West Kaua’i

Tonight: Mostly clear. A 20 percent chance of showers after midnight. Lows around 74 near the shore to around 62 above 3000 feet. East winds around 10 mph.

Saturday: Sunny. Highs 88 to 94 near the shore to around 81 above 3000 feet. East winds around 10 mph.

Saturday Night: Mostly clear. A 20 percent chance of showers after midnight. Lows 71 to 76 near the shore to around 62 above 3000 feet. East winds around 10 mph.

South Kaua’i

Tonight: Partly cloudy in the evening then becoming mostly cloudy. A 50 percent chance of showers. Lows around 74. Northeast winds 10 to 15 mph.

Saturday: Mostly sunny. Chance of showers in the morning, then slight chance of showers in the afternoon. Highs 84 to 93. East winds 10 to 15 mph. Chance of rain 40 percent.

Saturday Night: Partly cloudy with a 30 percent chance of showers. Lows around 74. East winds 10 to 15 mph.

Kaua’i Mountains

Tonight: Partly cloudy with a 50 percent chance of showers. Lows 66 to 71 in the valleys to around 61 above 4000 feet. East winds 10 to 15 mph.

Saturday: Mostly sunny. Chance of showers in the morning, then slight chance of showers in the afternoon. Highs 78 to 87 in the valleys to around 70 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Saturday Night: Partly cloudy with a 50 percent chance of showers. Lows 65 to 71 in the valleys to around 60 above 4000 feet. East winds 10 to 15 mph.

North Kaua’i

Tonight: Partly cloudy with a 40 percent chance of showers. Lows 66 to 75. East winds 10 to 15 mph.

Saturday: Mostly sunny. A 20 percent chance of showers in the morning. Highs 80 to 90. East winds around 10 mph.

Saturday Night: Partly cloudy. Chance of showers in the evening, then slight chance of showers after midnight. Lows 66 to 75. East winds around 10 mph. Chance of rain 30 percent.

East Kaua’i

Tonight: Partly cloudy in the evening then becoming mostly cloudy. A 50 percent chance of showers. Lows 66 to 78. East winds around 10 mph.

Saturday: Mostly sunny. Chance of showers in the morning, then slight chance of showers in the afternoon. Highs 77 to 89. East winds 10 to 15 mph. Chance of rain 50 percent.

Saturday Night: Mostly cloudy with a 40 percent chance of showers. Lows 66 to 78. East winds around 10 mph.

Detailed Forecast

Synopsis

High pressure north of the islands will maintain moderate to locally breezy trade winds through the weekend, followed by a slight decrease in winds early next week. Mostly dry weather will continue to persist with a few light showers possible across windward and mauka areas.

Discussion

This afternoon's satellite imagery shows mostly dry conditions across the state with only a handful of rainfall stations showing measurable precipitation during the past 6 hours. Afternoon soundings from Hilo and Lihue show a typical dry summertime sounding with precipitable water values around 1.2 inches and a strong inversion starting at around 5500 feet.
For Saturday, we will continue to see dry summertime conditions with moderate to locally breezy trade winds. Starting Sunday, a trough developing north of the state will cause the ridge of high pressure to weaken and will likely cause the winds to decrease and veer toward the east-southeast through Monday. Besides the winds veering towards the east-southeast and decreasing a touch on Sunday, the overall theme will continue with mostly dry conditions expected on Sunday. Although with the winds weakening some, we could see more areas with sea breezes during the day Sunday and Monday, which could bring some afternoon cloud cover for select leeward areas.
By Tuesday, we should see the trough lift northward and away from the state and a new high will be building far north of the state. This should bring the return of our typical breezy trade winds. As our breezy trade winds return, we could see a slight increase of some windward showers, but overall no significant precipitation is expected through the middle of next week.

Aviation

Moderate to breezy easterly trade winds will persist through the forecast period. Clouds and showers will remain focused primarily over the windward and mountain areas, particularly overnight and into the early morning hours. Brief MVFR conditions will be possible in showers, otherwise VFR will likely prevail.
No AIRMETs are currently in effect.

Marine

High pressure north of the Hawaiian Islands maintains fresh to strong trades through early next week. The Small Craft Advisory (SCA) remains in effect and will likely continue for the windier waters of Maui County and the Big Island into next week.
A series of small overlapping medium and long period S (170-190 degree) swells continues through Saturday maintaining surf near the summertime average along S shores. Surf then diminishes to background levels early next week as swell energy fades. Another small, long period S swell arrives by Tuesday.
Short period chop continues for E facing shores through the forecast period due to persistent fresh trades. Surf along N facing shores remains nearly flat.

Fire weather

Elevated fire weather conditions will continue through Saturday due to the low humidity values. While we did see select areas with humidities down to the mid 30's to low 40's this afternoon, wind speeds stayed at moderate speeds thus below Red Flag conditions. Humidities are expected to increase a touch on Saturday, but overall dry conditions will continue to persist. Once again wind speeds will be the limiting factor on Saturday with winds just below Red Flag thresholds expected. A ridge aloft will maintain an inversion between 5,000 and 6,500 ft through the weekend. Wind speeds are expected to decrease some Sunday into early next week but increase back to our typical moderate to locally breezy speeds Tuesday into Wednesday of next week, which could bring elevated fire weather conditions once again.

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.

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