West Kaua’i

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 69 near the shore to around 59 above 3000 feet. Northeast winds around 10 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 83 to 89 near the shore to around 75 above 3000 feet. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Friday Night: Partly cloudy. Isolated showers after midnight. Lows 68 to 73 near the shore to around 61 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 70. Northeast winds 10 to 15 mph. Chance of rain 30 percent.

Friday: Mostly sunny with scattered showers. Highs 81 to 88. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Friday Night: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 71. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Partly cloudy with scattered showers. Lows 61 to 67 in the valleys to around 57 above 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 73 to 81 in the valleys to around 65 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Friday Night: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Scattered showers. Lows 62 to 69 in the valleys to around 58 above 4000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

North Kaua’i

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 63 to 71. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 76 to 85. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday Night: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 64 to 72. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 62 to 74. Northeast winds around 10 mph. Chance of rain 50 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 73 to 85. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Friday Night: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 64 to 75. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Trades increase Friday and then veer east-southeasterly for the weekend. Stable conditions will keep windward and mauka showers more isolated and brief. Breezy trades are expected next week with windward and mauka showers.

Discussion

Current radar and satellite trends show a few isolated showers riding on the trades with most places seeing partly cloudy skies. With trades on the light to moderate side some sea breezes can be expected on western terrains sheltered areas.
An upper-level low just to the north of the islands will slowly drift northeastward over the next few days. In the meantime another low will be forming to the west. With a trough in place in the low to mid levels, as well as a strengthening surface high to our north, combined with both aforementioned lows, expect an increase in the trades for Friday. As the trough shifts further south for the weekend trades will veer southeasterly. This could bring some hazy conditions to at least the eastern side of the state due to VOG-volcanic smog.
For next week, guidance is showing some breezy easterly trade winds to blow across the state. Some brief passing showers will remain in the forecast from Tuesday onward, favoring the windward and mauka slopes.

Aviation

AIRMET SIERRA has been issued for SW Big Island due to mountain obscuration from clouds and showers as onshore seabreezes have kicked in this afternoon. This is expected to last until shortly after sunset as land breezes take over and push any remaining clouds and showers offshore. Elsewhere, moderate trade wind pattern gradually strengthen overnight into Friday. An area of enhanced clouds and showers may pass over or near Kauai and Oahu tonight with possible MVFR conditions and embedded showers. Overall VFR conditions will prevail with limited shower potential.

Marine

Building high pressure north of the islands will strengthen the trade wind flow, with fresh to strong trades expected Friday. Winds are forecast to reach Small Craft Advisory (SCA) levels by Friday afternoon in the typical windier waters near Maui County and the Big Island. The high is expected to move to the far northeast of the islands over the weekend, which could cause winds to turn a bit more southeasterly, but SCA level winds are expected to remain in the typical windier waters through the weekend. The global models show a front passing far north of the islands this weekend, with the high building back in north of the islands early next week. This could bring another uptick to the winds, which may require the SCA to be expanded to additional coastal waters.
The current long-period sout-southwest swell should hold through Friday at near average levels, and then gradually decline this weekend into early next week. Through much of next week, expect a mix of long- period background south- southwest and shorter- period southeast swell.
Overlapping north-northwest swells will maintain surf along north and west facing shores at average levels into Friday. A second swell will drive heights above average on Saturday. Surf will gradually lower to seasonal levels Sunday through early next week.
Surf along east-facing shores will gradually build over the weekend and into early next week as trade winds return.

HFO Watches/Warnings/Advisories

None.

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