Hilo

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

Tonight: Mostly cloudy. Showers likely in the evening, then occasional showers after midnight. Lows 65 to 70 near the shore to around 52 at 4000 feet. West winds up to 10 mph. Chance of rain 80 percent.

Wednesday: Mostly cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 80 near the shore to 64 to 69 at 4000 feet. Northeast 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 79 to 84 near the shore to around 64 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 68 to 73 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 79 to 84 near the shore to around 64 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 40 percent.

Waimea

Today: Breezy. Mostly cloudy with scattered showers. Highs around 79 near the shore to 64 to 74 near 3000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 67 near the shore to 53 to 60 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Wednesday: Breezy. Mostly cloudy with scattered showers. Highs around 79 near the shore to 64 to 74 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Kohala

Today: Breezy. Mostly cloudy with scattered showers. Highs around 79 near the shore to 64 to 74 near 3000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 67 near the shore to 53 to 60 near 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Wednesday: Breezy. Mostly cloudy with scattered showers. Highs around 79 near the shore to 64 to 74 near 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

South Big Island

Today: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 82 near the shore to around 68 near 5000 feet. Northeast winds 10 to 20 mph shifting to the east up to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 68 near the shore to around 52 near 5000 feet. Northeast winds up to 20 mph becoming 10 to 15 mph after midnight. Chance of rain 20 percent.

Wednesday: Breezy. Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 82 near the shore to around 68 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

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

Tonight: Mostly cloudy. Showers likely in the evening, then occasional showers after midnight. Lows 65 to 70 near the shore to around 52 at 4000 feet. West winds up to 10 mph. Chance of rain 80 percent.

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

Waikoloa

Today: Sunny in the morning then becoming partly sunny. Breezy. Highs around 83 near the shore to 65 to 71 above 4000 feet. East winds up to 20 mph shifting to the northeast in the afternoon. Gusts up to 40 mph.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 68 to 73 near the shore to 49 to 56 above 4000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning then becoming mostly cloudy. Highs around 83 near the shore to 65 to 71 above 4000 feet. East winds up to 15 mph shifting to the north in the afternoon.

Detailed Forecast

Synopsis

Breezy trades will persist through tonight then trend down Wednesday into Thursday, before strengthening again Friday through the weekend. Clouds and showers will favor windward and mountain areas, with a few showers spreading to leeward areas. Increasing moisture combined with an upper disturbance settling southward into the area will result in better windward shower coverage Friday through early next week, with some reaching leeward areas at times.

Discussion

Current radar imagery shows increased shower activity across much of the state's windward areas early this morning, with rainfall amounts highest over Maui and the Big Island ranging from around a quarter to half of an inch. The soundings this morning show a slightly weaker inversion, indicating the start of a weakening in the upper level ridge over the area.
The breezy trade pattern will hold through tonight, before trending down late Wednesday into Thursday as a weakness develops within the ridge north of the state. An upper-level trough is forecast to develop west of the state Wednesday, bringing an increase in high clouds over the area, though no marked change in the typical trade shower pattern or intensity.
For Friday through the weekend, the models are showing the upper- level trough west of the area deepening and moving over the state. Surface high pressure will also strengthen north of the area, which will lead to breezy to locally strong trades. The upper trough combined with increasing moisture will lead to a wet trade wind pattern across the state with some heavy showers possible. Heading into the beginning of next week, models show a decrease in overall moisture as the upper trough weakens and ridging aloft rebuilds, likely bringing a return of typical scattered trade showers.

Aviation

Moderate to locally breezy trade winds will steer low topped clouds and intermittent light showers towards the Islands. Cloud cover will become focused along east and northeast facing slopes and coasts, especially in the late night and morning hours. Brief periods of MVFR CIG or VIS are to be expected in passing showers.
A weak eddy persists just west of the Big Island, keeping the leeward slopes and coasts of the island intermittently engulfed in clouds. Conditions will likely linger into Wednesday.
AIRMET Tango for low level mechanical turbulence to the lee of higher terrain remains in effect. Conditions are expected to persist through 24 hours and likely beyond.

Marine

High pressure far northeast of the islands will gradually shift southeastward into Wednesday. This will maintain a tight enough pressure gradient back across the eastern Pacific to allow locally fresh to moderate trade winds to continue through the day. A Small Craft Advisory (SCA) is in effect for the typically windy waters around Maui County and Big Island into early Wednesday morning. As the high weakens Wednesday and Thursday, trades will follow suit and ease below SCA criteria. The high over the East Pacific will restrengthen Friday as trades return to more fresh magnitudes over the weekend.
Declining overall swell will lead to the lowering of both north and south facing shore surf through Wednesday. The falling northwest swell will cause north shore surf to fall below head high today with a gradual lowering into Wednesday. The arrival of the next small northwest swell this weekend will provide a slight boost to north and west shore surf. A fading south swell will produce lower south facing surf through Wednesday. A small, long period south southwest swell will build in this weekend may pick south surf up by an additional foot or two. Rough east shore surf due to recently fresh to locally strong trade winds will slowly drop off through mid week in response to weakening trades. Restrengthened trades later this week will pick up weekend east wind wave chop.

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