West Kaua’i

Tonight: Mostly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 66 to 71 near the shore to around 59 above 3000 feet. Northeast winds up to 20 mph. Chance of rain 40 percent.

Saturday: Breezy. Mostly sunny with isolated showers. Highs 81 to 87 near the shore to around 69 above 3000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Scattered showers. Lows 66 to 71 near the shore to around 58 above 3000 feet. Northeast winds up to 20 mph increasing to 10 to 20 mph after midnight. Chance of rain 50 percent.

South Kaua’i

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 69. Northeast winds 20 to 25 mph. Chance of rain 40 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs 76 to 84. Northeast winds 20 to 25 mph. Chance of rain 50 percent.

Saturday Night: Breezy. Mostly cloudy with scattered showers. Lows around 69. Northeast winds 15 to 25 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 62 to 67 in the valleys to around 57 above 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Saturday: Mostly cloudy. Breezy. Scattered showers in the morning, then numerous showers in the afternoon. Highs 70 to 79 in the valleys to around 61 above 4000 feet. Northeast winds 10 to 20 mph decreasing to up to 20 mph in the afternoon. Chance of rain 70 percent.

Saturday Night: Mostly cloudy. Breezy. Showers in the evening, then numerous showers after midnight. Lows 62 to 67 in the valleys to around 57 above 4000 feet. East winds up to 20 mph. Chance of rain 90 percent.

North Kaua’i

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 62 to 70. Northeast winds 10 to 20 mph. Chance of rain 60 percent.

Saturday: Partly sunny. Breezy. Scattered showers in the morning, then numerous showers in the afternoon. Highs 74 to 82. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Saturday Night: Mostly cloudy with numerous showers. Lows 62 to 69. East winds 10 to 15 mph. Chance of rain 70 percent.

East Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 62 to 72. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Mostly cloudy. Breezy. Scattered showers in the morning, then numerous showers in the afternoon. Highs 71 to 83. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Saturday Night: Mostly cloudy with numerous showers. Lows 63 to 73. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Breezy trades will focus showers associated with a dissipating front over Oahu and Kauai into Saturday while dry weather and light winds prevail elsewhere. Trades then return to the remainder of the area tonight and continue through next week.

Discussion

Regional observations and model analyses this afternoon reveal a dissipating cold front stalled in the Kauai Channel beneath a mostly opaque canopy of high clouds aloft. Strong southwesterlies aloft ensure high clouds will persist for the remainder of today into tonight helping to tamp down late afternoon temperatures. Radar composite shows the focus of showers associated with said front mainly over the Kauai Channel at press time with isolated activity noted over portions of Windward Oahu as breezy trades make their return to the western end of the state. This band of frontal moisture will favor enhanced showers over windward and mauka sections of Oahu and especially Kauai tonight into tomorrow until building trades usher it west of the state by late Saturday. Elsewhere, breezy trades gradually return as governing high pressure becomes established near 30N. This in turn favors a return to a typical distribution of clouds and showers over windward and mauka areas going forward. Little change then for the remainder of the forecast period as breezy trades prevail.

Aviation

A dissipating front over the western end of the state has stalled across the Kauai Channel with breezy northeasterly trade winds building in its wake. A band of enhanced clouds and showers will persist across the Kauai Channel and portions of Kauai and Oahu through this evening as moisture lingers along the dissipating frontal boundary, then lift back towards Kauai overnight into tomorrow. Periods of MVFR conditions are likely within the heavier showers, with brief periods of IFR possible. As such, AIRMET Sierra remains in effect for mountain obscuration for all of Kauai and north through east sections of Oahu through this evening.
The eastern half of the state will see moderate to locally breezy southeasterly winds through the evening before easterly trade winds return tonight. Overall, VFR conditions will prevail across this end of the state.
AIRMET Tango is in effect for tempo moderate upper level turbulence and is expected to continue through the evening.

Marine

Trade winds will build tonight and become locally strong and gusty during the weekend. A dissipating front stalled in the Kauai Channel will drift westward over Kauai late tonight and Saturday. Meanwhile, strong high pressure far northwest of the state will build and creep eastward. As a result, fresh to locally strong trade winds, which area already observed around Kauai, will develop across the typically windy waters around the Big Island and Maui County tonight and will persist through at least Sunday. A Small Craft Advisory (SCA) remains in effect around Kauai and has been expanded to waters around the Big Island and Maui County. Trades will likely ease slightly Monday and Tuesday as the surface high weakens, but trades are expected to build again by Wednesday.
A north-northwest (330-340 deg) swell will continue to build down the island chain tonight, followed by a large north (340-350 deg) swell Saturday and Sunday. Recent observations from buoy 51001 have shown the new north-northwest swell coming in above guidance, and High Surf Advisory conditions are expected across most north facing shores tonight and early Saturday. A much larger pulse of long period north swell will rapidly build Saturday afternoon and peak Saturday night and Sunday. During the peak, surf along north and exposed east facing shores of most islands will reach High Surf Warning levels, while most west facing shores experience advisory level conditions. Moderate to heavy surges in north facing harbors, mainly at Kahului and Hilo, are anticipated by Saturday and will persist through the weekend. The large swell will also produce combined seas in excess of 10 feet over most waters and will contribute to the need for a SCA. The north swell will steadily decline on Monday and will fade by the middle of next week.
Small surf will prevail along south facing shores through early Sunday. Small pulses of south swell are possible late Sunday and Monday and again midweek.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 PM HST Sunday for Niihau, Oahu North Shore, Olomana, Maui Windward West, Kauai North, Kauai East, Koolau Windward, Molokai Windward, Molokai North, Maui Central Valley North, Windward Haleakala, Big Island East, Big Island North.
High Surf Advisory from 6 AM Saturday to 6 PM HST Sunday for Kauai Leeward, Waianae Coast, Maui Leeward West, Molokai West.
Small Craft Advisory until 6 PM HST Sunday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel.
Small Craft Advisory until 6 PM HST Sunday for Oahu Windward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory from 6 AM Saturday to 6 PM HST Sunday for Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Big Island Windward Waters.

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