Photo Credit: James Grenz

Hilo

Today: Mostly cloudy with scattered showers. Highs 78 to 83 near the shore to 66 to 71 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 69 near the shore to 52 to 57 at 4000 feet. Light winds. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 78 to 84 near the shore to 66 to 72 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 81 to 86 near the shore to around 68 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 67 to 72 near the shore to 46 to 54 near 5000 feet. Light winds. Chance of rain 30 percent.

Wednesday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 81 to 87 near the shore to around 68 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.

Waimea

Today: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 66 to 85. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 63 near the shore to 52 to 60 near 3000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 65 to 85. East winds up to 20 mph. Chance of rain 50 percent.

Kohala

Today: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 66 to 85. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows around 63 near the shore to 52 to 60 near 3000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 65 to 85. East winds up to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 82 near the shore to around 67 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Scattered showers. Lows around 70 near the shore to around 49 near 5000 feet. Northeast winds up to 20 mph. Chance of rain 40 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs around 82 near the shore to around 68 near 5000 feet. East winds up to 25 mph. Chance of rain 50 percent.

Puna

Today: Mostly cloudy with scattered showers. Highs 78 to 83 near the shore to 66 to 71 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 69 near the shore to 52 to 57 at 4000 feet. Light winds. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 78 to 84 near the shore to 66 to 72 at 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Today: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 80 to 85 near the shore to 65 to 71 above 4000 feet. Southeast winds up to 10 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 65 to 73 near the shore to 47 to 54 above 4000 feet. Light winds becoming southeast up to 10 mph after midnight. Chance of rain 20 percent.

Wednesday: Sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 80 to 86 near the shore to 66 to 72 above 4000 feet. East winds up to 15 mph shifting to the north in the afternoon. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Light east to southeast trade winds will continue through Wednesday, and some moisture moving in from the southeast could boost rainfall chances for the Big Island and Maui today and possibly across the state on Wednesday. A dry trade wind pattern will return Thursday through Saturday, with trades potentially becoming disrupted Sunday as a front approaches.

Discussion

Guidance remains in good agreement and shows the trades remaining light through midweek as a front passes to the north. The low- level flow has responded and veered out of the southeast, which is drawing up a decent-sized area of enhanced low-level moisture over the Big Island this morning. This area will move up the island chain to Maui County today, then to the western end of the state tonight through Wednesday. Expect a slight increase in rainfall chances over the southeast slopes of the Big Island and Maui, as well as their leeward and interior sections each afternoon where sea breezes form. Rainfall accumulations should remain light due to a combination of plenty of mid-level dry air and an upper ridge holding over the area. For the rest of the state, a hybrid trade wind/land and sea breeze pattern is expected with light rainfall favoring windward slopes at night and leeward terrain in the afternoon.
A return to somewhat dry trade wind weather is due on Thursday as the enhanced moisture clears the islands. The GFS and ECMWF are showing a weak upper level trough passing overhead Thursday and Friday. This feature should produce an increase in high clouds, but no other impacts to local weather are expected at this time.
In the extended forecast, an approaching front will disrupt the trade winds Sunday into Monday. Although confidence remains low being this far out in time, a transition to a wet pattern can't be ruled out for early next week. More details will follow as the week progresses and confidence increases.

Aviation

Weak surface ridging remains north of the area and will sustain light to locally moderate east to southeast winds across the state through tonight. There will also be sections of the island chain that see daytime sea breezes and nighttime land breezes, especially over the western half. Isolated to locally scattered showers will mainly affect the Big Island and Maui beginning today as an area of moisture moves in from the southeast, though most locales will remain VFR.
There are no AIRMETs in effect, but one for mountain obscuration in windward sections of the Big Island may be needed later this morning.

Marine

A ridge of high pressure will remain north of the state over the next few days and will lead to moderate trade winds. As the ridge shifts further north during the second half of the week, trade winds are expected to increase to fresh speeds. Winds may weaken on Sunday and veer towards the southeast as a front approaches from the northwest
The current northwest swell has dropped below advisory thresholds and will continue to gradually decline and veer toward the north- northwest over the next few days. A series of smaller northwest swells are expected Thursday through Saturday with surf peaking below High Surf Advisory thresholds. A large northwest swell is possible around next week Tuesday.
South facing shores are forecast to have small, background swells through the week. A small south swell is possible towards the middle of next week (23rd). East facing shores will have small, choppy surf through the week due to the general weakness of the trades upwind from the state.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov