West Side

Tonight: Partly cloudy. Haze. Lows 65 to 72. South winds up to 10 mph shifting to the southeast after midnight.

Wednesday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Haze through the day. Highs 76 to 82. Southwest winds up to 15 mph. Chance of rain 30 percent.

Wednesday Night: Mostly cloudy. Isolated showers in the evening. Haze through the night. Lows 65 to 72. Light winds. Chance of rain 20 percent.

South Side

Tonight: Partly cloudy. Haze. Lows 64 to 74. West winds up to 15 mph in the evening becoming light.

Wednesday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Haze through the day. Highs around 83. Southwest winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Wednesday Night: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Haze through the night. Lows 62 to 74. Southwest winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

North Shore

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Haze. Lows around 68 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Haze through the day. Highs 77 to 83 near the shore to around 66 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy with isolated showers. Haze. Lows around 68 near the shore to around 50 near 5000 feet. Light winds. Chance of rain 20 percent.

Central Maui

Tonight: Partly cloudy. Haze. Lows around 66. South winds up to 10 mph shifting to the east after midnight.

Wednesday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Haze through the day. Highs 79 to 85. Southwest winds up to 15 mph. Chance of rain 20 percent.

Wednesday Night: Mostly cloudy. Isolated showers in the evening. Haze through the night. Lows around 65. South winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Upcountry

Tonight: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Haze through the night. Lows around 45 at the visitor center to around 49 at the summit. East winds up to 10 mph. Chance of rain 20 percent.

Wednesday: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Haze through the day. Highs around 61 at the visitor center to around 69 at the summit. Southeast winds up to 10 mph. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Haze through the night. Lows around 44 at the visitor center to around 47 at the summit. Light winds. Chance of rain 20 percent.

East Maui

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Haze. Lows around 68 near the shore to around 50 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Haze through the day. Highs 77 to 83 near the shore to around 66 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Wednesday Night: Mostly cloudy with isolated showers. Haze. Lows around 68 near the shore to around 50 near 5000 feet. Light winds. Chance of rain 20 percent.

Lanai City

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Haze through the night. Lows around 63. Light winds. Chance of rain 40 percent.

Wednesday: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Haze through the day. Highs 72 to 79. Southwest winds up to 15 mph. Chance of rain 30 percent.

Wednesday Night: Partly cloudy. Haze. Lows around 63. Light winds.

Kaunakakai

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Haze through the night. Lows 55 to 71. Light winds becoming east up to 10 mph after midnight. Chance of rain 50 percent.

Wednesday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Haze through the day. Highs 70 to 84. Southeast winds up to 10 mph shifting to the southwest in the afternoon. Chance of rain 40 percent.

Wednesday Night: Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Haze through the night. Lows 55 to 71. Light winds. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Rain chances will steadily increase through the week especially over the western half of the state as a frontal boundary moves over Kauai and stalls near Oahu Thursday into Friday. Breezy to locally strong trade winds should return on Friday with a showery trade wind pattern expected through the weekend. Once again, the trade wind showers should be most frequent over the western half of the state.

Discussion

Forecast remains on track and no changes have been made for the evening update. Light to moderate south to southeasterly winds will weaken some Wednesday but the wind direction will continue to remain out of the south or southeast. With the ongoing eruption of Kilauea and the southeasterly winds over the Big Island, we have had reports of Pele's hair falling onto Highway 11. The southeasterly winds should weaken this evening with land breezes developing overnight tonight. Southeasterly winds will likely develop during the day on Wednesday and with the general southeasterly flow, more widespread vog will be possible on Wednesday.
A frontal boundary currently located west of Kauai will slowly shift eastward over the next few days. Satellite imagery this evening continues to show a broad NE to SW oriented line of showers and thunderstorms roughly 180 miles west of Kauai. This line of heavier showers is expected to slowly move east and gradually weaken as it approaches Kauai Wednesday into Thursday. Starting Wednesday as the frontal boundary nears Kauai, we could begin to see some heavier showers especially during the afternoon over the western half of the state. There are still quite a bit of uncertainty for precipitation amounts on Wednesday due to the uncertainty in the location of the frontal boundary. GFS ensembles brings the frontal boundary very close to Kauai, while the EC and Canadian ensemble members keeps the bulk of the moisture slightly further west of Kauai. Thus, the precipitation amounts still remain uncertain for Wednesday over Kauai and Oahu, but off and on scattered showers should be expected. For rest of the state, isolated to scattered showers will be possible on Wednesday with mostly light rainfall amounts.
On Thursday, there is better agreement with global models with the frontal boundary reaching Kauai. This should allow for some moderate to locally heavy showers over Kauai and Oahu. With generally light winds on Thursday, any showers will be slow moving and we could see some flooding concerns especially over north Kauai. The frontal boundary is expected to weaken and stall somewhere around Kauai or Oahu on Friday. Breezy to locally strong trade winds will also return on Friday with a showery trade wind pattern expected across the state over the weekend. The greatest moisture will once again continue to be across the western half of the state, especially Kauai. So overall, showery weather should be expected over Kauai and possibly Oahu from Thursday through the weekend. Passing showers should also increase for the eastern half of the state once the trade winds return.

Aviation

Moderate southerly winds will continue tonight over the western half of the state as a cold front approaches from the northwest. Expect an uptick in shower activity across Kauai and Oahu as moisture streams in from the south ahead of the front, with periods of MVFR likely with the heavier showers.
Otherwise, the eastern half of the state will see moderate to locally breezy southeasterly winds continue into Wednesday, with localized sea breezes in sheltered areas. Conditions should remain mainly VFR.
No AIRMETs are currently in effect, but AIRMET Sierra for tempo mountain obscuration may be needed for Kauai and Oahu as showers become more widespread.
All areas will continue to see some Vog due to the ongoing eruption of Kilauea. However, the Vog is not expected to impact visibilities enough to warrant a mention in any TAF.

Marine

A cold front, slowly approaching the islands from the west, will maintain breezy southeasterly flow across the eastern portion of the state and light to moderate southerly flow elsewhere. A Small Craft Advisory (SCA) remains in effect through Wednesday morning for waters around the Big Island for local wind acceleration around and along the parallel coastlines to the wind direction. This advisory may need to be extended through Wednesday afternoon as these winds gradually ease throughout the day. As the aforementioned front moves across the smaller islands and dissipates, moderate to locally strong northeast trades are expected to develop this weekend and early next week.
A moderate north-northwest (330-350) swell is expected to arrive on Friday and could produce advisory level surf. A large to extra large, long period, north to north-north west (340-360) swell is forecast to arrive this weekend and would likely produce warning level surf along north facing shores with advisory level surf across west and east facing shores. This swell, aside from being hazardous to small craft, could generate harbor surges along north facing bays and inlets.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Wednesday for Big Island Windward Waters, Big Island Leeward Waters.

Data Courtesy of NOAA.gov