Hilo

Tonight: Mostly cloudy with scattered showers. Lows 63 to 70 near the shore to 52 to 58 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 30 percent.

Wednesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 85 near the shore to 64 to 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 40 percent.

Wednesday Night: Numerous showers in the evening, then frequent showers after midnight. Lows 64 to 70 near the shore to 54 to 59 at 4000 feet. West winds up to 10 mph. Chance of rain near 100 percent.

Kona

Tonight: Partly cloudy. Lows around 73 near the shore to 47 to 52 near 5000 feet. East winds up to 10 mph in the evening becoming light.

Wednesday: Mostly sunny. Isolated showers in the afternoon. Highs around 86 near the shore to around 68 near 5000 feet. South winds up to 10 mph shifting to the west in the afternoon. Gusts up to 35 mph. Chance of rain 20 percent.

Wednesday Night: Partly cloudy. Isolated showers after midnight. Lows around 73 near the shore to 48 to 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Windy. Partly cloudy with isolated showers. Lows 64 to 72 near the shore to 54 to 62 near 3000 feet. East winds up to 30 mph with gusts to 50 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 64 to 84. East winds up to 25 mph with gusts to 45 mph. Chance of rain 40 percent.

Wednesday Night: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 64 to 72 near the shore to 56 to 62 near 3000 feet. East winds up to 25 mph. Chance of rain 70 percent.

Kohala

Tonight: Windy. Partly cloudy with isolated showers. Lows 64 to 72 near the shore to 54 to 62 near 3000 feet. East winds up to 30 mph with gusts to 50 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 64 to 84. East winds up to 25 mph with gusts to 45 mph. Chance of rain 40 percent.

Wednesday Night: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 64 to 72 near the shore to 56 to 62 near 3000 feet. East winds up to 25 mph. Chance of rain 70 percent.

South Big Island

Tonight: Mostly clear. Windy. Lows around 74 near the shore to around 50 near 5000 feet. Northeast winds 10 to 30 mph.

Wednesday: Sunny and windy. Highs around 86 near the shore to around 68 near 5000 feet. East winds up to 30 mph increasing to 15 to 30 mph in the afternoon.

Wednesday Night: Breezy. Partly cloudy in the evening, then mostly cloudy with numerous showers after midnight. Lows around 75 near the shore to around 52 near 5000 feet. Northeast winds 10 to 25 mph. Chance of rain 70 percent.

Puna

Tonight: Mostly cloudy with scattered showers. Lows 63 to 70 near the shore to 52 to 58 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 30 percent.

Wednesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 79 to 85 near the shore to 64 to 69 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 40 percent.

Wednesday Night: Numerous showers in the evening, then frequent showers after midnight. Lows 64 to 70 near the shore to 54 to 59 at 4000 feet. West winds up to 10 mph. Chance of rain near 100 percent.

Waikoloa

Tonight: Mostly clear. Breezy. Lows around 73 near the shore to 50 to 55 above 4000 feet. Southeast winds up to 25 mph with gusts to 45 mph.

Wednesday: Sunny and breezy. Highs 84 to 89 near the shore to 65 to 73 above 4000 feet. Northeast winds up to 25 mph with gusts to 45 mph.

Wednesday Night: Partly cloudy. Breezy. Isolated showers after midnight. Lows around 74 near the shore to 51 to 56 above 4000 feet. Southeast winds up to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Fresh to locally strong trade winds will carry in brief clouds and showers over the islands. Showers increase Wednesday night through Friday night as a midlevel trough moves through, while winds taper off Thursday night into Friday. A drier trend is expected this weekend with strengthening trade winds.

Discussion

Fresh to locally strong trade winds will continue through Thursday under a broad high pressure ridge. An advancing cold front well north of Hawaii will move the driving high pressure system further from the islands resulting in a slight weakening of the wind speeds Thursday night. Meanwhile, a nearly stationary deep low pressure system will set up northwest of Hawaii. Both the distant front and low will keep winds moderate and slightly veered east southeasterly from Thursday into Friday. Island terrain blockage under this wind regime will further weaken the winds across leeward areas, resulting in localized sea breezes and interior clouds Friday afternoon before the trade winds strengthen back this weekend.
Trades will carry in brief clouds and showers over the islands through Wednesday. A midlevel trough will move onto the windward and southeast Big Island Wednesday night and spread westward during the second half of the week. This feature will bring an increase in clouds and showers through Friday night. A weak upper level low moving into position northeast of the state during this time may also enhance the incoming showers. The forecast will trend drier with a continuation of the moderate east southeast flow from Saturday into the middle of next week.

Aviation

Breezy easterly trade winds will focus limited low clouds and showers over windward and mountain areas through tomorrow. As is typical in a drier trade wind pattern, shower coverage will be isolated through early this evening, increase a bit overnight into the early morning hours, then thin out again tomorrow afternoon. While brief MVFR conditions will be possible in any heavier showers overnight, VFR conditions are expected to prevail.
AIRMET Tango for moderate low-level turbulence downwind of island terrain is in effect due to the strengthening easterly trade winds. This AIRMET will likely be needed through tomorrow.

Marine

Fresh to strong trades will strengthen a touch tonight in response to strengthening high pressure north of the ara. The Small Craft Advisory (SCA) is now in effect through tonight for all waters due to winds and/or elevated seas. As seas gradually subside tonight, the SCA will be allowed to expire for nearshore waters north and west of Oahu but will remain in effect elsewhere as strong trades persist.
Existing N (350) moderate, medium swell has been modeled to slowly subside through today. After hovering around 2 feet above guidance throughout the day, NDBC buoys 51001, 51101, and 51000 have shown signs of subsiding N swell late this afternoon. Meanwhile, the Hanalei PACIOOS buoy still indicates High Surf Advisory conditions going strong at press time. Surf should begin to noticeably subside during the next few hours. However, the High Surf Advisory will be extended through tonight mainly to capture the trailing end of the high surf period during the first half of the overnight period.
Surf along west facing shores remains slightly elevated with the influence of the north swell during the next couple days. Surf along E shores increases today and Wednesday in response to short period trade wind swell over and upstream of the islands. Surf then declines in concert with weakening trades during the latter half of the week. However, east facing shores exposed to the north swell will continue to see some wrap during the next couple days. South shore surf will remain small with mainly background south and southeast swells during the next 7 days.

HFO Watches/Warnings/Advisories

Wind Advisory until 6 AM HST Wednesday for Big Island Summits.
High Surf Advisory until 6 AM HST Wednesday for Niihau, Kauai, Oahu, Molokai, Maui and Big Island.
Small Craft Advisory until 6 PM HST Wednesday for Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory until 6 AM HST Wednesday for remaining coastal waters.

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Data Courtesy of NOAA.gov