West Kaua’i

Tonight: Mostly clear. Isolated showers after midnight. Lows 69 to 74 near the shore to around 61 above 3000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs 84 to 90 near the shore to around 76 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Wednesday Night: Mostly clear. Isolated showers after midnight. Lows 69 to 74 near the shore to around 61 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows around 72. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 80 to 88. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday Night: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows around 72. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Mostly cloudy with scattered showers. Lows 64 to 70 in the valleys to around 59 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 74 to 84 in the valleys to around 67 above 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Wednesday Night: Mostly cloudy with scattered showers. Lows 64 to 69 in the valleys to around 58 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

North Kaua’i

Tonight: Partly cloudy with scattered showers. Lows 65 to 73. East winds up to 10 mph. Chance of rain 40 percent.

Wednesday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 77 to 86. East winds up to 15 mph. Chance of rain 50 percent.

Wednesday Night: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 74. East winds 10 to 15 mph. Chance of rain 30 percent.

East Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 64 to 76. East winds around 10 mph. Chance of rain 50 percent.

Wednesday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 73 to 86. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday Night: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 63 to 76. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Light trades prevail across the Hawaiian islands as a surface trough persists just to the north. As this trough exits the vicinity of the islands by mid-week, high pressure will build to the north in its wake, backing trades to a more easterly component and increasing to a more moderate to breezy range through the remainder of the week. Expect drier conditions during this time as well. By the weekend and into next week, trades could become moderate to strong as high pressure is forecast to build further.

Discussion

Light trades prevail across the state in response to a surface trough that has persisted north of the islands that has deteriorated the pressure gradient. Some localized sea breezes may occur throughout the day again today, triggering possible leeward and interior area showers, but will be far less energized in comparison to earlier this week as the surface trough weakens and exits the vicinity to the west. Thereafter, the surface high well north of the island chain will rebuild, allowing trades to gradually back out of the east and strengthen slightly to moderate to localized breezy conditions.
As the week progresses, expect drier conditions to ensue as drier air is progged to move into the vicinity of the islands. Despite this, typical trade showers can be expected across windward and mauka areas, but at modest levels given the lack of available moisture. This trend will continue through the weekend and into next week.
Meanwhile, latest model guidance of the GFS and Euro remains in pretty good agreement that trades will strengthen further, becoming breezy to localized strong at times into early next week. The conjunction of drier conditions with these stronger trades could elevate fire weather concerns. While this is still several days out, and confidence remains low at the moment, conditions will be monitored by future shifts leading up to the weekend and into next week.

Aviation

Light trades will prevail, however, as a diffused surface trough exits the region to the west, the trades will strengthen slightly and gradually back out of the east. Some leeward and interior sea breeze clouds and showers will be possible again, but will likely be less active than yesterday. Brief periods of MVFR conditions will be possible in any showers, but overall VFR conditions should prevail.
No AIRmets are in effect at this time.

Marine

A weak high pressure ridge anchored north of the Hawaiian Islands will keep gentle to fresh easterly trade winds in the forecast through Friday. The ridge will build in north of the island chain by Saturday, increasing trade winds into the fresh to locally strong range into early next week. There are no Small Craft Advisories (SCA) currently in effect, however stronger winds forecast to arrive this weekend will likely bring a return to SCA conditions for wind over the typically windier waters around Maui and the Big Island.
A small long period south swell will hold around 2 feet through Wednesday. Another smaller longer period south swell then builds into the regional waters from Thursday onward, keeping surf heights along south facing shores fairly steady. Surf heights along E shores matches trade wind trends, subsiding and remaining small this week then increasing slightly this weekend. Surf heights along west facing shores will see some south swell wrap, with north facing shores remaining nearly flat.

HFO Watches/Warnings/Advisories

None.

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