Hilo

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 86 near the shore to 70 to 75 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with isolated showers early in the evening, then partly cloudy with scattered showers in the late evening and overnight. Lows 66 to 71 near the shore to around 55 at 4000 feet. Light winds. Chance of rain 50 percent.

Friday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 86 near the shore to 70 to 75 at 4000 feet. East winds up to 10 mph. Chance of rain 50 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 early in the evening, then partly cloudy with isolated showers in the late evening and overnight. Lows 70 to 76 near the shore to around 56 near 5000 feet. Light winds. Chance of rain 50 percent.

Friday: Mostly sunny with isolated showers 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.

Waimea

Today: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to 70 to 81 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Scattered showers early in the evening. Lows around 69 near the shore to 57 to 63 near 3000 feet. Light winds. Chance of rain 50 percent.

Friday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to 70 to 81 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Kohala

Today: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to 70 to 81 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Scattered showers early in the evening. Lows around 69 near the shore to 57 to 63 near 3000 feet. Light winds. Chance of rain 50 percent.

Friday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to 70 to 81 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

South Big Island

Today: Sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 87 near the shore to around 74 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers early in the evening, then partly cloudy with isolated showers in the late evening and overnight. Lows around 71 near the shore to around 54 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Friday: Breezy. Sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 87 near the shore to around 74 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Puna

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 86 near the shore to 70 to 75 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with isolated showers early in the evening, then partly cloudy with scattered showers in the late evening and overnight. Lows 66 to 71 near the shore to around 55 at 4000 feet. Light winds. Chance of rain 50 percent.

Friday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 86 near the shore to 70 to 75 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Today: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 87 near the shore to 71 to 77 above 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers early in the evening, then partly cloudy with isolated showers in the late evening and overnight. Lows around 73 near the shore to 52 to 59 above 4000 feet. Northwest winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Friday: Sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 87 near the shore to 71 to 77 above 4000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A lighter trade wind pattern will then prevail tonight through Saturday, with localized land and sea breezes in leeward areas. Showers will favor windward slopes and coasts at night and the island interior and leeward areas each afternoon. A few of the showers could produce localized downpours during the afternoon and early evening hours Thursday and Friday. A band of enhanced moisture may increase shower coverage statewide late Saturday through and Sunday as the trades begin to restrengthen. A more typical trade wind weather pattern should return Monday through the middle of next week, with moderate trades prevailing.

Discussion

Currently at the surface, a weak east-west oriented ridge of high pressure is located around 250 miles north of Honolulu, while a weakening cold front is positioned around 525 miles north of Kauai. The resulting gradient is producing light to locally moderate trade winds, with land breezes present in many leeward areas. Infrared satellite imagery shows mostly clear to partly cloudy conditions across most of the state, with a bit more cloud cover over windward sections of Maui and the Big Island. Radar imagery shows scattered showers moving windward Big Island and east Maui, with nothing more than isolated shower coverage over windward sections of the other isles, and dry conditions over leeward areas statewide. Main short term concern revolves around rain chances during the next few days.
The ridge north of the islands will weaken during the next couple days as the cold front pushes southward and closer to the state, before stalling out around 250 miles north of Kauai by late Friday afternoon. The front will then weaken into a trough north of the area Friday night, then retrograde northwestward over the weekend. High pressure will build to the distant north over the weekend as well, then settle southeastward to a position well to the northeast of the islands early next week. A light to moderate hybrid trade wind pattern is expected to prevail through Saturday, with land and sea breezes developing in many of the more sheltered leeward areas. Model guidance suggests that the trades should be on the rebound Saturday night and Sunday, with moderate trades then holding in place Sunday through the middle of next week.
As for the remaining weather details, the pattern will change very little through Saturday, with showers favoring windward slopes and coasts at night into the early morning hours, then transitioning over to the island interior and leeward areas each afternoon. A few of the showers could produce brief localized downpours Thursday and Friday afternoons, with drier more stable conditions expected on Saturday. A band of enhanced moisture appears to accompany the returning trades late Saturday night and Sunday, bringing an increase in shower coverage statewide as it moves through the islands from east to west. Some lingering showery conditions could hold in place Sunday night, before we transition back to a more typical trade wind weather pattern Monday through the middle of next week.

Aviation

Lighter trade winds today will increase coverage of afternoon sea breezes over the islands. Clouds will build over mountain and island interior sections during the day with periods of afternoon to evening showers. Land breezes will develop in the evening hours clearing out most of the island cloud cover. Brief periods of MVFR conditions are possible in the afternoon to early evening hours as low clouds and showers form over each island.
No AIRMETs in effect. AIRMET Sierra for mountain obscuration may develop over island interior sections from the afternoon to evening hours as cloud ceilings expand in coverage.

Marine

A surface ridge far north of the state will weaken and drift south over the next couple of days. This will produce light to moderate trade winds through Friday night. The background flow may shift out of the east-southeast and modestly strengthen this weekend. By Monday, high pressure will build to the north. This will induce moderate easterly flow across the area.
The current small south swell will persist through today. A series of small, long-period south swells can be expected through the weekend and into early next week. Also, a small, short-period southeast swell will hang on through the weekend. Small, short- period north and northwest swells will linger through Friday, with a slightly larger short-period north swell expected over the weekend. A small, longer-period northwest swell may arrive early next week. Due to lighter trade winds over and upwind of the state, short-period choppy surf will remain rather small along east-facing shores throughout the forecast period.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov