Photo Credit: James Grenz

Hilo

Today: Partly sunny with scattered showers. Highs around 83 near the shore to 70 to 76 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows around 67 near the shore to around 53 at 4000 feet. Northwest winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Friday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 83 near the shore to 70 to 76 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 40 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 83 to 88 near the shore to 68 to 75 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Lows around 74 near the shore to 53 to 59 near 5000 feet. Light winds. Chance of rain 20 percent.

Friday: Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs 83 to 88 near the shore to 68 to 75 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Waimea

Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 83 near the shore to around 75 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 68 near the shore to around 57 near 3000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 83 near the shore to around 75 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Kohala

Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 83 near the shore to around 75 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 68 near the shore to around 57 near 3000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 83 near the shore to around 75 near 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Big Island

Today: Breezy. Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 86 near the shore to around 68 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 69 near the shore to around 53 near 5000 feet. North winds up to 15 mph. Chance of rain 20 percent.

Friday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 86 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny with scattered showers. Highs around 83 near the shore to 70 to 76 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows around 67 near the shore to around 53 at 4000 feet. Northwest winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Friday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 83 near the shore to 70 to 76 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 40 percent.

Waikoloa

Today: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to 68 to 78 above 4000 feet. North winds up to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Lows 68 to 73 near the shore to 53 to 60 above 4000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Friday: Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 84 near the shore to 68 to 78 above 4000 feet. Southeast winds up to 10 mph shifting to the north in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Moderate trade winds will ease slightly for Friday and weekend, then pick up to moderate strength again early next week. The stable trade winds will focus showers over windward slopes, and leeward Big Island slopes will continue to experience afternoon clouds and scattered showers. As trades weaken, leeward areas from Maui to Kauai will see afternoon clouds, though showers will be sparse.

Discussion

Stable trade wind weather remains in place. A surface ridge far north of Kauai is driving the moderate trade winds, and a ridge aloft is providing stable conditions with a firm inversion based between 4,500 to 6,000 ft. Due to a slot of relatively dry air in the trade wind flow, it has been rather dry overnight, but an area of modest showers will move in later this morning and mainly affect windward areas.
Stable conditions will persist through the week, but trade winds drop slightly for Friday and the weekend as the surface ridge is nudged closer to the state. The windward rainfall pattern will be unchanged and largely dependent on shallow pockets of moisture moving within the trade wind flow. Leeward Big Island slopes will experience afternoon clouds and showers, but when trade winds are suppressed, leeward terrain from Maui to Kauai will see a greater amount of afternoon clouds, though rainfall will be scant.

Aviation

Early this morning, VFR flight conditions are prevailing statewide with latest satellite and radar imagery depicting only isolated low clouds and showers. Moderate easterly trade wind flow will continue today across the island chain, allowing showers and clouds to favor windward locations. Additionally, the leeward slopes of the Big Island will see an increase in cloud cover again this afternoon before clearing late tonight or early Friday morning. Looking ahead, trade wind speeds will drop slightly heading into Friday and the weekend, which could allow for land and sea breezes to form in sheltered areas.
There are currently no AIRMETs in effect. However, tempo mountain obscuration may become an issue later today as models suggest that a band of moisture approaching from the east could result in an uptick in shower activity and MVFR cigs, especially across windward sections of Maui and the Big Island.

Marine

An east-to-west oriented surface ridge well north of the islands is currently supporting moderate to locally fresh trade winds. The ridge will weaken and move south over the next day or two as a front passes well north of the area. This will result in a weakening of the flow, with light to moderate trades prevailing through the weekend. The potential exists for winds to remain weaker than normal into at least the middle of next week as the ridge remains nearby. Aside from localized diurnal changes in wind speeds, conditions are expected to remain below Small Craft Advisory levels in all zones.
A significant long-period south swell will gradually subside over the next day or so, and the High Surf Advisory (HSA) for south facing shores that had been in effect has been cancelled. Surf is expected to lower further today, but modest reinforcements from the southern hemisphere will maintain surf heights near the seasonal average along south facing shores into next week. Elsewhere, surf will remain below HSA levels. A couple of small swells from the north and northwest will arrive from Friday into next week, keeping surf from becoming completely flat along north facing shores. Weak trade winds near and upstream of the islands will deliver small short-period wind waves to east facing shores.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov