Hilo

Today: Mostly cloudy with scattered showers. Highs 82 to 88 near the shore to around 70 at 4000 feet. South winds up to 10 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with showers likely. Lows 66 to 73 near the shore to around 54 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 70 percent.

Thursday: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 82 to 88 near the shore to around 70 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Kona

Today: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 81 to 86 near the shore to 67 to 72 near 5000 feet. North winds up to 10 mph shifting to the west in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy. Scattered showers in the evening. Lows 68 to 73 near the shore to around 54 near 5000 feet. Light winds. Chance of rain 40 percent.

Thursday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 81 to 86 near the shore to 67 to 72 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 82 near the shore to 74 to 80 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 56 to 62 near 3000 feet. East winds up to 15 mph increasing to 10 to 20 mph after midnight. Chance of rain 50 percent.

Thursday: Mostly cloudy. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82 near the shore to 74 to 80 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Kohala

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 82 near the shore to 74 to 80 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 56 to 62 near 3000 feet. East winds up to 15 mph increasing to 10 to 20 mph after midnight. Chance of rain 50 percent.

Thursday: Mostly cloudy. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82 near the shore to 74 to 80 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 74 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Lows around 69 near the shore to around 53 near 5000 feet. Northeast winds up to 20 mph.

Thursday: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 74 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Puna

Today: Mostly cloudy with scattered showers. Highs 82 to 88 near the shore to around 70 at 4000 feet. South winds up to 10 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with showers likely. Lows 66 to 73 near the shore to around 54 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 70 percent.

Thursday: Cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 82 to 88 near the shore to around 70 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. Highs 82 to 87 near the shore to 68 to 75 above 4000 feet. East winds up to 10 mph shifting to the northwest in the afternoon.

Tonight: Partly cloudy. Lows around 72 near the shore to 51 to 58 above 4000 feet. Southeast winds up to 15 mph.

Thursday: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs 82 to 87 near the shore to 68 to 75 above 4000 feet. Northeast winds up to 25 mph.

Detailed Forecast

Synopsis

Light winds and humid conditions will continue today, with clouds and showers favoring interior and leeward areas through the afternoon hours. Breezy trade wind conditions will return tonight through the second half of the week, shifting clouds and showers back to the typical windward and mauka locations. Trades may ease late in the weekend through early next week as an upper disturbance moves into the area.

Discussion

The land and sea breeze regime with a light east to southeast background flow in place will continue today as an upper low and surface trough continue westward and away from the region. This combined with a slug of moisture clipping the islands from east to west will support humid conditions today, along with another round of afternoon showers where sea breezes develop. Recent satellite-derived precipitable water (PW) data reflected this area of higher moisture (2″ PWs) lurking south of the Big Island this morning.
Near-term guidance remains consistent and depicts a drying trend through the second half of the week as upper heights rise and the surface ridge builds to the north. Breezy trades combined with lowering dewpoints will be the result. Clouds and showers will shift back to the typical windward and mauka locations, with the best coverage overnight though the morning periods as pockets of moisture move through.
The long-term guidance depicts the pressure gradient loosening once again late in the weekend and into early next week as an upper low moves in and a weakness forms in the subtropical ridge to the north. If this materializes, trades will become disrupted with another land and sea breeze pattern setting up.

Aviation

Trade winds will return later today with localized sea breezes lingering along western terrain sheltered slopes. Convergence boundaries between the trade winds and daytime sea breezes will produce showers over leeward areas. Otherwise the returning trade wind regime will shift cloud and shower activity back to windward and mountain areas favoring the overnight to early morning hours. Brief MVFR is possible with shower activity.
No AIRMETs in effect and none are expected.

Marine

The weak trough north of the islands that has recently disrupted trade flow and introduced several days of light winds will be moving west of the area through the day. This will allow high pressure centered far northeast of the state to assert more of an influence through late week. The tighter pressure gradient produced from this high will reawaken more areawide moderate to locally strong trade winds from early Thursday into the Labor Day Weekend. Trades will likely be strong enough over the typically windier areas surrounding Maui County and south of Big Island Thursday to warrant a Small Craft Advisory (SCA). Trades are expected to further strengthen on Friday which could support the expansion of the SCA.
A very small, medium period south swell will be reinforced by small, slightly longer period south and low period southeast swells the next several days. These swells will lift and maintain seasonal south facing shore surf late this week. Strengthened trades over and upstream of the chain will bring in a higher wind wave east swell. This will build east facing shore surf to near normal levels from Thursday through the weekend.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov