Hilo

Tonight: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 62 to 70 near the shore to 52 to 57 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 79 to 86 near the shore to 64 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Sunday Night: Cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 64 to 70 near the shore to 54 to 59 at 4000 feet. West winds up to 10 mph. Chance of rain 70 percent.

Kona

Tonight: Partly cloudy with isolated showers. Lows around 73 near the shore to 48 to 54 near 5000 feet. Light winds. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs 83 to 88 near the shore to 65 to 70 near 5000 feet. Southwest winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.

Sunday Night: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 73 near the shore to 48 to 54 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Partly cloudy with isolated showers. Lows 62 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs 65 to 84. East winds up to 15 mph. Chance of rain 20 percent.

Sunday Night: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 64 to 71 near the shore to 56 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Kohala

Tonight: Partly cloudy with isolated showers. Lows 62 to 71 near the shore to 54 to 61 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs 65 to 84. East winds up to 15 mph. Chance of rain 20 percent.

Sunday Night: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 64 to 71 near the shore to 56 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

South Big Island

Tonight: Partly cloudy. Breezy. Lows around 73 near the shore to around 52 near 5000 feet. Northeast winds up to 20 mph.

Sunday: Mostly sunny. Breezy. Highs around 85 near the shore to around 67 near 5000 feet. East winds up to 20 mph.

Sunday Night: Partly cloudy. Lows around 74 near the shore to around 52 near 5000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph after midnight.

Puna

Tonight: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 62 to 70 near the shore to 52 to 57 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 79 to 86 near the shore to 64 to 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Sunday Night: Cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 64 to 70 near the shore to 54 to 59 at 4000 feet. West winds up to 10 mph. Chance of rain 70 percent.

Waikoloa

Tonight: Partly cloudy. Lows around 73 near the shore to 51 to 56 above 4000 feet. Southeast winds up to 15 mph.

Sunday: Sunny and breezy. Highs 83 to 89 near the shore to 65 to 73 above 4000 feet. Northeast winds up to 20 mph.

Sunday Night: Partly cloudy. Isolated showers after midnight. Lows around 74 near the shore to 51 to 56 above 4000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate trades deliver limited showers to windwad and mauka areas through Sunday followed by a slight uptick in shower coverage Sunday night into Monday. Trades then strengthen slightly through mid-week.

Discussion

A weak surface ridge axis aligned along the 30th parallel drives dry, moderate trades across the islands at press time. Observed soundings confirm dry boundary layer conditions beneath a building mid-level ridge, and this will be the case for at least the next 24 hours. Southwesterlies aloft will transport high clouds across area skies through the weekend, though coverage will steadily diminish as the parent low drifts west and ridging builds.
A narrow ribbon of moisture upstream of the islands extends southeastward from about 145W/20N. Visible satellite indicates improved saturation compared to yesterday, and guidance maintains a good handle on its position and gradual westward progress. A brief uptick in trade wind showers is anticipated as this band of moisture advances through the islands Sunday night into Monday, but rainfall amounts are likely to remain limited given rather unimpressive satellite presentation and antecedent hostile/dry environment. Upper ridging amplifies over the eastern Pacific through mid-week bringing a return of breezy trades late Monday through Wednesday or Thursday.

Aviation

Light to moderate trades will continue for another day or so. Scattered clouds and mainly isolated showers will favor windward and mountain areas, particularly through the overnight and early morning hours. In this lighter wind pattern, sea breezes will also bring afternoon clouds and isolated showers to some leeward interior areas, followed by clearing overnight with land breezes. Aside from brief MVFR conditions in isolated showers, VFR will prevail across the island chain.
No AIRMETs are currently in effect and none are expected through the next 24 hours.

Marine

A series of cold fronts passing across the North Pacific is displacing high pressure north of the islands and resulting in gentle to locally moderate trade winds. These gentle to moderate trades will hold through the rest of the weekend. High pressure will reestablish itself over the eastern Pacific by Monday, bringing trades back into the moderate to locally fresh categories. Winds could increase a bit more by Tuesday, becoming locally strong across the typically windier waters of Maui County and the Big Island. By late next week, a weakening pressure gradient will allow trades to weaken once again.
Buoys show that a small, medium period (roughly 2-3 feet, 11 seconds) north swell is moving through the islands. This will keep small surf across north-facing shores through Sunday. However, the arrival of a new, moderate long period north (350 degree) swell Sunday night or early Monday morning will likely produce advisory level surf along north-facing shores. This swell will peak Monday evening and then slowly decline through mid week.
A small, long period south (180 degree) reinforcement continues to hold, producing waist to chest-high surf along south-facing shores. South shore surf will slowly decrease through early next week as this reinforcement fades.
Surf along west-facing shores will remain elevated, influenced by both the north and south swell wrap. East-facing shore wind wave chop will remain relatively small under the relatively weak trade wind regime.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov