Photo Credit: Brendan Stephen

West Kaua’i

Today: Sunny with isolated showers. Highs 79 to 86 near the shore to around 72 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 64 to 70 near the shore to around 58 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Sunday: Sunny. Isolated showers in the morning. Highs 78 to 86 near the shore to around 71 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Breezy. Mostly sunny with scattered showers. Highs 77 to 85. Northeast winds 10 to 20 mph. Chance of rain 30 percent.

Tonight: Partly cloudy with scattered showers. Lows around 68. Northeast winds 10 to 15 mph. Chance of rain 30 percent.

Sunday: Mostly sunny. Breezy. Scattered showers in the morning. Highs 77 to 85. Northeast winds 10 to 20 mph. Chance of rain 30 percent.

Kaua’i Mountains

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 71 to 79 in the valleys to around 62 above 4000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 59 to 67 in the valleys to around 56 above 4000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Sunday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 70 to 78 in the valleys to around 62 above 4000 feet. East winds up to 15 mph. Chance of rain 40 percent.

North Kaua’i

Today: Mostly sunny with scattered showers. Highs 73 to 82. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with scattered showers. Lows 61 to 69. Southeast winds 10 to 15 mph. Chance of rain 30 percent.

Sunday: Mostly sunny. Scattered showers in the morning. Highs 73 to 81. East winds up to 15 mph. Chance of rain 30 percent.

East Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 70 to 82. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 61 to 72. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Sunday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 69 to 82. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Detailed Forecast

Synopsis

Moderate to locally breezy trades will prevail through the weekend before weakening early next week as a decaying cold front approaches the area. Showers will mainly focus over windward and mauka areas during this time.

Discussion

Latest satellite and radar analysis shows a cutoff low developing south of the Big Island from an elongated trough. This feature is helping to provide some instability upstream of the state. Radar shows a few moderate showers moving westward embedded with the breezy trades generated by a strong surface high to the far northeast. As we head into the morning and afternoon hours expect a slight decrease in shower coverage, but the possibility for brief heavy showers will still be greater around Maui County and the Big Island. The kona slopes of the Big Island will see an increase in cloud and showers as the sea breeze kicks in during the afternoon hours with an isolated chance of thunderstorms as instability lingers from the nearby upper level low.
Breezy trades will hold through Sunday before gradually weakening during the first half of next week due to a weak front approaching and passing north of the state and the strong high northeast of the state weakens. Clouds and showers will remain focused along windward and mauka regions. The eastern half of the state will still have a good chance for enhanced tradewind showers as the upper level low weakens and shifts north just east of the Big Island Sunday night into Monday. Mid- level ridging will build over the state as the upper low exits east of the state, creating a gentle dry and stable tradewind weather pattern through Tuesday. A strong cold front approaching the state midweek will shift the winds out of the southeast and continue to weaken allowing for land/seabreezes to develop. The front is expected to quickly sweep across the state during the second half the next week.

Aviation

Moderate to locally breezy trades will bring scattered showers to mainly windward locations this morning. However, an isolated shower or two could pass over the terrain and onto leeward sides. Weak instability from an upper level low south of the Big Island will bring heavier showers, along with isolated thunderstorms, to leeward sections of the Big Island this afternoon.
AIRMET Tango remains in effect for low level turbulence associated with the breezy trade winds.

Marine

Surface high pressure far northeast will drive moderate to locally strong trades through the weekend. The trades appear to ease up slightly early next week as the ridge to the north weakens. The trades are expected to become disrupted entirely Wednesday and Thursday, with light winds over the marine area. A Small Craft Advisory (SCA) is now in effect for the typically windy waters around Maui and the Big island through 6 pm Sunday.
The current northwest swell will decline today. Meanwhile, a new long-period northwest swell will arrive late this afternoon, peak Sunday into Sunday night, then lower on Monday. This swell will give a slight boost to surf along north and west facing shores, but will likely remain below advisory levels. The next in the train of northwest swells will arrive late Sunday night, peak Monday through Tuesday, then gradually decline through Thursday. This swell may bring another round of advisory level surf to most north and west facing shores Monday afternoon through Tuesday night. A much larger long-period northwest swell could bring warning level surf to most north and west facing shores next Friday.
East shore surf not exposed to the series of northwest swells will gradually rise today as the trades return over and upstream of the islands. Surf along east facing shores will then hold relatively steady Sunday, then lower a bit Monday and Tuesday as the trades ease. East shore surf looks to become very small Wednesday and Thursday as the trades become disrupted, with a north swell potentially giving surf a boost next Friday.
South shore surf will remain very small through the middle of next week. An out of season long-period south swell may move through the islands late next week, bringing a sizable boost to south shore surf.

Fire weather

No critical fire weather conditions expected through the forecast period as winds speeds are expected to remain below 17 kt.

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.

Kauai Now Weather is brought to you by Blue Hawaiian Helicopters.