Photo Credit: Brendan Stephen

West Kaua’i

Today: Mostly sunny. Isolated showers in the afternoon. Highs around 87 near the shore to around 75 above 3000 feet. Light winds becoming southwest up to 10 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers early in the evening. Lows around 70 near the shore to around 58 above 3000 feet. Northeast winds around 10 mph in the evening becoming light. Chance of rain 20 percent.

Friday: Sunny in the morning, then partly sunny with a 40 percent chance of showers in the afternoon. Highs 85 to 90 near the shore to around 76 above 3000 feet. Light winds.

South Kaua’i

Today: Mostly sunny with isolated showers. Highs 83 to 88. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 66 to 71. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny with a 20 percent chance of showers. Highs 83 to 89. Northeast winds around 10 mph.

Kaua’i Mountains

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 75 to 82 in the valleys to around 65 above 4000 feet. Light winds becoming northeast up to 15 mph in the afternoon. Chance of rain 40 percent.

Tonight: Mostly cloudy early in the evening then becoming partly cloudy. Scattered showers early in the evening, then slight chance of showers in the late evening and overnight. Lows 59 to 65 in the valleys to around 55 above 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Friday: Mostly sunny with slight chance of showers in the morning, then mostly cloudy with chance of showers in the afternoon. Highs 75 to 82 in the valleys to around 66 above 4000 feet. Northeast winds around 10 mph. Chance of rain 40 percent.

North Kaua’i

Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 78 to 86. East winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 30 percent.

Tonight: Partly cloudy with a 20 percent chance of showers. Lows 62 to 71. East winds 10 to 15 mph.

Friday: Mostly sunny with slight chance of showers in the morning, then partly sunny with chance of showers in the afternoon. Highs 78 to 86. Northeast winds around 10 mph. Chance of rain 40 percent.

East Kaua’i

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 77 to 85. Northeast winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 40 percent.

Tonight: Partly cloudy with a 20 percent chance of showers. Lows 60 to 73. Northeast winds 10 to 15 mph.

Friday: Mostly sunny with slight chance of showers in the morning, then partly sunny with chance of showers in the afternoon. Highs 77 to 86. Northeast winds around 10 mph. Chance of rain 40 percent.

Detailed Forecast

Synopsis

Weak trade winds will veer to the southeast as a front stalls just to our north this weekend. An area of enhanced tropical moisture will push across the island chain from the southeast, increasing clouds and showers across much of the state from Saturday into early next week. Shower coverage could be more widespread each afternoon and evening before diminishing each night.

Discussion

Moisture within light to moderate trade flow fuels clouds and showers across windward portions of the islands this morning. Earlier convective activity across windward portions of the Big Island has diminished significantly. Models show that a front approaching from the north will move closer to Kauai and weaken the trades today. Relatively dry conditions are expected across Kauai ahead of the front while greater moisture remains farther to the east. By tonight into Friday morning, more moisture will be drawn northward towards the state as winds continue to weaken and veer to southeasterlies. This will result in a hybrid sea-breeze pattern that could increase clouds and showers across leeward and interior sections of the islands by late Friday morning.
Winds will remain light into the weekend as they veer out of the southeast, allowing the Big Island to block much of the rest of the state. Afternoon sea breezes and overnight land breezes will continue through the weekend and into next week. With abundant tropical moisture in place, expect a generally wet pattern with showers favoring interior and leeward areas during the afternoons and evenings before diminishing each night. Confidence remains low concerning the amount and effects of the incoming tropical moisture this weekend. Our forecast reflects the possibility of higher rainfall probabilities and more widespread rainfall this weekend and beyond, especially in the afternoons and evenings.

Aviation

A band of moisture over the central islands will produce passing showers this morning. Expect a hybrid wind pattern with light to moderate trade winds over eastern slopes, transitioning to a sea breeze pattern each afternoon over leeward areas. Mountain and interior showers are possible each afternoon switching to windward areas in the overnight time periods.
AIRMET Sierra in effect for mountain obscuration over north through east sections of Oahu, Molokai and Maui. The Big Island also has the same AIRMET in effect from Laupahoehoe to Hilo to Volcano. This AIRMET will diminish around sunrise.

Marine

Gentle to moderate trade winds will prevail over most areas through tomorrow. Winds will ease Saturday through Monday, possibly becoming light and variable, as a deep low passes about 750 nm north of the state and pushes a weak surface ridge near the state. The low will lift to the north Monday and Tuesday, allowing the ridge to strengthen, and east to southeast winds will likely rebuild.
Surf along north facing shores will be small today but will build tonight as the next north swell fills in. This next swell will produce surf around the High Surf Advisory level tomorrow into Monday before dropping early next week. Since trade winds will be suppressed across the region through much of the week, the main source for east shore surf will be wrapping north swell. Surf along south facing shores will remain small today and tomorrow as the current south- southwest swell slowly fades today and another small, long period south swell fills in later today and tomorrow. A slightly larger south swell will likely produce surf above the October average during the weekend.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov