West Kaua’i

Tonight: Partly cloudy with isolated showers. Lows around 69 near the shore to around 60 above 3000 feet. Light winds. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 82 to 88 near the shore to around 75 above 3000 feet. Light winds. Chance of rain 40 percent.

Friday Night: Partly cloudy. Isolated showers after midnight. Lows around 69 near the shore to around 60 above 3000 feet. Light winds. Chance of rain 20 percent.

South Kaua’i

Tonight: Partly cloudy with scattered showers. Lows 68 to 74. Northeast winds around 10 mph. Chance of rain 40 percent.

Friday: Mostly sunny with isolated showers. Highs 77 to 87. East winds 10 to 15 mph. Chance of rain 20 percent.

Friday Night: Partly cloudy with isolated showers. Lows 68 to 74. Northeast winds around 10 mph. Chance of rain 20 percent.

Kaua’i Mountains

Tonight: Mostly cloudy with scattered showers. Lows around 65 in the valleys to around 57 above 4000 feet. Light winds. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs 73 to 80 in the valleys to around 66 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy with scattered showers. Lows around 65 in the valleys to around 57 above 4000 feet. Light winds. Chance of rain 40 percent.

North Kaua’i

Tonight: Partly cloudy with scattered showers. Lows 62 to 72. East winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Friday: Mostly sunny with isolated showers. Highs 70 to 84. East winds up to 10 mph. Chance of rain 20 percent.

Friday Night: Partly cloudy with isolated showers. Lows 62 to 72. Light winds. Chance of rain 20 percent.

East Kaua’i

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 64 to 74. Northeast winds around 10 mph in the evening becoming light. Chance of rain 50 percent.

Friday: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 76 to 84. Northeast winds up to 10 mph. Chance of rain 40 percent.

Friday Night: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows 64 to 74. Light winds. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light to moderate trades will gradually weaken through Saturday, allowing for the development of localized sea breezes which will bring clouds and a few showers to leeward and interior areas each afternoon, followed by clearing with land breezes overnight. Moderate to locally breezy trades will return early next week, bringing back the typical windward and mauka showers. A slight weakening of the trade wind flow may unfold for the latter part of next week.

Discussion

Light to moderate trades will gradually weaken through Saturday as the subtropical high to the northeast gets pushed farther away, displaced by a low pressure system developing to the far north and advancing toward the Gulf of Alaska. These lighter background winds across the state will allow for localized sea and land breeze cycles to develop, bringing afternoon leeward and interior showers, followed by clearing overnight. The sea breeze cycle already kicked off earlier this afternoon, with showers developing most notably over leeward Oahu and the Kona slopes of the Big Island. With drier air filtering over the state this afternoon and lingering through the weekend, expect shower activity to be somewhat limited during this period.
Moderate to locally breezy trades gradually return Sunday night into early next week as ridging builds back in from the northeast. Pockets of deeper moisture caught up in the redeveloping trade wind flow will bring periodic upticks in windward and mauka showers, particularly Sunday night into Monday.
Another developing low to the north may cause winds to weaken slightly across the islands for the latter half of the work week. An area of enhanced moisture will move in from the east around the same time, boosting dew points and bringing an uptick in shower activity, particularly across the eastern end of the state. Most of these showers will likely be focused over windward and mauka areas, but if the winds become light enough, there may also be some isolated sea breeze showers over leeward and interior areas.

Aviation

Trade winds will become gradually weaker through Saturday as the surface pressure gradient over the islands weakens. Low ceilings and showers are expected, mainly over windward and mauka areas today and tonight. However, more showers will develop in leeward areas starting tomorrow and lasting through the weekend. MVFR conditions are possible in isolated heavier showers, otherwise VFR.
AIRMET Sierra is in effect for mountain obscuration for windward locations of Oahu, Maui, and Big Island. Condition will likely extend through tonight.

Marine

Expect light to moderate easterly winds to develop tonight and hold through Saturday as a weak front passes far north of the state. Moderate to fresh easterly trades will return Sunday through early next week as a surface ridge strengthens north of the area.
A mix of small pulses of south-southwest swells is still anticipated for tonight through Friday, recharging near average surf along south facing shores.
Long-period energy from a storm that passed within our swell window around New Zealand earlier this week is peaking at the Samoa Buoy this afternoon at around 15 feet 20 seconds. Surf heights are expected to gradually build locally Saturday and peak Sunday into Monday before slowly declining through the first half of next week. This swell will also coincide with the peak monthly tides and will lead to significant wave runup and minor coastal flooding during the first half of next week, particularly during the peak daily high tide cycles. A marine weather statement is also anticipated due to the threat of harbor surges. South shore surf will remain elevated through much of next week due to the slow decline of this large south swell and a series of more overlapping southerly swells.
East shore surf will slowly decline below seasonal averages through the the weekend as trades ease, then pick up a notch next week as more breezy trades return. No significant swells expected elsewhere.

HFO Watches/Warnings/Advisories

None.

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

Check out their Kaua‘i Helicopter Tours today!

Data Courtesy of NOAA.gov