Hilo

Today: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 78 to 84 near the shore to around 68 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 60 percent.

Tonight: Mostly cloudy with showers likely. Lows 61 to 70 near the shore to around 55 at 4000 feet. North winds up to 10 mph. Chance of rain 70 percent.

Wednesday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 78 to 84 near the shore to around 69 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 60 percent.

Kona

Today: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 83 to 88 near the shore to around 68 near 5000 feet. Light winds. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy after midnight. Lows around 73 near the shore to around 51 near 5000 feet. Light winds. Chance of rain 50 percent.

Wednesday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 83 to 88 near the shore to around 68 near 5000 feet. Southwest winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 64 to 84. East winds 10 to 20 mph decreasing to up to 20 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 70 near the shore to 54 to 60 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 65 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 64 to 84. East winds 10 to 20 mph decreasing to up to 20 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 70 near the shore to 54 to 60 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 65 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 85 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows around 72 near the shore to around 52 near 5000 feet. Northeast winds up to 15 mph.

Wednesday: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 68 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 78 to 84 near the shore to around 68 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 60 percent.

Tonight: Mostly cloudy with showers likely. Lows 61 to 70 near the shore to around 55 at 4000 feet. North winds up to 10 mph. Chance of rain 70 percent.

Wednesday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 78 to 84 near the shore to around 69 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 60 percent.

Waikoloa

Today: Mostly sunny. Highs 82 to 88 near the shore to 65 to 74 above 4000 feet. Northeast winds up to 15 mph.

Tonight: Partly cloudy. Lows around 73 near the shore to 50 to 55 above 4000 feet. East winds up to 10 mph.

Wednesday: Mostly sunny. Highs 83 to 88 near the shore to 64 to 74 above 4000 feet. East winds 10 to 15 mph shifting to the northwest in the afternoon.

Detailed Forecast

Synopsis

A stable trade wind pattern will persist through the week with breezy to locally windy trades. Periodic light showers will focus over windward and mauka areas during this time. An increase in shower activity is possible over the weekend as an upper-level disturbance approaches the region.

Discussion

A 1029 mb surface high remains approximately 900 miles north- northwest of the islands this morning. Stable conditions continue across the region, with this morning’s soundings showing a sharp trade wind inversion combined with limited low-level moisture and dry air aloft. Radar and satellite imagery continue to show mainly dry conditions across the state, with periodic light showers over the typical windward and mauka areas. Expect these conditions to continue today under breezy to locally windy trades.
High pressure looks to weaken slightly over the next couple of days. This should relax our local pressure gradient a bit, but impulses of moisture embedded in the trade wind flow will keep breezy trades to locally windy trades going through the week. Passing light showers will continue to favor windward and mauka areas with meager rainfall accumulations likely. Aside from some brief afternoon/evening showers over Kona slopes of the Big Island leeward areas will remain mostly dry.
Conditions start to change going into the weekend as guidance continues to show an upper-level disturbance moving across the islands. The increase in instability, combined with bands of moisture embedded in the trade wind flow, will help to enhance shower activity across windward and mauka areas this weekend and into early next week.

Aviation

Breezy trade winds will slowly ramp back up to locally windy conditions tonight. SHRA and brief MVFR conditions should stay confined to windward/mauka locations.
AIRMET Sierra for mtn obsc has been cancelled but may be needed again later today as another band of showery low clouds approaches.
AIRMET Tango remains in effect for mod low-level turb over and downwind of island terrain due to the breezy trade winds.

Marine

Surface high pressure far north of the state will maintain moderate to locally strong easterly trades through today. Trades will gradually weaken to gentle to fresh Thursday into Friday as the high pressure gradually weakens north of the state. A Small Craft Advisory (SCA) for the typical windier waters around Maui County and the Big Island remains in effect through early Wednesday morning where winds will remain strong.
Rough and choppy surf along east-facing shores will persist through today before gradually trending down Wednesday through Thursday.
A small, medium-period, south swell will peak today before gradually trending down tonight and Wednesday. Another small, medium- to long- period south swell will fill in Wednesday night and peak Thursday before gradually easing into the weekend.
A small, medium-period, northwest swell will bring a tiny boost to north shore surf through today. Another small, medium period, northwest swell could fill in late Wednesday and peak Thursday night before gradually trending down into the weekend.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Wednesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov