West Kaua’i

Tonight: Partly cloudy. Lows 72 to 77 near the shore to around 63 above 3000 feet. Southeast winds up to 10 mph shifting to the northeast after midnight.

Tuesday: Mostly sunny. Isolated showers in the morning. Highs 87 to 94 near the shore to around 80 above 3000 feet. Northeast winds up to 15 mph shifting to the southwest in the afternoon. Chance of rain 20 percent.

Tuesday Night: Mostly clear. Lows 71 to 77 near the shore to around 63 above 3000 feet. Northeast winds up to 15 mph.

South Kaua’i

Tonight: Partly cloudy with isolated showers. Lows around 75. East winds 10 to 15 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 84 to 92. Northeast winds 10 to 20 mph. Chance of rain 40 percent.

Tuesday Night: Breezy. Partly cloudy with isolated showers. Lows around 75. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Kaua’i Mountains

Tonight: Partly cloudy with isolated showers. Lows 67 to 72 in the valleys to around 62 above 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tuesday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 78 to 86 in the valleys to around 71 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tuesday Night: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Scattered showers. Lows 66 to 71 in the valleys to around 61 above 4000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.

North Kaua’i

Tonight: Partly cloudy. Isolated showers in the evening. Lows 67 to 76. East winds up to 10 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny with isolated showers. Highs 80 to 89. East winds up to 15 mph. Chance of rain 20 percent.

Tuesday Night: Partly cloudy with isolated showers. Lows 67 to 76. East winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 20 percent.

East Kaua’i

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 67 to 79. East winds up to 10 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny with isolated showers. Highs 76 to 89. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tuesday Night: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows 67 to 78. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Gentle to moderate trades will build back tonight, but warm and muggy conditions continue. A low level trough will bring an increase in clouds and showers Wednesday night into Thursday night, followed by trades building by the end of the week.

Discussion

Winds are currently light and variable with sea breezes producing low clouds across leeward sides of the islands. A few heavier showers have flared over the Big Island interior, but otherwise shower activity has been light today. With Hurricane Henriette moving away, high pressure will fill in from the east and begin to boost trade winds through the night. Expect a return to drier and more stable conditions with gentle to moderate trades over the next couple of days and clouds and light showers focused windward. Dew points will maintain around 70 degrees across the state Tuesday with a little bit of a decrease into the upper 60s by Wednesday making it still feel fairly warm even with the trades back.
By late Wednesday, latest model guidance depicts a low-level trough that propagates westward into the state. Temperature inversions across much of the state increase to near 8,000 feet during this time, increasing cloud cover and shower trends across the state, favoring windward and mountain areas of all islands. This quick-moving trough continues westward and exits on the west side of the islands by late Thursday.
Thereafter, as the weekend approaches, trades strengthen back to moderate to locally breezy and a more typical summer-like trade wind weather pattern will once again prevail.

Aviation

Light winds will continue across the island chain through tonight and then trades will gradually begin to return tomorrow. This lighter flow allowed for sea breezes to develop again this afternoon, bringing clouds and isolated showers over leeward and interior areas. Winds should remain light enough tonight, particularly along leeward areas, to see land breezes develop once again, helping to clear out inland cloud cover. As the trades return tomorrow, clouds and showers will primarily be focused over windward areas. VFR conditions will generally prevail.
No AIRMETs are currently in effect.

Marine

A weak ridge axis extending south from parent high pressure over the N Pacific is becoming established over the islands today. This signals a return to a moderate trade wind pattern through mid-week. A weak trough axis then advances westward across the state resulting in a brief period of light easterlies which may be variable at times on Thursday. Locally fresh trades then builds across area waters Friday into the weekend.
PacIOOS buoys at Barber's Point and Kaumalapau (Lanai) indicate rather steady significant wave heights through today. However, energy in the longer periods has nonetheless begun to fall off and is indicative of surf having fallen below the advisory threshold this afternoon. The High Surf Advisory has therefore been cancelled. This swell will gradually subside through the week. S shores then get a modest bump this weekend in response to a small long period pulse emanating from the S Hemisphere.
Surf along E shores remains small for the next several days as building trades remain on the lighter side. Short period chop increases this weekend as stronger trades develop. Surf along N and W shores remains tiny.

Fire weather

Critical fire weather thresholds are not expect over the next couple of days as winds will remain light to moderate with dewpoint values near or above 70 degrees for some areas. Some instability will linger around the the Big Island upper slopes through the rest of the week as inversion heights fluctuate between 5-8 kft with pockets of deep moisture moving through. Drier and more stable conditions will gradually return late this week into the weekend.

HFO Watches/Warnings/Advisories

None.

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