Photo Credit: James Grenz

Hilo

Today: Partly sunny with scattered showers. Highs around 81 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 showers likely. Lows around 66 near the shore to around 52 at 4000 feet. East winds up to 10 mph shifting to the northwest after midnight. Chance of rain 70 percent.

Tuesday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 64 to 69 at 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Kona

Today: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 80 to 85 near the shore to around 71 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 66 to 72 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 40 percent.

Tuesday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 79 to 84 near the shore to around 70 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.

Waimea

Today: Partly sunny with scattered showers. Highs around 80 near the shore to 71 to 78 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 65 near the shore to 51 to 59 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tuesday: Breezy. Partly sunny with scattered showers. Highs around 79 near the shore to 70 to 77 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Kohala

Today: Partly sunny with scattered showers. Highs around 80 near the shore to 71 to 78 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 65 near the shore to 51 to 59 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tuesday: Breezy. Partly sunny with scattered showers. Highs around 79 near the shore to 70 to 77 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs around 83 near the shore to around 72 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 68 near the shore to around 52 near 5000 feet. East winds up to 20 mph shifting to the northeast 10 to 20 mph after midnight. Chance of rain 20 percent.

Tuesday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 82 near the shore to around 71 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: Partly sunny with scattered showers. Highs around 81 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 showers likely. Lows around 66 near the shore to around 52 at 4000 feet. East winds up to 10 mph shifting to the northwest after midnight. Chance of rain 70 percent.

Tuesday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 64 to 69 at 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Waikoloa

Today: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 82 near the shore to 66 to 73 above 4000 feet. Northeast winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy. Isolated showers in the evening. Lows around 70 near the shore to 48 to 56 above 4000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 81 near the shore to 65 to 72 above 4000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light to moderate trade winds will prevail today, edge upward tonight, then become locally breezy from late Tuesday afternoon into the upcoming weekend. Showers will favor windward and mauka sections of Maui County and the Big Island today, with windward Oahu and Kauai seeing an increase in showers tonight and Tuesday. Dry and stable conditions are then expected Tuesday night through next weekend, with limited trade wind showers favoring windward and mauka areas, particularly during nights and mornings.

Discussion

Currently at the surface, a trough of low pressure is located around a hundred miles northeast of Maui, with another trough a few hundred miles southeast of the Big Island. Meanwhile, a ridge axis is positioned around 200 miles north of Kauai. The resulting gradient is producing light to moderate north-northeasterly winds across the western islands and light to moderate east- northeasterly trades over the eastern end of the state. Infrared satellite imagery shows partly to mostly cloudy conditions over windward areas, with clear to partly cloudy skies in leeward locales. Radar imagery shows scattered showers affecting windward areas of Maui County and the Big Island, isolated showers over windward Oahu, and with very little if any shower activity on Kauai. Main short term focus revolves around rain chances and trade wind trends during the next couple days.
The surface trough northeast of the islands will weaken and gradually dissipate as it shifts slowly westward today through Tuesday. Light to moderate trades with local sea breezes can be expected today. The trades will edge upward slightly tonight, then become locally breezy Tuesday afternoon. Surface ridging north of the islands will then remain the dominant weather feature through Saturday, with moderate to locally breezy trades prevailing. A front approaching from the northwest may weaken the trades for the tail end of the upcoming weekend.
As for the remaining weather details, a band of clouds and showers on the southwest periphery of the surface trough will move very slowly westward during the next couple days. The shower focus will remain over mainly windward sections of Maui County and the Big Island today, with fewer showers expected over Oahu and even less over Kauai. As the trough dampens out tonight and Tuesday, we should see showers disperse more uniformly across the state, with windward and mauka areas remaining the main targets. A drier and more stable airmass will then build over the islands Tuesday night through the upcoming weekend, with limited trade wind showers favoring windward and mauka areas, particularly during nights and mornings.

Aviation

A weak surface trough lingering in the area will support the light to moderate north-northeast winds continuing over Kauai and Oahu, with east to southeast trades holding over the eastern end of the state today. A return of moderate to breezy easterly trades is expected by tonight as the trough diminishes and high pressure builds to the north. Although VFR conditions will prevail through the 24-hr TAF period, late night/early morning clouds and showers focusing over some windward locations could translate to brief periods with MVFR CIGS/VSBYS.
No AIRMETs are currently in effect.

Marine

A weak low level trough persists over the local waters, causing northeast winds over the western part of the state and east winds from Molokai eastward. More typical trade winds will become reestablished by Tuesday and will strengthen through Wednesday as high pressure builds in to our north. Winds will likely reach Small Craft Advisory levels over the typically windy waters around Maui County and the Big Island Tuesday through Thursday. A slight decrease in trade wind speeds are expected Friday with the high becoming centered far northeast of the area by then.
The current northwest swell will continue to lower through the day. A smaller northwest swell is on tap during the Tuesday through Wednesday time period. A much larger, and rather long period, northwest swell is expected to fill in Thursday, then peak Thursday night and early Friday before lowering gradually over the weekend. This swell will easily exceed advisory levels, and will likely reach low-end warning levels, during the peak of the swell. Small, mainly background south swells are expected through this weekend and on through most of next week. Short period choppy surf will remain small along east facing shores over the next couple of days, then pick up beginning around Wednesday and remain elevated into next weekend as trade winds strengthen over and upwind of the state.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov