Photo Credit: James Grenz

Hilo

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 78 to 84 near the shore to 65 to 70 at 4000 feet. Northeast winds up to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 70 near the shore to around 56 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Thursday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 77 to 83 near the shore to around 69 at 4000 feet. Northwest winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 70 percent.

Kona

Today: Mostly cloudy. Scattered showers in the afternoon. Highs 82 to 88 near the shore to 66 to 71 near 5000 feet. Light winds. Chance of rain 50 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 49 to 54 near 5000 feet. Light winds. Chance of rain 40 percent.

Thursday: Partly sunny. Scattered showers in the afternoon. Highs around 86 near the shore to around 68 near 5000 feet. South winds up to 10 mph shifting to the west in the afternoon. Chance of rain 40 percent.

Waimea

Today: Breezy. Partly sunny with scattered showers. Highs 64 to 83. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Scattered showers. Lows 62 to 70 near the shore to 54 to 61 near 3000 feet. East winds 10 to 20 mph decreasing to up to 20 mph after midnight. Chance of rain 50 percent.

Thursday: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 63 to 83. 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 64 to 83. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Scattered showers. Lows 62 to 70 near the shore to 54 to 61 near 3000 feet. East winds 10 to 20 mph decreasing to up to 20 mph after midnight. Chance of rain 50 percent.

Thursday: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 63 to 83. 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 cloudy. Isolated showers in the afternoon. Highs around 84 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows around 73 near the shore to around 52 near 5000 feet. Northeast winds up to 15 mph.

Thursday: Breezy. Mostly 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. Northeast winds up to 25 mph shifting to the east 10 to 25 mph in the afternoon. Chance of rain 20 percent.

Puna

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 78 to 84 near the shore to 65 to 70 at 4000 feet. Northeast winds up to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 70 near the shore to around 56 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Thursday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 77 to 83 near the shore to around 69 at 4000 feet. Northwest winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 70 percent.

Waikoloa

Today: Breezy. Mostly sunny with isolated showers. Highs 82 to 88 near the shore to 66 to 73 above 4000 feet. Northeast winds up to 25 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows around 73 near the shore to 51 to 56 above 4000 feet. East winds up to 25 mph.

Thursday: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 82 to 87 near the shore to 66 to 73 above 4000 feet. Southeast winds up to 25 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Broad high pressure north of the state will drive moderate to breezy trade winds for the next few days with a slight decrease expected by the weekend. Stable conditions will focus showers over windward areas, and leeward areas will be rather dry, though leeward Big Island will experience clouds and showers each afternoon and evening.

Discussion

High pressure remains situated to the north of Hawaii driving stable trade wind weather expected over the next week. Current infrared satellite and radar show scattered showers tracking over the islands from the trade wind flow. 12Z soundings show a weaker and more elevated inversion than previous ones with inversion height between 6 to 7 kft. Precipitable water values skipped a bit higher to around 1.5 to 1.6 inches. Persistent mid-level ridging will maintain stability, so rainfall totals will not be significant. Thus, expect a more typical pattern of windward rainfall to persist through midday, and possibly filling in again tonight into Thursday. Leeward areas should stay mostly dry, but upper leeward slopes will see occasional passing showers. Leeward Big Island will continue to see typical afternoon cloud build ups and showers, then clearing at night, into next week.
A slight decrease in trade winds is expected heading into the weekend. The ridge to the north will be pushed southward on Friday and Saturday, then meander about 400 to 600 miles north of Kauai into early next week. With the ridge a little closer to the islands, we should experience a slight decrease in the trades. A typical distribution of trade wind showers over mainly windward slopes will prevail. A typical summertime upper low will move over the islands over the weekend and may provide a little bit of enhancement to the incoming clouds and showers.

Aviation

Moderate to breezy ENE trade winds will deliver clumps of showery low clouds that will primarily focus over windward coasts and slopes, producing periods of relatively short-lived MVFR VIS/CIG in SHRA. Otherwise, VFR conditions will prevail.

Marine

Fresh to strong easterly trades will continue through the weekend, as the surface ridge remains north of the area. This supports the Small Craft Advisory continuing for the windier channels and waters around Maui County and the Big Island each day.
Surf along south facing shores will slowly ease through Thursday as the current south-southwest swell fades. Expect a mix of this the fading south-southwest swell and a small, medium-period southeast swell through Thursday. A fresh, long-period south swell is expected to arrive Thursday night into Friday, then peak late Friday into Saturday. This swell will hold through early next week as it slowly fades.
Surf along north-facing shores will remain up above the summertime average (flat) through a good portion of the week as small, short-period north to north-northwest swells move through.
Surf along east-facing shores will remain small and choppy over the next several days due to limited trade wind fetch upstream of the islands.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov