Hilo

Today: Cloudy with occasional showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 83 near the shore to 68 to 73 at 4000 feet. East winds up to 15 mph. Chance of rain 90 percent.

Tonight: Cloudy. Showers likely in the evening, then occasional showers after midnight. Lows around 68 near the shore to around 54 at 4000 feet. Southeast winds up to 10 mph shifting to the west after midnight. Chance of rain 90 percent.

Saturday: Cloudy with occasional showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 83 near the shore to 68 to 73 at 4000 feet. East winds up to 10 mph. Chance of rain 90 percent.

Kona

Today: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 81 to 86 near the shore to around 68 near 5000 feet. Light winds. Chance of rain 40 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 69 to 74 near the shore to around 55 near 5000 feet. Light winds. Chance of rain 20 percent.

Saturday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 81 to 86 near the shore to around 68 near 5000 feet. Northeast winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 40 percent.

Waimea

Today: Breezy. Partly sunny with scattered showers. Highs around 81 near the shore to 68 to 78 near 3000 feet. East winds up to 20 mph. Chance of rain 50 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 20 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs around 81 near the shore to 68 to 78 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Kohala

Today: Breezy. Partly sunny with scattered showers. Highs around 81 near the shore to 68 to 78 near 3000 feet. East winds up to 20 mph. Chance of rain 50 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 20 mph. Chance of rain 50 percent.

Saturday: Breezy. Partly sunny with scattered showers. Highs around 81 near the shore to 68 to 78 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 85 near the shore to around 72 near 5000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 70 near the shore to around 53 near 5000 feet. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Saturday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 85 near the shore to around 72 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Puna

Today: Cloudy with occasional showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 83 near the shore to 68 to 73 at 4000 feet. East winds up to 15 mph. Chance of rain 90 percent.

Tonight: Cloudy. Showers likely in the evening, then occasional showers after midnight. Lows around 68 near the shore to around 54 at 4000 feet. Southeast winds up to 10 mph shifting to the west after midnight. Chance of rain 90 percent.

Saturday: Cloudy with occasional showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 83 near the shore to 68 to 73 at 4000 feet. East winds up to 10 mph. Chance of rain 90 percent.

Waikoloa

Today: Sunny in the morning then becoming partly sunny. Breezy. Highs around 85 near the shore to 69 to 75 above 4000 feet. East winds up to 20 mph shifting to the north up to 10 mph in the afternoon.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 72 near the shore to 51 to 58 above 4000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Saturday: Sunny in the morning then becoming partly sunny. Highs around 85 near the shore to 69 to 75 above 4000 feet. East winds up to 15 mph shifting to the north in the afternoon. Gusts up to 35 mph.

Detailed Forecast

Synopsis

Moderate and breezy trade winds will continue, with clouds and showers favoring windward and mauka locations as areas of moisture move through. Expect some showers to carry over into our leeward areas periodically through the weekend due to an upper disturbance in the area. A drier trade wind pattern is expected next week as the upper disturbance lifts away to the north.

Discussion

A showery trade wind pattern is anticipated through the holiday weekend due to a weak mid- to upper-level trough moving through the area. The overnight soundings at Hilo and Lihue showed weaker/elevated trade wind inversions with a sufficient amount of low-level moisture (PWs around 1.18-1.34 inches) in place. This environment combined with the breezy trades and areas of moisture moving through will support decent windward shower coverage, with some holding together into leeward areas of the smaller islands. Although confidence is low, trades could ease slightly this evening into the weekend for the western end of the state due to a combo of the upper trough in the area and the ridge weakening to the north.
For next week, guidance depicts the aforementioned upper trough lifting northward and away from the state. This will translate to a more stable trade wind pattern with less windward shower coverage each day.

Aviation

Moderate to locally breezy trade winds will continue to push patches of stable and showery low clouds over the islands from the E, leading to periods of MVFR VIS/CIG, mainly over windward areas. A nearby low aloft will continue to slightly destabilize the island atmosphere, with radar detecting a few heavy rain cores, with some cloud tops extending as high as 12 kft. Shower coverage will be sufficiently great at time to warrant AIRMET Sierra for windward slopes of most islands at times through tonight.

Marine

The pressure gradient back across the islands from surface high pressure centered far north to northeast of the state will maintain fresh to locally strong trade winds over both the local nearshore and offshore waters the next several days. The Small Craft Advisory remains in effect for the winder areas surrounding Maui County and Big Island through Saturday afternoon but will likely need to be extended even further in time.
The offshore northwest buoys are picking up on longer period energy from the next west northwest swell that will be arriving and slowly building over the more western islands through Saturday. This small, medium period swell will peak surf along the north and west facing shores of Kauai later this afternoon and Oahu on Saturday. A slightly larger reinforcing west northwest swell will fill in late Saturday into early Sunday. This swell will likely push higher sets to around head high along various north and west facing shores Sunday afternoon and evening. South facing shore surf will remain low today with only a small background southerly swell. The weekend arrival of a slightly higher, longer period southwest south swell will provide a slight boost to surf along southern exposures from this weekend through the middle of next week. Moderate to fresh trades will continue to generate rough, choppy surf along eastern facing shores. East shores that have some southern exposure may experience slightly higher waves from south swell wrap.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov