Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Highs around 86 near the shore to around 74 above 3000 feet. East winds up to 15 mph shifting to the south in the afternoon.

Tonight: Partly cloudy. Lows 66 to 71 near the shore to around 57 above 3000 feet. Southeast winds up to 10 mph in the evening becoming light.

Thursday: Mostly sunny. Highs around 87 near the shore to around 75 above 3000 feet. Light winds.

South Kaua’i

Today: Mostly sunny. Isolated showers in the morning. Highs around 83. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 64 to 70. East winds around 10 mph in the evening becoming light. Chance of rain 20 percent.

Thursday: Mostly sunny. Highs around 84. Light winds.

Kaua’i Mountains

Today: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 73 to 80 in the valleys to around 64 above 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 57 to 62 in the valleys to around 52 above 4000 feet. Light winds. Chance of rain 20 percent.

Thursday: Mostly sunny. Highs 74 to 81 in the valleys to around 65 above 4000 feet. Light winds.

North Kaua’i

Today: Mostly sunny with isolated showers. Highs 76 to 85. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 60 to 70. East winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Thursday: Mostly sunny. Highs 77 to 86. Light winds.

East Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 76 to 84. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows 58 to 71. East winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Thursday: Partly sunny in the morning then becoming mostly sunny. Highs 77 to 85. Light winds.

Detailed Forecast

Synopsis

A surface ridge will settle southward during the next few days, with moderate trades today becoming light Thursday and Friday with land and sea breezes common across much of the state. The ridge will lift northward this weekend allowing the trades to gradually strengthen, with locally breezy conditions returning for the first half of next week. Very dry conditions will greatly limit shower activity through the weekend, with a slight increase in windward showers expected early next week as the trades strengthen to locally breezy levels.

Discussion

Currently at the surface, a 1024 mb high is centered around 1150 miles northeast of Honolulu, and is moderate trade winds across the island chain. Infrared satellite imagery shows partly to mostly cloudy skies across the state, with cloud coverage the greatest over windward and mauka areas. Radar imagery shows very little rainfall across the state, with nothing more than isolated very light showers affecting windward slopes at coasts from time to time. Main short term focus continues to revolve around trade wind trends during the next several days.
High pressure northeast of the state will gradually weaken and shift eastward during the next few days, with the associated ridge shifting southward to a location just north of Kauai Thursday and Friday. Moderate trades today, will become light Thursday and Friday with land and sea breezes common across much of the state. The ridge will begin to lift northward over the weekend allowing the trades to gradually strengthen, with moderate to locally breezy conditions returning for the first half of next week.
As for the remaining weather details, very stable and dry conditions remain over the island chain, evident in the sharp trade wind inversions, at or below 5 kft at both Hilo and Lihue during the 12z soundings. Little change in the trade wind inversion is expected through the weekend, which will greatly limit shower activity across the entire state. The trade wind inversion will begin to lift early next week, which should bring a slight increase in trade wind showers, while still remaining drier than normal for this time of year.

Aviation

Trade winds will gradually weaken over the next twenty-four to thirty-six hours as the pressure gradient over the Islands relaxes. Bands of clouds and light showers will favor east and northeast facing slopes and coasts. Brief MVFR conditions are to be expected in showers, otherwise VFR conditions will prevail statewide.
Lingering mid-level atmospheric instability will encourage convective showers over interior and upslope portions of the Big Island today in the afternoon and early evening. Stability is expected to increase later in the week as mid level ridging builds over the state.
AIRMET Tango for low level turbulence lee of island terrain remains in effect. This AIRMET will likely be cancelled toward morning as low-level winds decrease.
AIRMET Sierra remains in effect for mountain obscuration for windward sections of Maui, Molokai, and Oahu. Conditions are expected to improve by late morning.

Marine

The ridge of high pressure is slowly sinking southward, and the result is a downward trend to the moderate trade winds. The Small Craft Advisory (SCA) has been cancelled for all Hawaiian waters and looks to remain that way through the end of the week. Trade winds are expected to continue to ease and diminish significantly Thursday and Friday. Increasing moderate trades are expected during the weekend as the ridge lifts northward.
The active south Pacific will continue to generate southerly swells that will pass through the islands through the middle of the month. The current south-southwest swell has started to decline, and a continued gradual decline is expected through Thursday. Another reinforcing south-southwest swell is expected to arrive late Thursday and Friday, that is currently expected to bring south facing shore surf around the seasonal average. A larger swell is expected to move through the islands this coming weekend, which will likely be near or at HSA levels of 10 feet. A potentially even larger swell is looking increasingly likely late next week that would bring surf well above advisory levels.
The current small northwest swell is on the decline as shorter period energy is now moving through the islands. Another small pulse from the northwest is expected to build through the day into Thursday keeping surf elevated. Wind waves for east facing shores will decline today and will diminish significantly after today coinciding with the light winds through the weekend.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov