Hilo

Today: Cloudy. Scattered showers early in the morning, then scattered showers and isolated thunderstorms in the late morning and afternoon. Highs around 85 near the shore to 70 to 75 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 70 near the shore to around 56 at 4000 feet. Light winds. Chance of rain 50 percent.

Wednesday: Mostly cloudy with scattered showers. Highs around 85 near the shore to 70 to 75 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny early in the morning then becoming mostly cloudy. Isolated showers early in the morning, then scattered showers and isolated thunderstorms in the late morning and afternoon. Highs 83 to 88 near the shore to around 70 near 5000 feet. Light winds. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows 71 to 76 near the shore to around 57 near 5000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Mostly sunny early in the morning then becoming mostly cloudy. Isolated showers early in the morning, then scattered showers in the late morning and afternoon. Highs 83 to 88 near the shore to around 70 near 5000 feet. Light winds. Chance of rain 50 percent.

Waimea

Today: Mostly cloudy. Scattered showers early in the morning, then scattered showers and isolated thunderstorms in the late morning and afternoon. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 70 near the shore to 58 to 64 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Mostly cloudy with scattered showers. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Kohala

Today: Mostly cloudy. Scattered showers early in the morning, then scattered showers and isolated thunderstorms in the late morning and afternoon. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 70 near the shore to 58 to 64 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Mostly cloudy with scattered showers. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny early in the morning then becoming mostly cloudy. Scattered showers and isolated thunderstorms in the late morning and afternoon. Highs around 87 near the shore to around 74 near 5000 feet. East winds around 10 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with scattered showers. Lows around 72 near the shore to around 55 near 5000 feet. East winds 10 to 15 mph. Chance of rain 30 percent.

Wednesday: Mostly cloudy with scattered showers. Highs around 87 near the shore to around 74 near 5000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Puna

Today: Cloudy. Scattered showers early in the morning, then scattered showers and isolated thunderstorms in the late morning and afternoon. Highs around 85 near the shore to 70 to 75 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 70 near the shore to around 56 at 4000 feet. Light winds. Chance of rain 50 percent.

Wednesday: Mostly cloudy with scattered showers. Highs around 85 near the shore to 70 to 75 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny early in the morning then becoming mostly cloudy. Scattered showers and isolated thunderstorms in the late morning and afternoon. Highs around 87 near the shore to 71 to 77 above 4000 feet. Light winds. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 74 near the shore to 53 to 60 above 4000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Mostly sunny early in the morning then becoming mostly cloudy. Isolated showers early in the morning, then scattered showers in the late morning and afternoon. Highs around 87 near the shore to 71 to 77 above 4000 feet. Light winds. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A weakened high pressure ridge north of the Hawaiian Islands will keep a hybrid wind pattern in place with lighter background trade winds over windward zones and sea breezes over leeward sections of each island during the day. This lighter and more variable wind pattern with island interior clouds each afternoon will last into Wednesday, then the high pressure ridge will begin to build back in north of the region. Trade winds will strengthen from Wednesday night onward into the moderate to locally breezy range from Thursday through early next week. Trade winds trend lighter again by the middle of next week.

Discussion

Local radar imagery this morning shows a well developed band of light to moderate showers drifting through windward Oahu. These showers are associated with a passing low level trough over the Hawaii region. The satellite imagery shows this through over the state with clouds extending from Kauai to just south of the Big Island. Day time sea breezes over the islands may pull in some of this additional moisture and produce a slight increase in clouds and brief showers over island interior sections this afternoon.
A long wave trough far north of the region continues to break down down the subtropical ridge north of the state and decreasing the trade wind flow into Wednesday. As these large scale trade winds weaken, local scale land and sea breezes will strengthen over the islands. This hybrid wind pattern will continue for the next two days with land and sea breezes over leeward areas and light trade winds over the windward zones. Clouds and a few showers will tend to favor afternoons along convergence areas between the trade winds and sea breezes over leeward and island interior sections. Brief showers are also possible in this hybrid wind pattern over windward zones in the overnight to early morning hours. A minor wrinkle to this forecast is a passing low level trough drifting through the island chain today. Deeper moisture moving up the eastern side of this trough may slightly increase clouds and shower trends and interact with sea breezes over island mountain and interior sections. Chances for isolated thunderstorms are forecast over the mountain slopes of the Big Island today as surface heating along the slopes of Mauna Loa and Mauna Kea may trigger deeper convection and isolated thunderstorms in the unstable layer above the trade wind inversion height.
The long wave trough will weaken and drift further northeastward from Wednesday into Thursday, allowing the ridge build back in north of the island chain and strengthen the trade winds across the region. We will transition back to a trade wind pattern on Wednesday evening as the high pressure ridge builds back in. Expect moderate to locally breezy trade winds from Thursday into next week Monday with land and sea breezes fading. Clouds and brief passing showers will trend back towards the windward and mountain sections of each island, favoring the typical overnight to early morning hours.
Another round of weakening trade winds may develop by next week Tuesday as extended forecast guidance shows another long wave trough moving through the North Pacific, breaking down the subtropical ridge north of the islands.

Aviation

Light to moderate trade wind flow will continue to steer ragged bands of clouds and light showers off the Pacific towards mainly northeast facing slopes and coasts. A capping inversion aloft around 07 kft will inhibit most shower activity at lower elevations, but locally heavy showers over interior Big Island and Upcountry Maui may be a concern in the afternoon and early evening. Isolated thunderstorms may develop this afternoon over the Big Island mountain slopes.
Current satellite and radar imagery (as of 2 am HST) reveals multiple bands of clouds passing over and just north of the state but only limited shower activity. VFR flight conditions will likely prevail at most locations today with only brief MVFR ceilings and visibilities in passing showers.

Marine

A weak ridge north of the state will produce gentle to moderate trades today and tomorrow. This pattern will allow for localized overnight land breezes and daytime sea breezes near the coasts. Daytime heating and terrain-induced accelerations can produce pockets of fresh breezes and choppy conditions near some coasts. A return of fresh to strong easterly trades is expected Thursday into the weekend as the ridge restrengthens and drifts north of the area. This may lead to Small Craft Advisory conditions for the windier waters and channels over the eastern end of the state by Thursday.
Surf along south facing shores will remain small from the combination of background south and southeasterly swells through the rest of the week. Recent activity in the South Pacific will lead to a highly anticipated upward trend in surf along south facing shores beginning this weekend and lasting into early next week.
Surf along east facing shores will remain small through the first half of the week as the trades ease. A return of choppy/short- period surf is expected by the end of the week through the weekend as the trades return.
Near flat surf conditions will persist along north facing shores through tomorrow. North facing shores may see a small bump Thursday through the weekend as few small, short period, north and northwest swells move through the area. Surf may continue to trend up early next week as a slightly larger and longer period northwest swell moves over the area.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov