Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Breezy. Mostly sunny with isolated showers. Highs around 86 near the shore to around 73 above 3000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 69 near the shore to around 57 above 3000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 86 near the shore to around 73 above 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

South Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs around 83. Northeast winds 20 to 25 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers. Lows 66 to 72. Northeast winds around 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs around 83. East winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Partly sunny with scattered showers. Highs around 77 in the valleys to around 66 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 61 in the valleys to around 53 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 around 77 in the valleys to around 66 above 4000 feet. East winds 10 to 15 mph. Chance of rain 60 percent.

North Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 75 to 84. East winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 71. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 75 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 76 to 83. Northeast winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers. Lows 59 to 74. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 76 to 83. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Moderate to locally strong trade winds will focus clouds and showers over the windward and mauka areas today, with showers being more prevalent over the Big Island. The trades are expected to weaken some tonight, and then rebound again starting later Tuesday. A passing trough will bring an increase in shower activity Tuesday and Wednesday.

Discussion

Made some changes to the Big Island PoPs and associated fields for today and tonight, to boost PoPs following the trend in the high resolution models. Have also made some tweaks to the winds across the area through tomorrow. In the longer term have trended the PoPs and associated fields towards a blend of the models.
High pressure far to the north will maintain a trade wind flow through the week. The locally strong trades today are expected to weaken a bit tonight and tomorrow morning, as a surface trough approaches from the northeast. This trough is also expected to boost some shower activity.
The overnight sounding from Hilo once again was saturated due to the showers on the windward side of the Big Island, and once again no inversion of note. The high resolution models show PoPs remaining elevated for the Big Island, with the HREF indicating some heavier showers will remain possible. All the pieces aren't lining up in one place, so as mentioned above, have boosted PoPs upwards on the Big Island.
Heading into the weekend, the high will be edging to the east, and winds are expected to turn to a more southeasterly direction. The global models show an upper level trough forming to the northwest of the islands, and a surface front far to the northwest approaching. These features could increase rain activity late into the weekend into next week.

Aviation

Conditions are slowly improving over Windward Big Island where the heaviest showers are now focused offshore along the land breeze as the final push of deeper moisture works through the area. Frequency and persistence of MVFR is now expected to gradually decrease through the remainder of the morning. Elsewhere, locally breezy trades will focus occasional showers and low clouds over windward and mauka zones with nothing more than localized MVFR expected.
AIRMET Sierra for mountain obscuration over Windward Big Island remains in effect.
AIRMET Tango for lee turbulence remains in effect.

Marine

A high pressure system far north of the Hawaiian Islands continues to produce moderate to locally strong trade winds over the region. A Small Craft Advisory (SCA) remains in effect for windier waters around Maui and the Big Island. Wind speeds may briefly drop below SCA thresholds tonight through Wednesday morning, due to a passing surface trough, however winds will ramp back up into the SCA range quickly from late Wednesday onward as the surface trough fades.
Small surf will continue for all islands into the weekend. East facing shores will see increasing surf height trends by the end of the week as trade wind speeds increase from Thursday onward. North facing shores will see small north to northwest swells keeping small to fun size surf in the forecast through Saturday. South facing shores will see a few long period south swells moving up from the South Pacific, keeping surf heights elevated through the week. West facing shores will see small northwest and south swell wave wrap.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST this evening for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov