West Kaua’i

Tonight: Mostly clear. Lows around 70 near the shore to around 60 above 3000 feet. Northeast winds up to 15 mph.

Sunday: Sunny and breezy. Highs 83 to 89 near the shore to around 75 above 3000 feet. East winds up to 20 mph.

Sunday Night: Mostly clear. Lows 68 to 73 near the shore to around 61 above 3000 feet. East winds up to 15 mph.

South Kaua’i

Tonight: Mostly clear with isolated showers. Lows around 71. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Breezy. Sunny with isolated showers. Highs 81 to 88. East winds 10 to 20 mph. Chance of rain 20 percent.

Sunday Night: Partly cloudy with isolated showers. Lows around 71. East winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Tonight: Partly cloudy with isolated showers. Lows 61 to 69 in the valleys to around 59 above 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs 76 to 82 in the valleys to around 66 above 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Sunday Night: Breezy. Mostly cloudy with numerous showers. Lows 62 to 70 in the valleys to around 59 above 4000 feet. East winds up to 20 mph. Chance of rain 60 percent.

North Kaua’i

Tonight: Mostly clear with isolated showers. Lows 64 to 71. Southeast winds up to 15 mph. Chance of rain 20 percent.

Sunday: Sunny with isolated showers. Highs 77 to 86. Southeast winds up to 15 mph. Chance of rain 20 percent.

Sunday Night: Partly cloudy with scattered showers. Lows 64 to 72. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Tonight: Mostly clear with isolated showers. Lows 64 to 75. East winds up to 15 mph. Chance of rain 20 percent.

Sunday: Sunny with isolated showers. Highs 74 to 85. East winds 10 to 15 mph. Chance of rain 20 percent.

Sunday Night: Mostly cloudy with scattered showers. Lows 64 to 75. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Locally breezy trades will deliver clouds and showers to windward and mauka areas through next week.

Discussion

Water vapor imagery indicates ample mid-level dry air established over the islands in association with a corridor of active subsidence. This is evident on this afternoon's soundings out of Hilo and Lihue which are extremely stable and imply a gently sloped inversion from around 6kft at Lihue to 5kft at Hilo. At the surface, this translates to a relatively dry and stable trade wind pattern. Upstream visible imagery suggests little moisture embedded in upstream trades which increases confidence in maintaining a forecast on the drier side of climatology. Benign, locally breezy trade wind weather prevails through the next week as mid-level ridging persists. Slight increase in available moisture occurs coincident with an approaching weak frontal zone during mid-week offering potential for increased coverage of trade wind showers, mainly windward and mauka.

Aviation

Moderate to locally breezy east southeast flow will limit most shower activity to windward and mauka locations this evening into tonight with brief periods of MVFR conditions from low cigs and visibly. Otherwise, VFR should prevail.
This breezy east southeast flow pattern may generate low level wind shear/turbulence at Kahului airport through late afternoon.
AIRMET Tango is in effect for mod turb below 070 for all islands and will likely be needed for a few days.

Marine

High pressure northeast of the islands and a surface ridge will drive fresh to strong easterly trade winds through the rest of the weekend. A slight decrease is possible over the western end of the state late Sunday into Monday as a front passes far north of the area. A stronger high and ridge will then develop Monday night through midweek, strengthening trade winds back into the fresh to strong range. Advisory-level winds should continue over the windier marine zones around Maui County and the Big Island, with an expansion of stronger trades to additional waters from Tuesday through midweek.
Surf along south-facing shores will lower gradually tonight into Sunday as the current south swell declines. A fresh, long- period south-southwest swell (1 foot, 19 seconds) is expected to arrive by Sunday night, peaking Monday into Tuesday, with surf returning to around average. A gradual downward trend is expected from late Tuesday through midweek.
Surf along east-facing shores will hold steady near seasonal averages through next week due to the persistent trades.
Surf along north-facing shores will gradually ease over the weekend as a medium-period north-northwest swell fades. A series of small northwest swells next week will keep surf from going flat. Friday could see a small to medium north swell.

HFO Watches/Warnings/Advisories

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

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