Photo Credit: James Grenz

Hilo

Today: Partly sunny with scattered showers. Highs around 82 near the shore to 66 to 74 at 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Showers likely in the evening, then scattered showers after midnight. Lows 65 to 73 near the shore to around 58 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Showers likely in the morning, then isolated showers in the afternoon. Highs 80 to 85 near the shore to 65 to 74 at 4000 feet. East winds 10 to 15 mph. Chance of rain 60 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 86 near the shore to around 70 near 5000 feet. West winds up to 10 mph. 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 53 to 58 near 5000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Saturday: Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 87 near the shore to around 71 near 5000 feet. North winds up to 10 mph in the morning becoming light. Chance of rain 20 percent.

Waimea

Today: Breezy. Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 70 to 88. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 58 to 65 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Saturday: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 69 to 88. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 70 to 88. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 58 to 65 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Saturday: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 69 to 88. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 87 near the shore to around 70 near 5000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Lows around 74 near the shore to around 54 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Saturday: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs around 87 near the shore to around 70 near 5000 feet. East winds 10 to 20 mph.

Puna

Today: Partly sunny with scattered showers. Highs around 82 near the shore to 66 to 74 at 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Showers likely in the evening, then scattered showers after midnight. Lows 65 to 73 near the shore to around 58 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Showers likely in the morning, then isolated showers in the afternoon. Highs 80 to 85 near the shore to 65 to 74 at 4000 feet. East winds 10 to 15 mph. Chance of rain 60 percent.

Waikoloa

Today: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 82 to 90 near the shore to 68 to 76 above 4000 feet. Northeast winds up to 15 mph shifting to the north in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 74 near the shore to 52 to 58 above 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Saturday: Mostly sunny in the morning then becoming partly sunny. Highs 82 to 90 near the shore to 69 to 76 above 4000 feet. Northeast winds around 10 mph.

Detailed Forecast

Synopsis

Light to moderate trade winds will continue today with some localized sea breezes expected across leeward areas. A return to strong trade winds, and somewhat dry and stable weather, is due this weekend, with trades gradually decreasing during the first half of next week.

Discussion

As expected, little change to the forecast with the morning package. High clouds continue to stream from south to north over the Kauai on the east side of the upper level trough. A surface trough to the east is continuing to disrupt the trades, and will give us another day of lighter winds.
Both the surface and upper level trough will be moving to the west today, allowing the surface ridge north of the islands to once again become the dominant feature. Trade winds are expected to return late today/tonight, building back in from east to west across the state. Some leftover moisture from the surface trough will get caught up in the trades, and could bring an increase of humidity and showers over some windward areas today. With dewpoints approaching and getting in the lower 70s tonight and tomorrow, temperatures may feel warmer than normal, however the returning locally breezy trade winds should help to offset that feeling.
The high pressure rebuilding to the far north of the state this weekend will result in the trades strengthening Saturday into Sunday. Breezy easterly trade winds Saturday are expected to become quite strong and gusty on Sunday as the winds strengthen and veer slightly more towards the northeast. On Sunday, we should see a drier air mass move in across the state and if you combine that with the gusty winds, it could bring some fire weather concerns. Trade winds are expected to gradually decrease Monday through the first half of next week.

Aviation

As a weak, westbound surface trough moves north of the islands, trades will be light to moderate through today, with localized sea breezes during the late morning and afternoon hours. Most areas will remain VFR. Some cloud buildups and showers, with accompanying MVFR conditions, are possible during the afternoon hours. This is especially the case on Kauai as an upper trough moves closer to the isle from the north. And looking ahead, trades will become more robust beginning Saturday.
No AIRMETs are in effect. As the upper level system closes in on Kauai, there is a chance that an AIRMET for mid- to high-level turbulence may be needed.

Marine

A high pressure system remains centered far north of the region as a weak low level trough passes through the northern waters today. This trough passage will keep trade winds in the light to moderate range, before strengthening into the moderate to strong range later tonight through Sunday as the trough passes to the northwest of the state. A Small Craft Advisory (SCA) was issued for the windier eastern waters and channels starting tonight, and this SCA will last into the first half of next week.
A long period south swell will peak today just below High Surf Advisory levels, and then lower gradually over the weekend. The highest surf heights from this swell will break along the south facing shores of the Big Island. A second, but slightly smaller long period south swell is expected to arrive Saturday night and Sunday, peak Sunday night and Monday, then lower gradually Tuesday through Wednesday.
Short period choppy surf will remain rather small along east facing shores into the weekend, with a slight uptick expected early next week as trade winds strengthen. Tropical cyclone activity in the far eastern Pacific may send a small medium period east swell that would likely arrive by the middle of next week. No other significant swells are expected.

HFO Watches/Warnings/Advisories

Small Craft Advisory from 6 PM this evening to 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