Hello

Today: Rather cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 82 near shore at around 70 to 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

This evening: Rather cloudy. Light showers in the evening, then showers likely after midnight. Lows 64 to 70 near shore at about 54 to 4000 feet. Northeast winds up to 10 mph shifting to the northwest after midnight. Chance of rain 70 percent.

Friday: Partially sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs around 83 near shore at around 71 at 4000 feet. Northeast winds around 10 mph. Chance of rain 70 percent.

Kona

Today: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs of 80 to 85 near shore to about 68 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

This evening: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 69 to 74 near shore to about 53 near 5000 feet. Light winds. Chance of rain 30 percent.

Friday: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs of 81 to 86 near shore to about 69 near 5000 feet. Light winds. Chance of rain 50 percent.

Waimea

Today: Costs. Partly sunny with scattered showers. Highs around 81 near shore to 67 to 77 near 3000 feet. East winds 10 to 20 mph diminishing to 15 mph in the afternoon. Chance of rain 50 percent.

This evening: Mostly cloudy with scattered showers. Lows around 67 near shore to 52 to 62 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs around 81 near shore to 68 to 78 near 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

Kohala

Today: Costs. Partly sunny with scattered showers. Highs around 81 near shore to 67 to 77 near 3000 feet. East winds 10 to 20 mph diminishing to 15 mph in the afternoon. Chance of rain 50 percent.

This evening: Mostly cloudy with scattered showers. Lows around 67 near shore to 52 to 62 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Highs around 81 near shore to 68 to 78 near 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

big south island

Today: Costs. Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 84 near shore to around 72 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

This evening: Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Lows around 70 near shore to around 51 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 85 near shore to around 72 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

puna

Today: Rather cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 82 near shore at around 70 to 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

This evening: Rather cloudy. Light showers in the evening, then showers likely after midnight. Lows 64 to 70 near shore at about 54 to 4000 feet. Northeast winds up to 10 mph shifting to the northwest after midnight. Chance of rain 70 percent.

Friday: Partially sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs around 83 near shore at around 71 at 4000 feet. Northeast winds around 10 mph. Chance of rain 70 percent.

Waikoloa

Today: Quite sunny. Isolated showers in the afternoon. Highs around 85 near shore to 68 to 74 above 4000 feet. Northwest winds up to 15 mph. Chance of rain 20 percent.

This evening: Generally clear. Isolated showers in the evening. Lows around 72 near shore to 49 to 58 above 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Friday: Quite sunny. Scattered showers in the afternoon. Highs around 85 near shore to 69 to 75 above 4000 feet. Light winds. Chance of rain 50 percent.

Synopsis

Trade winds will gradually ease from later in the day and Friday through this weekend. A rather typical trade wind weather pattern will concentrate precipitation over the windward and mauka areas, while clouds and showers will likely develop over the upwind sections of the big leeward island each afternoon and evening. . The trade winds should strengthen again from the beginning of next week.

Discussion

A 1028 mb surface high, centered near 41N 137W, weakened as it moved slowly northeast. A surface ridge extends west-southwest of this feature to a point about 730 miles north of Lihue. The pressure gradient begins to relax to the south and southwest of these features, so trade wind speeds are moderate in most areas. Loops of water vapor satellite imagery indicate that a mid-level ridge is above the state, so the atmosphere remains relatively stable. Satellite imagery and radar reflectivity data show scattered to broken low clouds with scattered showers moving into the windward sides of most islands early this morning. Some low cloud and light showers are also carried to the lee sections of some of the smaller islands.
Forecasts indicate that the surface high will continue to move northeast and weaken over the next two days. At the same time, a weak front will weaken the western end of the surface ridge which currently lies far north of the islands. This will cause the pressure gradient on the state to relax further from later today and tonight through Friday. Therefore, expect the trade winds to ease slightly throughout this weekend.
The mid-level ridge will likely continue to maintain stable atmospheric conditions throughout the region. Therefore, expect low cloud and commercial showers to persist mostly over windward and mauka sections. Additionally, there will be clouds and showers every afternoon and evening over the upstream sections of the Big Leeward Island. Mid and upper level lows are expected to establish over the islands this weekend. As a result, pockets of increased humidity could increase precipitation this weekend, primarily for the Big Island and Maui County. There may also be a slight increase in afternoon clouds and showers over sheltered leeward areas of some islands.
Building surface high pressures far to the north of the state early next week could cause locally gusty trade winds to return by Monday. The upper level low pressure area is expected to move west of the area allowing an upper level ridge to re-establish over the area. This will likely lead to a relatively dry and stable trade wind weather pattern with typical modest exchange showers concentrated over the windward and mauka areas.

Aviation

Trade winds will decrease today and tomorrow to a light to moderate range as the high pressure ridge north of the islands weakens. Light to moderate trade winds will continue throughout the weekend with passing showers over windward and mountainous areas, favoring overnight into the early hours of the morning. Most VFR conditions are expected with brief periods of MVFR ceilings over the north to east sections of each island.
No AIRMET currently in effect. Showers developing over windward areas of each island could produce low ceilings this morning and later tonight. AIRMET Sierra broadcast for mountain obscurations may be required during these nighttime periods.

Marine

High pressure in the far north of the state will support moderate to cool trade winds throughout the day. With the winds easing slightly, the small craft advisory that was in effect for generally windy areas around Maui County and the Big Island has been rescinded. The top is expected to gradually weaken throughout the weekend, leading to further easing in trading. Trading will strengthen again to cool to strong levels early next week as a new high builds north of the islands.
The south shore surf will gradually decrease through Saturday as the current southerly swell moves. However, a series of new long period southern swells will increase the south shore surf above the summer average from Sunday through the middle of next week.
Minimal surf on the north coast will continue into next week.
Steady trade wind swells will remain below normal, choppy waves on the east coast until next week. A small swell from the northeast will also cross the islands from late Friday to early next week, giving a little boost to the north and east facing coasts.

Watchdogs/Warnings/HFO Advisories

None.

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Data reproduced with kind permission from NOAA.gov