue to ease through midweek as a northwest swell moves out. Another upward trend is expected Thursday night 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 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 PM HST Wednesday 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 Wednesday for all Hawaiian waters,

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