Hilo

Today: Mostly cloudy with scattered showers. Highs 76 to 87 near the shore to around 69 at 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with numerous showers. Lows 64 to 71 near the shore to around 57 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 70 percent.

Tuesday: Mostly cloudy. Numerous showers in the morning, then isolated showers in the afternoon. Highs 76 to 87 near the shore to around 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Kona

Today: Partly sunny with isolated showers. Highs 83 to 89 near the shore to around 70 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows around 75 near the shore to 50 to 56 near 5000 feet. Light winds. Chance of rain 20 percent.

Tuesday: Mostly cloudy with isolated showers. Highs 82 to 88 near the shore to around 69 near 5000 feet. Southwest winds up to 10 mph. Chance of rain 20 percent.

Waimea

Today: Mostly cloudy with scattered showers. Highs 66 to 85. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 64 to 71 near the shore to around 60 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Mostly cloudy. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 72 to 81 near the shore to 67 to 80 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Kohala

Today: Mostly cloudy with scattered showers. Highs 66 to 85. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 64 to 71 near the shore to around 60 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Mostly cloudy. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 72 to 81 near the shore to 67 to 80 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

South Big Island

Today: Partly sunny. Breezy. Highs around 86 near the shore to around 67 near 5000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon.

Tonight: Mostly cloudy. Lows around 73 near the shore to around 52 near 5000 feet. Northeast winds up to 15 mph.

Tuesday: Partly sunny. Breezy. Highs around 86 near the shore to around 67 near 5000 feet. East winds up to 20 mph.

Puna

Today: Mostly cloudy with scattered showers. Highs 76 to 87 near the shore to around 69 at 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with numerous showers. Lows 64 to 71 near the shore to around 57 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 70 percent.

Tuesday: Mostly cloudy. Numerous showers in the morning, then isolated showers in the afternoon. Highs 76 to 87 near the shore to around 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Waikoloa

Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs 84 to 90 near the shore to 67 to 74 above 4000 feet. Northeast winds up to 20 mph.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Lows around 75 near the shore to 53 to 58 above 4000 feet. Southeast winds up to 20 mph.

Tuesday: Mostly sunny in the morning then becoming mostly cloudy. Breezy. Highs 84 to 89 near the shore to 66 to 73 above 4000 feet. Northeast winds up to 20 mph.

Detailed Forecast

Synopsis

High pressure far north of the Hawaiian Islands will gradually weaken and slowly drift west over the next several days. Moderate to locally breezy trade winds will continue into Tuesday, then weaken slightly Wednesday through the rest of the week. Stable conditions across the region will focus showers mainly along windward and mauka areas, particularly during the overnight and early morning hours.

Discussion

Satellite imagery and radar imagery show clouds and showers have picked up overnight with the diurnal cycle. Expect typical summertime trade wind weather this week, with clouds and showers favoring windward and mauka areas during the overnight and early morning hours. Leewards areas will remain mostly dry, except the kona slopes on the Big Island could see some brief afternoon/evening sea breeze showers. Hi res models are hinting at a band of showers moving through the island chain along with breezy winds tonight that could provide a boost in showers mainly along windward and mauka areas. Guidance remains on track keeping the base of the inversion around 4,000-6,000 feet this week. This will help to limit vertical cloud development resulting in a decrease in clouds and showers across the state, especially during the second half of the week.
Latest model guidance maintains moderate to locally breezy trade winds through into Tuesday. A low pressure area is expected to develop far northeast of the state Tuesday which could weaken the gradient over the state, allowing for moderate trade winds to develop Wednesday through the rest of the week. May see breezy trade winds return late over the weekend and into early next week.

Aviation

Breezy trades are expected to continue today and tonight. Mostly dry conditions are expected today, with only a few showers affecting windward locales. We should see an increase in trade wind showers tonight as a band of enhanced moisture moves through. Predominantly VFR conditions should prevail today, with some MVFR cigs/vsbys becoming more likely tonight across windward areas as the band of enhanced moisture moves through.
AIRMET Tango remains in effect for moderate low level turbulence over and downwind of the terrain of all islands. This AIRMET will likely continue through the day.

Marine

Strong surface high pressure north of the state will maintain fresh to locally strong trades into the first half of this week. A Small Craft Advisory (SCA) was extended in time this morning to run through Tuesday afternoon for the typical windier areas around Maui and the Big Island. Trade winds will decrease into the gentle to fresh range by late Tuesday or by Wednesday as the the high center drifts farther west and a cut off low deepens far northeast of the state.
A small long period south-southwest swell (200 degrees) will arrive this afternoon, briefly bumping up south and west shore surf heights into Tuesday, and then surf heights will slowly decline with the swell through Wednesday.
Surf along east facing shores will remain choppy with short period wind waves before slowly declining with the trade winds through Wednesday. A tiny background west-northwest swell will arrive late Tuesday into Wednesday providing a small bump for north facing shores.

Fire weather

Locally breezy trade winds and low relative humidity will keep elevated fire weather concerns over leeward areas through Tuesday. Locations such as West Maui and leeward Kohala on the Big Island are of particular concern. Trade winds should weaken to moderate levels Wednesday as the pressure gradient relaxes over the state then hold through the rest of the week.
Most leeward areas will remain dry. Brief periods of showers may impact windward and mauka areas. Expect good to excellent overnight recoveries at lower elevations. The exception will continue to be near the inversion between 4,000-8,000 feet where periods of warmer temperatures with much drier conditions are possible through much of the upcoming week.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov