Photo Credit: James Grenz

Hilo

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 80 to 85 near the shore to around 70 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 60 percent.

Tonight: Mostly cloudy. Numerous showers in the evening, then scattered showers after midnight. Lows 65 to 70 near the shore to around 54 at 4000 feet. Northeast winds around 10 mph shifting to the southwest up to 10 mph after midnight. Chance of rain 60 percent.

Wednesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 80 to 85 near the shore to around 70 at 4000 feet. Southeast winds up to 10 mph shifting to the east in the afternoon. Chance of rain 70 percent.

Kona

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 82 to 87 near the shore to around 73 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 71 near the shore to around 54 near 5000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Mostly sunny. Scattered showers in the afternoon. Highs around 85 near the shore to around 72 near 5000 feet. South winds up to 10 mph shifting to the west around 10 mph in the afternoon. Chance of rain 50 percent.

Waimea

Today: Breezy. Partly sunny with scattered showers. Highs 65 to 84. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 68 near the shore to 54 to 63 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 66 to 86. East winds 10 to 15 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Partly sunny with scattered showers. Highs 65 to 84. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 68 near the shore to 54 to 63 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 66 to 86. East winds 10 to 15 mph. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny with isolated showers. Highs around 84 near the shore to around 68 near 5000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 69 to 75 near the shore to around 52 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Sunny and breezy. Isolated showers in the afternoon. Highs around 84 near the shore to around 69 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 80 to 85 near the shore to around 70 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 60 percent.

Tonight: Mostly cloudy. Numerous showers in the evening, then scattered showers after midnight. Lows 65 to 70 near the shore to around 54 at 4000 feet. Northeast winds around 10 mph shifting to the southwest up to 10 mph after midnight. Chance of rain 60 percent.

Wednesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 80 to 85 near the shore to around 70 at 4000 feet. Southeast winds up to 10 mph shifting to the east in the afternoon. Chance of rain 70 percent.

Waikoloa

Today: Breezy. Mostly sunny with isolated showers. Highs 81 to 88 near the shore to 68 to 74 above 4000 feet. Northeast winds up to 25 mph. Chance of rain 20 percent.

Tonight: Mostly clear with isolated showers. Lows around 73 near the shore to 51 to 59 above 4000 feet. East winds 10 to 15 mph decreasing to up to 10 mph after midnight. Chance of rain 20 percent.

Wednesday: Sunny. Highs 82 to 89 near the shore to 67 to 73 above 4000 feet. Northeast winds up to 10 mph shifting to the northwest around 10 mph in the afternoon. Gusts up to 30 mph.

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.

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Data Courtesy of NOAA.gov