Hilo

Today: Partly sunny. Scattered showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs 77 to 83 near the shore to 65 to 70 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 68 near the shore to around 54 at 4000 feet. South winds up to 10 mph. Chance of rain 50 percent.

Thursday: Partly sunny with scattered showers. Highs 78 to 83 near the shore to 65 to 70 at 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny in the morning, then partly sunny with scattered showers and slight chance of thunderstorms in the afternoon. Highs 81 to 87 near the shore to around 67 near 5000 feet. Light winds. Chance of rain 50 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows 67 to 72 near the shore to 45 to 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Thursday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 81 to 86 near the shore to around 67 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Partly sunny. Scattered showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs 64 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 62 near the shore to 51 to 60 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Thursday: Breezy. Partly sunny with scattered showers. Highs 64 to 85. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Today: Partly sunny. Scattered showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs 64 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 62 near the shore to 51 to 60 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Thursday: Breezy. Partly sunny with scattered showers. Highs 64 to 85. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny in the morning, then partly sunny with scattered showers and slight chance of thunderstorms in the afternoon. Highs around 82 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows around 70 near the shore to around 49 near 5000 feet. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Thursday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 82 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny. Scattered showers in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Highs 77 to 83 near the shore to 65 to 70 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 68 near the shore to around 54 at 4000 feet. South winds up to 10 mph. Chance of rain 50 percent.

Thursday: Partly sunny with scattered showers. Highs 78 to 83 near the shore to 65 to 70 at 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers and slight chance of thunderstorms in the afternoon. Highs 80 to 86 near the shore to 65 to 71 above 4000 feet. East winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 40 percent.

Tonight: Mostly clear with isolated showers. Lows 64 to 72 near the shore to 45 to 53 above 4000 feet. North winds up to 10 mph shifting to the southeast after midnight. Chance of rain 20 percent.

Thursday: Sunny in the morning then becoming partly sunny. Isolated showers. Highs 80 to 86 near the shore to 66 to 71 above 4000 feet. North winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Trade winds will spread across the islands through today as high pressure persists to our north. An upper trough will help enhance showers, and could trigger a thunderstorm or two on the Big Island during the afternoon hours. A more stable trade wind pattern is expected for the second half of the week.

Discussion

. A ridge is strengthening to our north as a front weakens to the northeast. An upper trough remains near the islands, with associated thunderstorms persisting east through southeast of the Big Island. The ridge will allow trade flow to fill in across the island chain through today, and then persist through the end of the week. The upper trough will continue to provide some instability, which may enhance rainfall totals. Most of the instability remains to the east of the islands, corroborated by the presence of thunderstorms to the east and southeast of the Big Island. However, enhanced rainfall may occur across portions of Maui and the Big Island through this evening. Overnight soundings show an unstable airmass with no capping inversion. Temperatures aloft remain just cold enough for possible thunderstorm development across the Big Island this afternoon during heating maximum as well as continued thunderstorm development across coastal waters northeast through southeast of the Big Island this morning.
Models show that upper ridging will push in from the west as the upper trough moves away on Thursday. This will help stabilize our airmass, reducing rainfall totals. High pressure at the surface will drive a return to a more typical trade wind pattern of mainly windward clouds and showers for the second half of the week.

Aviation

High pressure building in over the region will produce fair weather conditions in a light to moderate trade wind weather pattern through Thursday. An upper level trough lingers near the Big Island this morning with some showers and thunderstorms currently drifting east into the coastal waters near east Maui and north of the Big Island.
Light trade winds will allow sea breeze winds to develop today along southwest and west terrain sheltered slopes of each island. Convergence between these wind patterns will lead to more variability in the wind direction and the potential for brief afternoon showers over leeward areas. Otherwise expect a drier weather pattern with brief passing showers favoring windward and mountain areas through the morning hours.
No AIRMETs are currently in effect, however a period of moderate clear air turbulence may develop over the state later today.

Marine

The pressure gradient south of a surface high pressure system centered more than 770 nm north-northeast of Honolulu is currently producing light to moderate trade winds across most of the area. This surface high will move slowly east during the next couple of days. The forecast guidance continues to indicate the trade winds may strengthen slightly later this week as a surface ridge builds north of the area. Therefore, Small Craft Advisory (SCA) conditions may develop starting Friday or Friday night over the typically windier waters adjacent to the islands of Maui County and the Big Island. The SCA conditions may persist over these windier waters into this weekend.
The nearshore buoys indicate the current northwest swell has lowered overnight, and it is now close to the wave model guidance. This swell will continue to slowly lower through early Thursday morning. Another northwest swell is expected to arrive late Thursday, and peak on Friday. Surf associated with this swell may briefly approach the High Surf Advisory (HSA) thresholds along some north and west facing shores of the smaller islands on Friday. This northwest swell is expected to gradually lower from Friday night through Saturday night. A third northwest swell is forecast to arrive on Sunday, and peak from Sunday night into early Monday. Surf produced by this swell may reach the HSA criteria along most north and west facing shores of the smaller islands based on the latest wave model guidance. This swell is expected to slowly lower from late Monday through next Tuesday.
Small background south swell energy is expected through tonight. A small long-period south swell is expected to boost surf heights slightly along south facing shores from Thursday into Friday. The wave model guidance indicates that surf along south facing shores will return to more typical small background conditions from this weekend into early next week. Expect modest short-period, choppy surf along east facing shores into this weekend due to the trade wind speeds remaining in the light to moderate range over and upwind of the state.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov