Hilo

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 86 near the shore to 69 to 75 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Showers likely in the evening, then occasional showers after midnight. Lows around 70 near the shore to around 56 at 4000 feet. North winds up to 10 mph shifting to the west after midnight. Chance of rain 90 percent.

Saturday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs around 86 near the shore to 69 to 75 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 82 to 87 near the shore to around 69 near 5000 feet. Light winds. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows around 73 near the shore to around 57 near 5000 feet. Light winds. Chance of rain 50 percent.

Saturday: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 82 to 87 near the shore to around 69 near 5000 feet. Light winds. Chance of rain 50 percent.

Waimea

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to 69 to 80 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows around 70 near the shore to 58 to 64 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 84 near the shore to 69 to 80 near 3000 feet. East winds up to 20 mph. Chance of rain 70 percent.

Kohala

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to 69 to 80 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows around 70 near the shore to 58 to 64 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 84 near the shore to 69 to 80 near 3000 feet. East winds up to 20 mph. Chance of rain 70 percent.

South Big Island

Today: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 86 near the shore to around 73 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Lows around 72 near the shore to around 55 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Saturday: Breezy. Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 86 near the shore to around 73 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Puna

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 86 near the shore to 69 to 75 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Showers likely in the evening, then occasional showers after midnight. Lows around 70 near the shore to around 56 at 4000 feet. North winds up to 10 mph shifting to the west after midnight. Chance of rain 90 percent.

Saturday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs around 86 near the shore to 69 to 75 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Waikoloa

Today: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 86 near the shore to 70 to 76 above 4000 feet. Northeast winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 74 near the shore to 53 to 60 above 4000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Saturday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 86 near the shore to 70 to 76 above 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Light to moderate trades will prevail today through Saturday, allowing localized land and sea breezes to develop in the more sheltered leeward areas. Drier weather will overspread the islands today, with an increase in trade wind showers then expected tonight through early Sunday as an area of enhanced moisture moves from east to west across the state. Drier conditions and moderate trades will return by Sunday afternoon and hold through the first half of Labor Day. Another round of increased showers could move through later on Labor Day and continue into early Tuesday. Drier conditions and moderate trades are then forecast Tuesday afternoon through Thursday.

Discussion

Currently at the surface, a weakening stationary front is located around 200 miles north of Kauai, while a ridge is positioned around 800 miles north of the Garden Isle. The ridging has weakened a bit since last evening, with light to moderate trade winds now prevailing across the island chain. Infrared satellite imagery shows partly to mostly cloudy skies across the state, with cloud coverage the highest over the central islands. Radar imagery shows scattered to numerous showers across Maui County and Oahu, with less shower activity over Kauai and the Big Island. Main short term focus revolves around trade wind trends and rain chances during the next few days.
The front north of the islands will gradually dissipate today. A trough will develop along the old frontal remnants over the weekend, and slide by a couple hundred miles north of the state on Sunday. Otherwise, surface ridging will remain the dominant weather feature to the north of the islands during the next 7 days. Light to moderate trades will prevail today through Saturday, with localized land and sea breezes in the more sheltered leeward areas. The trades should strengthen back to moderate levels on Sunday, and hold generally at moderate levels through much of next week.
As for the remaining weather details, after some morning showers, a drier airmass looks to overspread the state by mid to late morning and hold in place through the afternoon, keeping shower activity rather sparse in most areas. An area of deeper moisture then appears to slide from east to west through the islands tonight through Sunday morning, which should bring an increase in trade wind showers, particularly to windward slopes and coasts, and perhaps some more leeward and interior shower development Saturday afternoon. A drier trade wind pattern should then return Sunday afternoon through the morning hours of Labor Day. The next area of deeper moisture appears to slide from east to west through the islands later Labor Day through early Tuesday, with a return to a drier trade wind pattern Tuesday afternoon through Thursday.

Aviation

Early this morning, a band of moisture is moving across the central islands from Oahu to Maui. This has increased shower activity and cloud coverage, though ceilings have generally ranged from 6,000 to 7,500 feet with VFR conditions prevailing at most locations.
A weak front north of the islands will maintain moderate trade winds for the next couple of days. This will allow localized sea breezes to develop over leeward areas of the smaller islands again this afternoon, increasing interior cloud cover and shower activity. The Kona slopes of the Big Island will experience sea breezes and enhanced clouds/showers later today as well. Clouds and showers will diminish for leeward locations overnight, favoring windward and mountain areas. Regardless, VFR conditions will prevail for most locations over the next 24 hours with only brief MVFR conditions possible in passing trade showers.
There are currently no AIRMETs in effect, and none are expected at this time.

Marine

Moderate to fresh easterly trades will persist through Saturday, then strengthen into the fresh to strong category Sunday into early next week as high pressure builds to the north.
Surf along south facing shores will remain small through next week with mainly reinforcing shots of south and south-southwest background level swells moving through. The next small source will arrive over the weekend out of the south-southwest, likely enough to keep the surf from going flat. For the extended, a decent south-southwest swell could arrive locally next weekend (around the 10th), depending on how the source evolves as it passes south of the Tasman Sea and New Zealand this weekend.
Surf along north facing shore will remain small through next week, with mainly the small north-northeast medium period energy continuing due to the deep troughing and systems in/near the Gulf of Alaska. Guidance does show a compact low moving eastward over the western Aleutians this weekend with a batch of fresh breezes setting up within the 330-340 directional band relative to the islands. If this materializes, a small north-northwest swell could arrive by next Thursday.
Surf along east facing shores will remain well below seasonal average into next week.

HFO Watches/Warnings/Advisories

None.

Big Island Now Weather is brought to you by Blue Hawaiian Helicopters.

Check out their Big Island Helicopter Tours today!

Data Courtesy of NOAA.gov