Hilo

Today: Breezy. Partly sunny with scattered showers. Highs 79 to 84 near the shore to around 70 at 4000 feet. Northeast winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Numerous showers in the evening, then occasional showers after midnight. Lows 63 to 71 near the shore to around 56 at 4000 feet. North winds up to 15 mph. Chance of rain 80 percent.

Saturday: Mostly cloudy. Occasional showers in the morning, then numerous showers in the afternoon. Highs 77 to 84 near the shore to around 67 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 90 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 83 to 88 near the shore to around 70 near 5000 feet. Light winds. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear with isolated showers after midnight. Lows around 73 near the shore to around 52 near 5000 feet. Light winds. Chance of rain 40 percent.

Saturday: Sunny in the morning, then mostly cloudy with numerous showers in the afternoon. Highs around 86 near the shore to around 69 near 5000 feet. Light winds. Chance of rain 70 percent.

Waimea

Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 64 to 85. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 63 to 71 near the shore to 56 to 63 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 70 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs 62 to 83. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 64 to 85. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 63 to 71 near the shore to 56 to 63 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 70 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs 62 to 83. East winds 10 to 25 mph with gusts to 45 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 87 near the shore to around 70 near 5000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Gusts up to 45 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 74 near the shore to around 52 near 5000 feet. Northeast winds 10 to 15 mph decreasing to up to 15 mph after midnight. Gusts up to 45 mph. Chance of rain 20 percent.

Saturday: Breezy. 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 25 mph with gusts to 45 mph. Chance of rain 20 percent.

Puna

Today: Breezy. Partly sunny with scattered showers. Highs 79 to 84 near the shore to around 70 at 4000 feet. Northeast winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Numerous showers in the evening, then occasional showers after midnight. Lows 63 to 71 near the shore to around 56 at 4000 feet. North winds up to 15 mph. Chance of rain 80 percent.

Saturday: Mostly cloudy. Occasional showers in the morning, then numerous showers in the afternoon. Highs 77 to 84 near the shore to around 67 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 90 percent.

Waikoloa

Today: Sunny and breezy. Isolated showers in the afternoon. Highs 83 to 90 near the shore to 66 to 76 above 4000 feet. Northeast winds up to 25 mph with gusts to 45 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Isolated showers after midnight. Lows around 74 near the shore to 51 to 56 above 4000 feet. Southeast winds up to 25 mph with gusts to 45 mph. Chance of rain 20 percent.

Saturday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs 81 to 88 near the shore to 65 to 73 above 4000 feet. Northeast winds up to 25 mph with gusts to 45 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

High pressure far north of the islands will maintain breezy and gusty trade winds through early next week. Passing showers will favor will favor windward slopes, especially during nights and mornings, with some light rainfall occasionally spreading leeward.

Discussion

A stable, breezy, and gusty trade wind flow remains in place, driven by strong high pressure sitting roughly 800 to 900 miles north of the state, and a robust mid-level ridge over the region is maintaining stable conditions with an inversion based between 5,000 and 7,000 feet. A narrow band of low-level moisture that moved through in the evening has largely cleared out, but another band of shallow moisture will move onto windward slopes this morning.
A modest uptick in winds is due today as the high to the north builds slightly. This will lead to borderline Wind Advisory conditions the typically windy areas, such as the Maui Central Valley, portions of west Maui, the leeward areas of the Kohala Districts, the Humuula Saddle, Kau, and parts of the Hawaii Volcanoes National Park. The shallow moisture moving in will produce modest rainfall, with less than a quarter of an inch falling over most windward slopes today. With the exception of afternoon showers over the Kona slopes of the Big Island, leeward areas will experience little accumulation.
Breezy trade winds and a typical summertime rainfall pattern will prevail this weekend into early next week. Modest showers will be focused over windward areas, mainly at night and in the morning. With the exception of afternoon and evening showers over the Kona slopes of the Big Island, leeward areas will be mostly dry. Trades look to decline to moderate levels Tuesday or Wednesday as the high to the north is weakened and displaced eastward.

Aviation

Breezy to locally windy trade winds will continue across the Hawaii region for the next few days. Brief passing showers are expected mainly over windward and mountain areas, favoring the overnight to early morning hours.
AIRMET Sierra for mountain obscuration remains in effect for windward mountain slopes of Kauai, Oahu, Molokai, Maui, and Big Island. This AIRMET will likely diminish in coverage later this morning.
AIRMET Tango remains in effect for moderate low level turbulence over and downwind of island mountains due to the breezy trade winds.

Marine

Strong easterly trades will continue into early next week, supporting the Small Craft Advisory in place for all waters. Seas have responded and will remain rough, with heights hovering around and just under the advisory level over exposed waters. Guidance shows a slight downward trend next week between Tuesday and midweek due to the surface ridge potentially weakening to the north.
Surf along east-facing shores will remain rough through early next week due to the aforementioned strong trades locally and upstream of the state.
Surf along south-facing shores will trend up to around average this weekend as a small south swell arrives. This should be short- lived, with a downward trend expected early next week. Despite a blocking high that has set up over our typical swell window near/southeast of New Zealand, guidance shows a gale forming to its northeast with the head of the fetch aimed at the islands around 2,500-2,700 nautical miles away within the 170 to 190-degree directional band. Given the shorter travel distance, surf could trend up late next week if this system materializes this weekend.
Surf along north-facing shores could trend up above flat levels early next week due to a small, medium-period northwest swell from a marginal gale lifting northeastward toward the Aleutians today. On its heels is a compact storm-force low developing near Japan that could send a similar northwest swell through the area late next week.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Sunday for all Hawaiian waters.

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Data Courtesy of NOAA.gov