Hilo

Tonight: Mostly cloudy with scattered showers. Lows 62 to 69 near the shore to 48 to 56 at 4000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Thursday: Partly sunny with scattered showers. Highs 78 to 83 near the shore to around 67 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Thursday Night: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 61 to 69 near the shore to 49 to 56 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Kona

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Haze through the night. Lows around 72 near the shore to 45 to 51 near 5000 feet. Light winds. Chance of rain 50 percent.

Thursday: Partly sunny with isolated showers. Haze. Highs 83 to 88 near the shore to around 66 near 5000 feet. Southwest winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.

Thursday Night: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Haze through the night. Lows around 71 near the shore to 45 to 51 near 5000 feet. Light winds. Chance of rain 30 percent.

Waimea

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 61 to 70 near the shore to 52 to 60 near 3000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Thursday: Mostly sunny. Breezy. Isolated showers in the morning. Highs around 79 near the shore to 70 to 78 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Thursday Night: Mostly clear. Breezy. Isolated showers in the evening. Lows 61 to 70 near the shore to 52 to 61 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Kohala

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 61 to 70 near the shore to 52 to 60 near 3000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Thursday: Mostly sunny. Breezy. Isolated showers in the morning. Highs around 79 near the shore to 70 to 78 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Thursday Night: Mostly clear. Breezy. Isolated showers in the evening. Lows 61 to 70 near the shore to 52 to 61 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

South Big Island

Tonight: Breezy. Mostly cloudy with scattered showers in the evening, then mostly clear after midnight. Haze through the night. Lows around 72 near the shore to around 50 near 5000 feet. Northeast winds up to 20 mph. Chance of rain 50 percent.

Thursday: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny in the afternoon. Haze through the day. Highs around 86 near the shore to around 66 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Breezy. Isolated showers in the evening. Haze through the night. Lows around 72 near the shore to around 49 near 5000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with scattered showers. Lows 62 to 69 near the shore to 48 to 56 at 4000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Thursday: Partly sunny with scattered showers. Highs 78 to 83 near the shore to around 67 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Thursday Night: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 61 to 69 near the shore to 49 to 56 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear after midnight. Lows 69 to 74 near the shore to 47 to 53 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Thursday: Breezy. Mostly sunny with isolated showers. Highs 82 to 89 near the shore to 65 to 71 above 4000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Thursday Night: Mostly clear. Breezy. Lows 69 to 74 near the shore to 47 to 53 above 4000 feet. East winds up to 20 mph.

Detailed Forecast

Synopsis

Trade winds have developed across the state this afternoon, but remain light enough for some sea breeze clouds and showers over leeward and sheltered areas. Trade winds will strengthen to moderate to locally breezy by Friday and continue into early next week, with clouds and showers favoring windward and mauka areas.

Discussion

Light trade winds have developed across the state this afternoon as a weak surface trough north of Kauai continues to dissipate and surface high pressure builds far northeast of the islands. Radar and satellite imagery shows scattered clouds and showers over leeward and sheltered areas due to weak sea breezes. Some of these showers have been pushed offshore by the developing trades and the lingering showers should dissipate later this evening. Trades will continue to gradually strengthen across the islands tonight, with stable conditions developing as a mid-level ridge builds overhead. Moderate to locally breezy trades are expected to return Friday then hold through early next week as a pair of strong high pressure systems move north of the state. With the return of stable trade wind conditions expect clouds and showers to favor windward and mauka areas, particularly during the overnight and early morning hours.
Also, as trades become reestablished across the state expect vog to slowly shift away from the smaller islands.

Aviation

Limited showers this afternoon as returning trades prevented the sea breeze from establishing. What few interior/leeward showers exist will dissipate with the loss of diurnal heating this afternoon. Locally breezy trade winds then prevail focusing clouds and showers windward and mauka. VFR anticipated with nothing more than spotty MVFR within any heavier showers.
No AIRMETs in effect.

Marine

High pressure will build far north of the state through Friday then gradually move eastward over the weekend. Trade winds should steadily strengthen on Thursday with fresh to locally strong trades expected by Thursday afternoon for the typical windy areas around Maui County and the Big Island. Trade winds will likely strengthen a touch on Friday with widespread fresh to locally strong trade winds through the weekend. Small Craft Advisory (SCA) should return to the typical windy areas around Maui County and the Big Island on Thursday.
Starting tonight, a moderate to long period north-northwest swell is expected to arrive, producing surf above the seasonal average. Buoy 51001 northwest of Kauai is starting to show long-period forerunners this afternoon. This north- northwest swell should peak late Thursday then slowly decline over the weekend. A series of northwest to north swells are expected next week which should produce surf near or above the seasonal average (6 feet for the month of May).
A new long-period south-southwest swell will continue to fill in tonight and peak Thursday into Friday with surf heights above the summer average then slowly fade into the weekend. However, a mix of reinforcing south- southwest swell and new south-southeast swell energy will arrive this weekend and should help maintain surf near or above the summer average (5 feet). Surf will generally decline next week, but smaller swells from the south- southwest should maintain surf near the summer average through the middle of next week.
Weak upstream trade wind flow will keep surf on the small side for east facing shores. An increase is expected on Friday as the trade winds strengthen a notch. Rough and choppy surf is expected along east facing shores Friday through the weekend.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov