West Kaua’i

Tonight: Partly cloudy with isolated showers. Lows around 74 near the shore to around 61 above 3000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Sunday: Mostly sunny. Isolated showers in the afternoon. Highs around 89 near the shore to around 76 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Sunday Night: Partly cloudy. Isolated showers after midnight. Lows around 74 near the shore to around 62 above 3000 feet. East winds up to 10 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Mostly cloudy with isolated showers. Lows around 73. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 82 to 90. East winds 10 to 15 mph. Chance of rain 20 percent.

Sunday Night: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 73. Northeast winds around 10 mph. Chance of rain 40 percent.

Kaua’i Mountains

Tonight: Mostly cloudy with isolated showers. Lows 66 to 72 in the valleys to around 59 above 4000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Partly sunny with isolated showers. Highs 77 to 87 in the valleys to 64 to 69 above 4000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Sunday Night: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 67 to 72 in the valleys to around 59 above 4000 feet. East winds around 10 mph. Chance of rain 50 percent.

North Kaua’i

Tonight: Partly cloudy with isolated showers. Lows 66 to 74. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs 80 to 89. East winds up to 15 mph. Chance of rain 20 percent.

Sunday Night: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 66 to 74. East winds around 10 mph. Chance of rain 30 percent.

East Kaua’i

Tonight: Mostly cloudy with isolated showers. Lows 67 to 78. East winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 77 to 88. East winds 10 to 15 mph. Chance of rain 20 percent.

Sunday Night: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 66 to 78. East winds around 10 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

High pressure centered northeast of Hawaii will drive moderate to fresh trade winds with dry and stable weather into next week. An upper trough will drift through the islands from Tuesday to Thursday possibly increasing showers.

Discussion

High pressure centered northeast of Hawaii will drive moderate to fresh trade winds with dry and stable weather into next week. Visible satellite shows cloud build ups over lower slopes on the Big Island, and a few cirrus clouds passing over the state. Otherwise conditions are mostly sunny to partly cloudy with virtually no precipitation observed on radar. The overall pattern will change little through Monday, with the best chance for rainfall and cloud cover over the windward slopes, but accumulations will be light.
A tropical wave will pass south of the state Tuesday through Thursday. Upper level troughing will set up over the state around the same time may act to enhance showers moving in on both the trade wind flow and the far northern periphery of the wave. Clouds and showers will likely increase during this time frame focusing over windward and mauka areas. The upper trough may become an upper low and deepen next weekend possibly further enhancing rainfall.

Aviation

Moderate to locally breezy trade winds will persist for the next few days as high pressure remains situated northeast of the state. Brief passing showers will favor windward and mountain areas in the overnight to early morning hours. VFR conditions will prevail outside of showers.
No AIRMETs are in effect.

Marine

Little change in the forecast with the afternoon package.
High pressure will remain nearly stationary north of the islands into Monday. Meanwhile a low pressure system to the southeast of the islands will move to the west. The resultant pressure gradient over the islands will maintain the moderate to locally strong trades through Sunday. Heading into Sunday night and Monday, winds will weaken as the high to the north is eroded by a cold front moving west to east. A Small Craft Advisory (SCA) remains in effect for the windier waters near Maui County and the Big Island. This SCA is in place through Sunday afternoon, with winds expected to fall below SCA levels Sunday night. High pressure building north of the islands behind the above mentioned cold front, will allow trade winds to increase again Tuesday night into Wednesday, when another SCA may be needed.
No advisory level swell are expected this week. The current small, medium period south swell will continue to fall over the remaining daylight hours today, with a small longer period reinforcement swell expected to arrive tonight. That will hold the surf along south facing shores around waist high through Sunday. The current north swell will continue to decline through Sunday. Another small, medium period north swell is expected to arrive Thursday, causing a small bump in surf late in the week. Typical short period wind wave chop will occur along east-facing shores with the moderate to locally strong trades this weekend.

Fire weather

Humidity levels will remain dry into next week with increasing humidity and shower trends from Tuesday into Wednesday as a weak low level trough drifts from east to west across the island chain. Wind speeds will likely remain below critical fire weather thresholds for the next seven days. Temperature inversion heights near the Big Island and Maui will range from 5,500 to 6,500 feet through the weekend.

HFO Watches/Warnings/Advisories

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