Hilo

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 79 near the shore to around 65 at 4000 feet. East winds up to 10 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy with numerous showers. Lows around 68 near the shore to around 51 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 60 percent.

Wednesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 79 near the shore to around 65 at 4000 feet. East winds 10 to 15 mph. Chance of rain 60 percent.

Kona

Today: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 83 near the shore to around 68 near 5000 feet. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers. Lows around 72 near the shore to around 51 near 5000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 83 near the shore to around 68 near 5000 feet. Light winds. Chance of rain 40 percent.

Waimea

Today: Partly sunny with scattered showers. Highs around 77 near the shore to 69 to 75 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 67 near the shore to 51 to 58 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs around 77 near the shore to 69 to 75 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Kohala

Today: Partly sunny with scattered showers. Highs around 77 near the shore to 69 to 75 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 67 near the shore to 51 to 58 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs around 77 near the shore to 69 to 75 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 81 near the shore to around 69 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows 65 to 73 near the shore to around 51 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 81 near the shore to around 69 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 79 near the shore to around 65 at 4000 feet. East winds up to 10 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy with numerous showers. Lows around 68 near the shore to around 51 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 60 percent.

Wednesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 79 near the shore to around 65 at 4000 feet. East winds 10 to 15 mph. Chance of rain 60 percent.

Waikoloa

Today: Sunny. Highs around 82 near the shore to 64 to 71 above 4000 feet. North winds up to 10 mph.

Tonight: Mostly clear with isolated showers. Lows around 71 near the shore to 46 to 54 above 4000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Sunny. Isolated showers in the morning. Highs around 82 near the shore to 64 to 71 above 4000 feet. Light winds becoming north up to 10 mph in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A high pressure ridge will linger north of the Hawaiian Islands over the next seven days producing continued moderate to locally breezy trade winds with periods of passing showers favoring the windward and mountain areas of each island with higher precipitation chances in the overnight to early morning hours. Unstable cloud bands from a dissipated cold front will drift into the islands from the north on Saturday and Sunday producing increasing rainfall coverage over all islands.

Discussion

The satellite picture this morning continues to show a stalled frontal system northwest of the islands with a weak upper low northeast of the state. Clouds moving through the easterly trades are unstable enough to produce brief passing showers over windward and mountain areas with more stable conditions moving into the area from late morning to afternoon.
The subtropical ridge remains in place north of Hawaii today with continued moderate to breezy easterly trade winds and brief passing showers. This upper low will keep some overnight to early morning enhancement of shower activity over windward and mountain areas through tonight, then an upper level ridge builds in over the region with more stable conditions and less shower activity from Wednesday through Friday.
The weather pattern trends wetter from Friday night onward as unstable cloud remnants from a dissipated cold front north of the islands is driven south over the state from Saturday into Monday by a high pressure system moving across the Central Pacific basin. One wrinkle in this forecast that could affect precipitation coverage is an unstable upper low developing over the region, helping to increase cloud heights by lifting trade wind inversion heights, just as the low level remnant cloud bands are drifting through the region. If these features line up properly in the long range forecast we may see a brief period of wet weather over the state by next weekend. Stay tuned.

Aviation

With high pressure remaining entrenched far northeast of the area, trade winds will remain moderate to locally breezy through tonight. Showers and any accompanying MVFR conditions in lower ceilings and visibilities will mainly affect windward and mauka locales statewide. VFR will hold sway otherwise.
AIRMETs for mountain obscuration have been posted for the windward sections of most isles. They may be extended through late this morning.

Marine

Moderate to locally strong trades will continue through the weekend, with only minor variations in strength. A Small Craft Advisory (SCA) is now in effect through Wednesday for the typically windy waters around Maui and the Big Island. This SCA will likely need to be extended through the end of the work week and possibly through the weekend.
A series of small northwest swells will move through the islands during the next 7 days, keeping north shore surf from going flat most days.
Fresh to strong trades over and far upstream of the islands will generate trade wind swell that will keep above average surf along east facing shores through Wednesday. Surf will drop to near average levels during the second half of the week into the weekend.
Several overlapping south swells will keep south shore surf elevated today. Surf will then decrease back to seasonal levels Wednesday through Friday, before trending back up over the weekend.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM 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