West Side

Tonight: Partly cloudy. Isolated showers in the evening. Lows 63 to 70. East winds up to 10 mph. Chance of rain 20 percent.

Tuesday: Sunny. Highs around 78. East winds up to 10 mph.

Tuesday Night: Mostly clear. Lows 64 to 70. Northeast winds up to 10 mph in the evening becoming light.

South Side

Tonight: Mostly clear. Lows 62 to 72. North winds up to 10 mph.

Tuesday: Sunny. Highs around 84. North winds up to 10 mph.

Tuesday Night: Mostly clear. Lows 62 to 72. Light winds.

North Shore

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 67 near the shore to around 49 near 5000 feet. Southeast winds up to 10 mph. Chance of rain 40 percent.

Tuesday: Mostly sunny with isolated showers. Highs 76 to 81 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tuesday Night: Partly cloudy with isolated showers. Lows around 67 near the shore to around 49 near 5000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Central Maui

Tonight: Mostly clear. Lows 62 to 67. Northeast winds up to 10 mph.

Tuesday: Sunny. Highs 79 to 85. Northeast winds up to 15 mph.

Tuesday Night: Mostly clear. Lows around 65. Light winds.

Upcountry

Tonight: Mostly clear. Scattered showers in the evening, then isolated showers after midnight. Lows 40 to 52. Light winds becoming east up to 10 mph after midnight. Chance of rain 30 percent.

Tuesday: Sunny. Isolated showers in the morning. Highs around 61 at the visitor center to around 64 at the summit. East winds up to 10 mph. Chance of rain 20 percent.

Tuesday Night: Mostly clear. Lows 41 to 52. Light winds becoming southeast up to 10 mph after midnight.

East Maui

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 67 near the shore to around 49 near 5000 feet. Southeast winds up to 10 mph. Chance of rain 40 percent.

Tuesday: Mostly sunny with isolated showers. Highs 76 to 81 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tuesday Night: Partly cloudy with isolated showers. Lows around 67 near the shore to around 49 near 5000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Lanai City

Tonight: Mostly clear. Lows around 62. Northeast winds up to 10 mph.

Tuesday: Mostly sunny. Isolated showers in the afternoon. Highs 71 to 78. Light winds. Chance of rain 20 percent.

Tuesday Night: Mostly clear. Lows around 62. Light winds becoming southeast up to 10 mph after midnight.

Kaunakakai

Tonight: Partly cloudy with isolated showers. Lows 54 to 70. East winds up to 10 mph. Chance of rain 20 percent.

Tuesday: Sunny. Isolated showers in the morning. Highs 69 to 84. East winds up to 10 mph. Chance of rain 20 percent.

Tuesday Night: Mostly clear. Lows 54 to 70. Light winds.

Detailed Forecast

Synopsis

Light to occasionally moderate east to southeasterly winds are anticipated to progress through the week and into the weekend, favorable for light showers and cloud cover across windward areas overnight and leeward and interior areas in the afternoon associated with sea breeze development.

Discussion

Latest observations show widespread sea breeze activity across the state is diminishing as land breezes have developed within a light to moderate east to southeasterly background flow. Grids have been updated to show shower activity easing through the evening and early morning hours as an upper- level ridge builds to the 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

A front stalled north of the region will help to maintain east southeasterly winds tonight, before veering southeast and strengthening Tuesday as a low moves far northwest of the islands. This relatively light winds should lead to drainage flow tonight followed by sea breezes along coastal areas on Tuesday.
Isolated showers may develop over the interior Tuesday afternoon. VFR conditions elsewhere.
No AIRMETs are currently in effect.

Marine

A dissipating stationary front just northwest of Kauai and a weak surface high to the east of the islands will maintain a fairly slack pressure gradient across the state. This will result in gentle to moderate east to east southeast winds through Tuesday night. 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 middle of the week. Surface high pressure positioned northeast of the islands will remain the main driver to primarily light to gentle east southeast breezes the remainder of the week. Once the ongoing passage of this large northwest swell subsides through Tuesday, seas will return to average 4 to 5 foot heights the next several days.
Tonight's unseasonably large to moderate size, medium period northwest (320-330 degree) swell peaked today and will fall through Tuesday. The High Surf Advisory (HSA) will be in effect for the smaller island north-facing shores and all island west- facing shores (except Maui) through Tuesday afternoon to account for this slow declining swell. The HSA for Big Island west-facing shores is also in effect through Tuesday afternoon as westerly swell that has sneaked into these shores falls below 5 feet. A Small Craft Advisory is in effect through early Tuesday morning to account for this passing swell supporting 10 foot significant wave heights. 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 may provide a small bump to southern shore surf Thursday and/or Friday.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Tuesday for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kona, Kohala, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.
Small Craft Advisory until 6 AM HST Tuesday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Kaiwi Channel, Maui County Windward Waters.

Data Courtesy of NOAA.gov