West Kaua’i

Today: Sunny. Isolated showers in the afternoon. Highs 79 to 86 near the shore to around 73 above 3000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear with isolated showers. Lows 65 to 70 near the shore to around 58 above 3000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Sunny with isolated showers. Highs 79 to 86 near the shore to around 72 above 3000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

South Kaua’i

Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 79 to 85. East winds 10 to 15 mph. Chance of rain 30 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 68. Light winds. Chance of rain 30 percent.

Wednesday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 86. Southeast winds up to 10 mph. Chance of rain 30 percent.

Kaua’i Mountains

Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 74 to 80 in the valleys to around 64 above 4000 feet. Southeast winds up to 10 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with scattered showers. Lows 59 to 67 in the valleys to around 56 above 4000 feet. Light winds. Chance of rain 40 percent.

Wednesday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 74 to 81 in the valleys to around 64 above 4000 feet. South winds up to 10 mph. Chance of rain 40 percent.

North Kaua’i

Today: Sunny. Isolated showers in the afternoon. Highs 75 to 82. Southeast winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 61 to 68. Southeast winds up to 10 mph. Chance of rain 30 percent.

Wednesday: Mostly sunny with isolated showers. Highs 75 to 83. South winds up to 10 mph. Chance of rain 20 percent.

East Kaua’i

Today: Mostly sunny with isolated showers. Highs 72 to 84. Southeast winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 61 to 72. South winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Wednesday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 73 to 84. South winds up to 15 mph. Chance of rain 30 percent.

Detailed Forecast

Synopsis

Light to occasionally moderate east to southeasterly winds are expected to persist through the remainder of the week and into the weekend, favorable for light showers across windward areas during the overnight hours and leeward and interior areas during the afternoon hours associated with seas breeze development. Overall shower activity will be limited. A upper-level low will make way to the vicinity of the islands early next week, though confidence remains low at this time with regards to the strength and positioning of the low.

Discussion

Land breezes have developed within a light to moderate east to southeasterly background flow, with shower activity easing through the evening and early morning hours as an upper-level ridge builds east of the islands, increasing overall stability while propagating drier air westward. Meanwhile, a stationary front just north of Kauai will continue to linger and dissipate.
Southeasterly winds will strengthen slightly over the next few days as the pressure gradient between the broad upper-level high to the far northeast of the islands and an incoming frontal passage from the west as a part of a more progressive pattern. While some showers will still be carried into windward areas on the east to southeast winds, the lighter flow will allow sea breezes to bring cloud buildups and a few showers to leeward and interior areas each afternoon, and land breezes to help clear out leeward and interior areas overnight.
Toward the latter end of the week and into the weekend, the light trade wind pattern returns, and with it, light shower activity to the windward aspects of most islands and maintaining this pattern throughout the weekend. Thereafter, the confidence decreases as the latest model guidance diverges as the strength and positioning of a progged low west-northwest of the islands. Evolution of the aforementioned low may play a factor in local wind speeds and direction, however, currently no major impacts are expected at this time.

Aviation

Light to moderate east southeast flow will prevail today as a weak front stalls/dissipates north of the area and a low develops well to the northwest of the island chain. Due to the light flow pattern, expect drainage flow through early this morning followed by sea breezes along coastal locations late this morning into the afternoon.
Isolated showers may develop over the interior this afternoon. VFR conditions elsewhere.
No AIRMETs are currently in effect.

Marine

A dissipating stationary front over the far north offshore waters along with a weak surface high to the east of the islands will maintain a fairly slack pressure gradient across the local waters. This will result in gentle to moderate east to southeast winds through tonight. A developing low far northwest of the islands near the International Date Line will pull further back to the northwest. As this occurs, a front extending east the low will generally veer gentle easterlies more southeasterly through the Wednesday. Surface high pressure positioned northeast of the islands will remain the main driver of primarily light to gentle east southeast breezes the remainder of the week.
The moderate size, medium period northwest (320-330 degree) swell that peaked yesterday will be gradually falling off through the day. The High Surf Advisory remains in effect for the smaller island north-facing and west-facing shores (except Maui) through the afternoon to account for this slow declining swell. A small, medium period north (350-010 degree) swell is expected to arrive on the heels of this fading northwest-north swell Thursday. This north swell is forecast to peak on Friday then ease over the weekend.
South-facing shore surf will remain seasonably small the next couple of days. A small swell arriving from a series of gale lows passing south of New Zealand will arrive near the end of the week. This additional foot on top of southern background long period swell will provide a small bump to southern shore surf Thursday and/or Friday.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.