West Kaua’i

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 68 to 74 near the shore to around 62 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Sunday: Breezy. Partly sunny with isolated showers. Highs 85 to 90 near the shore to around 77 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Sunday Night: Breezy. Mostly cloudy with isolated showers. Lows 69 to 74 near the shore to around 62 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 73. East winds 15 to 20 mph. Chance of rain 50 percent.

Sunday: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 88. East winds 10 to 20 mph. Chance of rain 40 percent.

Sunday Night: Breezy. Mostly cloudy with scattered showers. Lows around 73. East winds 10 to 20 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 64 to 69 in the valleys to around 59 above 4000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Sunday: Breezy. Mostly cloudy with scattered showers. Highs 74 to 84 in the valleys to around 66 above 4000 feet. East winds up to 20 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.

Sunday Night: Breezy. Mostly cloudy with scattered showers. Lows 64 to 69 in the valleys to around 59 above 4000 feet. East winds up to 25 mph. Chance of rain 50 percent.

North Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 65 to 73. East winds up to 15 mph. Chance of rain 40 percent.

Sunday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 77 to 88. East winds up to 15 mph. Chance of rain 40 percent.

Sunday Night: Mostly cloudy with scattered showers. Lows 65 to 73. East winds up to 15 mph. Chance of rain 40 percent.

East Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 64 to 76. East winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Mostly cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 73 to 85. East winds 10 to 15 mph. Chance of rain 50 percent.

Sunday Night: Mostly cloudy with scattered showers. Lows 64 to 76. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Stable and breezy trades continue through next week with passing showers focused over windward and mauka areas.

Discussion

High stability prevails as a strong inversion remains established around 6kft. The typical diurnal trend of clearing low clouds and diminishing showers was somewhat muted yesterday, and to a lesser extent today, courtesy of moisture trapped beneath this inversion in addition to the presence of high clouds which limited cloud top warming. Suspect this will be a theme with any pockets of trade wind moisture during the next few days as mid-level ridging strengthens and the inversion further strengthens and lowers through Tuesday. The lowering inversion and strengthening ridging will likewise favor strong trade winds Sunday through Tuesday. In particular, local accelerations through the windier portions of Maui County and the Big Island will be augmented by the lowering inversion and dry advection at the top of the boundary layer providing modest forcing for descent of the existing momentum field. This will enhance gustiness/downslope potential and will may warrant a Wind Advisory for those areas as early as Sunday with greater confidence for Monday and Tuesday.
The inversion then lifts and weakens slightly by Wednesday as a band of deeper trade wind moisture advances through the area bringing a slight uptick in clouds and showers for windward and mauka zones. Combined with slight weakening of governing high pressure, this will help take the edge off of strong trade winds as they weaken slightly for the remainder of the week.

Aviation

Strong high pressure to the north of the Hawaiian Islands will maintain fairly stable conditions and breezy easterly trade winds across the region through the next several days. Passing showers will favor windward and mountain areas in the overnight to early morning hours, bringing the potential for brief MVFR conditions. Otherwise, VFR conditions will prevail.
AIRMET Tango remains in effect for moderate low-level turbulence over and downwind of island terrain. This AIRMET will likely persist into early next week as breezy trade winds continue.

Marine

High pressure will remain anchored far north of the main Hawaiian Islands for the next several days, which will support fresh to strong trade winds across the area. As a result, a Small Craft Advisory remains in effect for all Hawaiian coastal waters until early Monday, but this will likely need to be extended for at least some zones as the gusty trades persist into early next week. The surface high will move eastward and weaken slightly during the second half of the week, but winds are likely to remain locally breezy in the typical windier channels and waters south of the Big Island throughout much of the next seven days.
Surf along all shores will remain mostly unchanged through the rest of the weekend, though south shore surf is expected to slowly decline as a south swell fades over the next several days. The next small, medium- to long-period south swell is expected to arrive late Tuesday through Wednesday. This swell may boost south- facing shore surf heights to near summertime averages as it peaks on Wednesday. It will then decline through the rest of next week.
Surf along east-facing shores will be rough and choppy in response to the gusty easterly trade winds.

Fire weather

Marginal fire weather conditions will exist into the middle of next week as easterly trade winds strengthen, the inversion falls from its current height of 6kft to at least 5kft and strengthens, and the resident airmass trends slightly drier. The KBDI will remain a touch below criteria (600) throughout this time limiting the liklihood of fire weather headlines.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Monday for all Hawaiian waters,

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