Hilo

Tonight: Mostly cloudy with numerous showers. Lows 61 to 69 near the shore to 52 to 58 at 4000 feet. North winds up to 10 mph shifting to the west after midnight. Chance of rain 70 percent.

Tuesday: Mostly cloudy. Numerous showers early in the morning, then scattered showers in the late morning and afternoon. Highs 78 to 83 near the shore to around 67 at 4000 feet. South winds up to 10 mph shifting to the southeast in the afternoon. Chance of rain 60 percent.

Tuesday Night: Mostly cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Lows 61 to 70 near the shore to 53 to 58 at 4000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Kona

Tonight: Mostly cloudy with isolated showers until early morning, then partly cloudy late in the night. Lows around 72 near the shore to 49 to 54 near 5000 feet. Light winds. Chance of rain 20 percent.

Tuesday: Mostly sunny early in the morning, then partly sunny with scattered showers in the late morning and afternoon. Highs 82 to 87 near the shore to around 67 near 5000 feet. West winds up to 10 mph. Chance of rain 30 percent.

Tuesday Night: Partly cloudy. Scattered showers early in the evening. Lows around 72 near the shore to 49 to 54 near 5000 feet. Light winds. Chance of rain 30 percent.

Waimea

Tonight: Mostly cloudy with scattered showers. Lows 62 to 71 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tuesday: Partly sunny with scattered showers. Highs around 80 near the shore to 69 to 76 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tuesday Night: Mostly cloudy with scattered showers early in the evening, then partly cloudy with isolated showers in the late evening and overnight. Lows 62 to 71 near the shore to 55 to 62 near 3000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Kohala

Tonight: Mostly cloudy with scattered showers. Lows 62 to 71 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tuesday: Partly sunny with scattered showers. Highs around 80 near the shore to 69 to 76 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tuesday Night: Mostly cloudy with scattered showers early in the evening, then partly cloudy with isolated showers in the late evening and overnight. Lows 62 to 71 near the shore to 55 to 62 near 3000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

South Big Island

Tonight: Partly cloudy. Breezy. Isolated showers until early morning. Lows around 74 near the shore to around 55 near 5000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Highs around 85 near the shore to around 66 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tuesday Night: Partly cloudy with isolated showers. Lows around 74 near the shore to around 55 near 5000 feet. East winds around 10 mph. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with numerous showers. Lows 61 to 69 near the shore to 52 to 58 at 4000 feet. North winds up to 10 mph shifting to the west after midnight. Chance of rain 70 percent.

Tuesday: Mostly cloudy. Numerous showers early in the morning, then scattered showers in the late morning and afternoon. Highs 78 to 83 near the shore to around 67 at 4000 feet. South winds up to 10 mph shifting to the southeast in the afternoon. Chance of rain 60 percent.

Tuesday Night: Mostly cloudy. Scattered showers early in the evening, then isolated showers in the late evening and overnight. Lows 61 to 70 near the shore to 53 to 58 at 4000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Waikoloa

Tonight: Partly cloudy with isolated showers. Lows around 73 near the shore to 51 to 56 above 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Tuesday: Sunny with isolated showers early in the morning, then partly sunny with scattered showers in the late morning and afternoon. Highs around 84 near the shore to around 68 above 4000 feet. West winds up to 10 mph. Chance of rain 40 percent.

Tuesday Night: Partly cloudy. Scattered showers early in the evening. Lows 70 to 75 near the shore to 51 to 56 above 4000 feet. West winds up to 10 mph in the evening becoming light. Chance of rain 40 percent.

Detailed Forecast

Synopsis

Moderate easterly trade winds will ease Tuesday as the surface ridge weakens, bringing a transition to light winds, increasing humidity, and land and sea breeze conditions through Thursday. Showers will remain brief and mainly over interior and leeward areas during the afternoons. Rainfall chances may increase by next weekend as an upper disturbance and a weak front approach the islands.

Discussion

Moderate easterly trades will remain in place through much of the overnight hours, with low clouds and a few light showers focused over windward and mauka areas. Leeward areas will remain mostly dry, with only isolated passing showers possible.
Beginning late tonight or early Tuesday, the ridge north of the islands will weaken in response to a series of cold fronts passing well north of the state. This will lead to a gradual easing of the trade winds, with local land and sea breeze circulations becoming more dominant through midweek. From Tuesday through midweek, a more humid air mass will settle over the islands, with dewpoints potentially climbing into the mid- to upper-60s. These dewpoints combined with the afternoon sea breezes will support localized afternoon cloud buildups and a few brief showers over interior and leeward areas, followed by clearing at night as land breezes develop.
By the latter part of the week into the weekend, moisture and rainfall chances may trend up. Global guidance indicates upper heights lowering as an upper-level disturbance approaches the region. In addition, a weak attendant frontal boundary may move into the area. However, there remains considerable spread among the model solutions regarding the timing and strength of these features, so confidence in the details remains limited at this time.

Aviation

Moderate trade winds will deliver showers over windward and mountain areas through this evening before weakening overnight. Light winds tomorrow will allow a land and sea breeze pattern to take place with possible afternoon showers over island interiors. Periods of MVFR ceilings and visibility are possible in showers, otherwise VFR is expected.
AIRMET Sierra is currently in effect for mountain obscuration over windward areas of Maui, but expect conditions to improve overnight. No other AIRMET's are in effect.

Marine

High pressure northeast of the state will drive moderate to fresh trades tonight. The trades will ease and shift southeasterly at light to moderate levels Tuesday and Tuesday night as an approaching front merges with a trough north of the island chain. the trough will weakening front will pass north of the area on Wednesday, bringing light and variable winds, with sea and land breezes present near the immediate coasts. A new high building northwest of the state will bring a return of light to moderate trades Thursday and Friday, with the trades strengthening to moderate and fresh levels over the weekend. Winds and seas are expected to remain below Small Craft Advisory thresholds through at least Friday.
A moderate medium-period northwest swell will gradually lower during the next couple of days. A new long period swell will build Wednesday night and give a nice boost to north and west shore surf Thursday and Friday, followed by a gradual decline over the weekend into early next week.
A series of overlapping south swells will keep steady small surf rolling into south facing shores during the next week.
Surf along east facing shores will remain below normal during the next 7 days due to the lack of strong trades over and upstream of the islands.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov