Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Mostly sunny with isolated showers. Highs 86 to 92 near the shore to around 77 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 72 near the shore to around 63 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Friday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 87 to 92 near the shore to around 78 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 84 to 90. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows 71 to 76. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Friday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 85 to 91. East winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Partly sunny with scattered showers. Highs 75 to 85 in the valleys to around 67 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Scattered showers in the evening, then occasional showers after midnight. Lows 66 to 71 in the valleys to around 61 above 4000 feet. East winds up to 15 mph. Chance of rain near 100 percent.

Friday: Occasional showers in the morning, then scattered showers in the afternoon. Highs 76 to 86 in the valleys to around 68 above 4000 feet. East winds up to 15 mph. Chance of rain near 100 percent.

North Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 78 to 89. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows 67 to 75. Southeast winds up to 10 mph. Chance of rain 70 percent.

Friday: Partly sunny with scattered showers. Highs 79 to 89. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 76 to 88. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Scattered showers in the evening, then occasional showers after midnight. Lows 66 to 78. Northeast winds up to 10 mph. Chance of rain near 100 percent.

Friday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 76 to 89. East winds up to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Breezy trade winds will continue through the rest of the work week as high pressure remains far to the northeast of the islands. Trades will gradually weaken as the high drifts northeast over the weekend. An upper trough developing over the islands will enhance showers Friday through early next week. Trades will gradually veer southeast early next week as a ridge drifts over the state. Light to gentle southeast flow will promote land- seabreeze pattern with afternoon interior convection through much of next week.

Discussion

A nearly stationary surface high located roughly 1100 miles northeast of the state is generating locally breezy easterly trade winds across the islands. Latest satellite and radar imagery show scattered to isolated clouds and showers focused along windward and mauka regions. Typical tradewind diurnal pattern is expected to continue with clouds and showers easing along windward areas this afternoon, except for Kona slopes which will see and increase in clouds and showers.
The high far northeast of the main Hawaiian Islands will remain nearly stationary through Friday before slowly moving northeast, further away from the state this weekend. As a result, the locally breezy trades will persist through Friday, followed by a gradual reduction in speeds from Saturday onward. Expect a continuation of typical trade wind showers through the weekend, favoring windward and mauka areas, particularly during the overnight and morning hours. A shower or two could make it to leeward sections on the smaller islands, especially Friday through the weekend.
Starting Friday, moisture associated with the remnants of former Tropical Depression 14E will begin to move into the island chain. Upper troughing will move in at about the same time, resulting in an increase in shower coverage and intensity Friday through as late as Sunday night. Although isolated thunderstorms still cannot be ruled out over the coastal waters near the western end of the state, latest models have backed off of this potential slightly from previous runs. Given that it is still a few days out, we will continue to fine tune the details over the next several days.
A low pressure system far to the northwest will start to push the associated ridge axis of the surface high southward towards the main Hawaiian Islands, potentially reaching the state by next Tuesday. Trade winds will gradually become light to gentle, then veer out of the southeast as early as Monday night through much of next week. This pattern will allow development of daytime sea breezes and nighttime land breezes. Although the state will be in an drier airmass, expect a hybrid or convective shower pattern, featuring localized afternoon interior showers along with a few across windward and mauka areas.

Aviation

Moderate to breezy trades will remain in place through the next several days. Clouds and showers will primarily focus over windward and mountain areas and will be greatest in coverage and intensity during the night time and early morning hours. Pockets of MVFR ceilings and visibility can be observed in the heavier showers.
AIRMET Tango remains in effect for tempo moderate turbulence below 9000 feet for areas downwind (south through west) of island terrain. This AIRMET will likely remain in effect through the next few days.
AIRMET Sierra for mountain obscuration will likely continue for portions of the Big Island and Maui, and could spread to the other islands later today.

Marine

A ridge far north of the main Hawaiian Islands will keep fresh to locally strong trade winds in the forecast through Saturday. The ridge will weaken and wind speeds will decrease on Sunday as a low deepens northwest of the islands. Winds will shift to southeasterlies from Monday onward. A Small Craft Advisory (SCA) remains in effect for windier waters around Maui and the Big Island through Friday, but may be extended into Saturday.
Surf along south facing shores will continue to slowly decline as the current small south swell eases. Background swells are expected through the weekend.
Small surf along north facing shores will continue today due to a short-period north-northeast swell. A similar size north- northeast swell is expected to arrive Thursday night and Friday. A slightly larger, mid-period north-northwest swell is expected late Sunday through the middle of next week.
Surf along east facing shores will continue to remain rough and choppy through the weekend, trending down early next week as wind speeds taper off.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Friday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov