West Kaua’i

Tonight: Mostly clear. Lows around 68 near the shore to around 58 above 3000 feet. Light winds.

Thursday: Sunny. Isolated showers in the afternoon. Highs 82 to 88 near the shore to around 73 above 3000 feet. Light winds. Chance of rain 20 percent.

Thursday Night: Partly cloudy. Lows around 69 near the shore to around 59 above 3000 feet. Light winds becoming northeast up to 10 mph after midnight.

South Kaua’i

Tonight: Mostly clear. Lows around 69. Northeast winds 10 to 15 mph.

Thursday: Mostly sunny. Highs 81 to 88. Northeast winds 10 to 15 mph.

Thursday Night: Partly cloudy with isolated showers. Lows around 70. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Tonight: Partly cloudy with isolated showers. Lows 60 to 66 in the valleys to around 55 above 4000 feet. Light winds. Chance of rain 20 percent.

Thursday: Mostly sunny with isolated showers. Highs 74 to 80 in the valleys to around 66 above 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Thursday Night: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 60 to 67 in the valleys to around 57 above 4000 feet. East winds up to 15 mph. Chance of rain 40 percent.

North Kaua’i

Tonight: Partly cloudy with isolated showers. Lows 62 to 70. Southeast winds up to 10 mph. Chance of rain 20 percent.

Thursday: Mostly sunny with isolated showers. Highs 76 to 84. East winds up to 15 mph. Chance of rain 20 percent.

Thursday Night: Partly cloudy with isolated showers. Lows 63 to 71. East winds up to 10 mph. Chance of rain 20 percent.

East Kaua’i

Tonight: Partly cloudy with isolated showers. Lows 61 to 73. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Thursday: Mostly sunny with isolated showers. Highs 74 to 86. Northeast winds up to 10 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Thursday Night: Partly cloudy with isolated showers. Lows 62 to 74. Northeast winds up to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light to moderate trade winds will persist through Thursday, with mostly dry and stable conditions across the islands. Breezy trade winds are expected to briefly return Friday afternoon. A disturbance developing far west to northwest of the state will likely bring an increase of cloud cover over the weekend and will cause the trade winds to veer toward the southeast. Sea breezes could develop during the day Sunday with an increase of clouds and some showers across select leeward areas Sunday afternoon.

Discussion

A weak ridge of high pressure far northeast of the state continues to produce light to moderate trade winds this afternoon. Trade winds have been light enough for afternoon sea breeze across select leeward areas, which has led to some afternoon clouds and a few light sprinkles. For the most part, the lower levels of the atmosphere remains relatively dry and stable as seen on the 00Z soundings from Hilo and Lihue. The mostly dry conditions should continue through tonight.
An upper level low centered just north of Oahu will continue to drift northeast and away from the state tonight into Thursday. Thanks to the strong trade wind inversion and lower than normal precipitable water values, the upper level low has had very little impact to our weather across the state. The one area that was impacted was the summits of the Big Island, where a Wind Advisory was in effect earlier today. Wind observations did show winds dropping below advisory thresholds, thus the Wind Advisory has been cancelled. Winds will still remain a bit breezy on the summits of the Big Island through tonight.
Trade winds should strengthen a notch Friday and Saturday as surface high pressure rebuilds far northeast of the state. Passing showers should increase slightly, but shower intensity will continue to remain on the lighter side due to the stable conditions.
An area of low pressure developing far west to northwest of the state this weekend will cause the winds to veer towards the east-southeast to southeast by Sunday. This could bring an increase of hazy conditions depending on the emissions from Kilauea. Otherwise, an increase of mid to upper level clouds are expected especially on Sunday across the state. The forecast has been updated to show the increase of cloud cover this weekend, which is in line with the latest ECMWF Simulated satellite imagery. As far as precipitation this weekend, passing showers should be expected primarily over windward and mauka areas on Saturday. With the trade winds veering toward the southeast, this will cause the winds to decrease across many leeward areas of the smaller islands. This should allow for afternoon clouds and showers to develop across select leeward areas on Sunday afternoon.

Aviation

Light to moderate trade winds are expected to persist into Thursday, ushering in limited clouds and showers to windward and mauka areas. As sea breezes develop during the afternoon hours, clouds and a few showers will build over interior and leeward areas. VFR conditions are expected to prevail for most areas through tomorrow.
There are currently no AIRMETs in effect and none are anticipated through tomorrow.

Marine

A ridge to the north of the Hawaiian islands will keep trade winds gentle to moderate through Thursday night. Winds will then increase to fresh levels this weekend as high pressure to the northeast and the associated ridge strengthen. Small Craft Advisory (SCA) conditions will be possible by Friday afternoon for the typically windy areas around the Big Island and Maui.
Surf heights will remain small for most shores today. Surf heights will increase along north and west facing shores tonight through Thursday as a brief north-northwest (330-340 deg) swell moves through the region. A larger north-northwest (330-340 deg) swell will arrive by early Saturday morning, producing moderate surf heights along north and west facing shores, before rapidly declining Saturday night through Sunday.
For south facing shores, surf heights will gradually increase today and tonight and stay slightly elevated through Saturday as a series of southerly pulses move through. Surf will then decrease Sunday through next week as swell fades.

HFO Watches/Warnings/Advisories

None.

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