West Kaua’i

Tonight: Mostly clear. Lows around 74 near the shore to around 62 above 3000 feet. Northeast winds up to 10 mph.

Thursday: Mostly sunny. Isolated showers in the afternoon. Highs 86 to 92 near the shore to around 78 above 3000 feet. Light winds. Chance of rain 20 percent.

Thursday Night: Mostly clear. Lows 71 to 76 near the shore to around 62 above 3000 feet. Light winds becoming northeast up to 10 mph after midnight.

South Kaua’i

Tonight: Partly cloudy with isolated showers. Lows around 74. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Thursday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 84 to 91. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Thursday Night: Partly cloudy with scattered showers. Lows around 74. Northeast winds around 10 mph. Chance of rain 30 percent.

Kaua’i Mountains

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 71 in the valleys to around 60 above 4000 feet. Northeast winds up to 15 mph. Chance of rain 40 percent.

Thursday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs 76 to 85 in the valleys to around 69 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Thursday Night: Partly cloudy with scattered showers. Lows 65 to 70 in the valleys to around 60 above 4000 feet. East winds around 10 mph. Chance of rain 40 percent.

North Kaua’i

Tonight: Partly cloudy with scattered showers. Lows 66 to 75. Northeast winds 10 to 15 mph shifting to the east after midnight. Chance of rain 40 percent.

Thursday: Partly sunny with scattered showers. Highs 78 to 89. Northeast winds up to 10 mph. Chance of rain 40 percent.

Thursday Night: Partly cloudy with scattered showers. 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. Scattered showers. Lows 66 to 77. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Thursday: Partly sunny with scattered showers. Highs 76 to 88. Northeast winds around 10 mph. Chance of rain 50 percent.

Thursday Night: Mostly cloudy with scattered showers. Lows 65 to 77. Northeast winds around 10 mph. Chance of rain 40 percent.

Detailed Forecast

Synopsis

A high pressure ridge north of the Hawaiian Islands will bring moderate to locally breezy trades today. A low level trough will move through the region on Thursday, weakening the trades and increasing clouds and showers through Friday. High pressure will build back in across the region Saturday bringing a brief return of moderate trades. Another brief increase in clouds, showers and humidity levels will develop from Sunday into Monday as the remnants of Ivo move through the state. A more stable and dry weather pattern looks to return from Tuesday onward.

Discussion

Looking at the latest satellite and radar imagery we see a few bands of low level clouds riding in on the trades with some some isolated showers embedded in these clouds. Winds continue to be in the moderate to locally breezy range but changes are coming.
Tomorrow the weather pattern changes a bit as an easterly wave drifting in on the trades moves from east to west up the island chain. Trade winds will decrease and island heating will drive afternoon sea breezes across leeward areas of each island. An increase in clouds and showers is likely through Friday morning. Friday afternoon into early Sunday the upper level trough lifts northward and a stable upper ridge moves directly over the islands, decreasing clouds and showers.
By Sunday afternoon, remnants of what was tropical cyclone Ivo will move from east to west through the chain. This trough will have slightly different island by island impacts as deeper moisture and dynamics are associated with it. Humidity levels, moderate trades, increasing cloudiness and scattered showers can be expected through Monday.
A high pressure ridge will build back into the region on Tuesday, bringing a more typical dry stable summer weather pattern across the state through at least mid-week.

Aviation

Dry with widely scattered -SHRA under moderate trade winds through Thursday. While VFR conditions will prevail there are some pockets of MVFR. The islands are under mid to upper level ridging and will result in continued stable conditions. Mountain waves depicted by today's visible satellite imagery proof of this stability.
AIRMET Tango is in effect to cover turbulence immediately south through west of all island mountains.

Marine

The ridge north of the state is beginning to weaken ahead of a surface trough approaching from the east. As a result, trade winds are on the decline and the Small Craft Advisory (SCA) for the windier waters and channels around Maui County and the Big Island has been cancelled. As the trough moves westward through the island chain through Thursday, winds will diminish to light easterlies which may become variable in direction at times. Moderate to locally fresh trades return Friday becoming locally strong over the weekend.
The current south swell will continue to gradually decline today. Background small, long-period south southwest swell should fill in Thursday keeping surf slightly below average. A couple of small, long-period southerly swells is expected to fill by the weekend, keeping surf heights near average into early next week, though likely remaining below advisory level.
Surf along east facing shores will see a slight uptick later today through Friday due to a small, medium-period northeast swell. Short-period chop increases this weekend again as stronger trades develop. Surf along north facing shores will remain tiny through the forecast period.

Fire weather

Weather conditions will likely remain below critical fire weather thresholds into early next week. A low level disturbance will move into the region from Thursday to Friday morning producing a slight increase in clouds and showers. Another low level disturbance associated with the remnants of former tropical cyclone Ivo will increase humidity levels and shower trends on Sunday and Monday. A return to lower humidity levels will develop by Tuesday as a stable upper level ridge builds back over the island chain.

HFO Watches/Warnings/Advisories

None.

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