Hilo

Today: Showers likely, mainly before 1pm. Partly sunny, with a high near 77. North wind 3 to 8 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely, mainly between 7pm and 1am. Mostly cloudy, with a low around 64. North wind 8 to 10 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Showers likely, mainly between 7am and 1pm. Partly sunny, with a high near 77. North northeast wind 6 to 11 mph becoming light north in the afternoon. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Showers likely after noon. Widespread haze. Mostly sunny, with a high near 79. Calm wind becoming southwest around 5 mph. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.

Tonight: Scattered showers, mainly before midnight. Widespread haze. Mostly cloudy, with a steady temperature around 70. Calm wind becoming north northwest around 6 mph after midnight. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers after noon. Widespread haze. Mostly sunny, with a high near 79. West southwest wind around 6 mph. Chance of precipitation is 30%.

Waimea

Today: Scattered showers. Partly sunny, with a high near 74. Northeast wind 3 to 7 mph. Chance of precipitation is 30%. New precipitation amounts between a quarter and half of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 52. East northeast wind 8 to 13 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 74. Breezy, with an east northeast wind around 16 mph, with gusts as high as 22 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kohala

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South Big Island

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Puna

Today: Scattered showers. Partly sunny, with a high near 76. Light north northeast wind becoming north 8 to 13 mph in the morning. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 60. Breezy, with a north wind 13 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 76. Breezy, with a north wind 11 to 16 mph becoming light in the afternoon. Winds could gust as high as 22 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Waikoloa

Today: Isolated showers after noon. Increasing clouds, with a high near 80. East northeast wind around 6 mph becoming light and variable. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 61. East wind 6 to 9 mph. Chance of precipitation is 20%.

Wednesday: Isolated showers after noon. Sunny, with a high near 80. East northeast wind 10 to 13 mph. Chance of precipitation is 20%.

Detailed Forecast

Discussion

The demise of the surface trough near Oahu/Molokai has allow the trade winds, which has been hanging around Kauai for the past few days, to spread east, reaching Maui a short time ago. Breezy northeast trades will spread to Oahu later today, Maui County Wednesday, and finally eastern Big Island on Thursday. Another boost in the trade winds will come on Friday as a strengthening surface high settles in about a thousand miles north and northeast of the islands. The high is expected to reach 1037 mb on Saturday. So, for the islands, it means very wind conditions that will likely warrant a Wind Advisory for the typically windy areas of Maui County and northern Big Island. Other islands/areas could be included. We will evaluate how things are progressing in the next 48 hours. The strong trade winds is expected to collapse Sunday night into Monday as a front approaches the islands from the west.
A series of upper level disturbances will be passing through the islands through Thursday. The first of two impulses will be arriving later this morning, causing an uptick of trade wind showers. The impulse may also lead to a thunderstorm over the Big Island summits this afternoon. The second impulse will be moving through the islands Thursday and Thursday night, lifting the inversion from 10k feet to 15k feet, or an enhancement to the trade wind showers. It won’t be until Saturday afternoon when the inversion lowers back down 10k feet across the entire island chain. Hopefully this is a sign of a drier trade wind pattern.
Weather radar shows a new influx of showers riding in with the trade winds from Maui westward. There will be some wet roads on Kauai and Oahu this morning. There will be a slight drop in trade showers this afternoon, but it will still be wet.

Aviation

As a surface trough near the islands has been dissipating, surface high pressure far to the north-northwest has been taking hold across the area. Trade winds have been persisting over Kauai and adjacent waters, and are now beginning to become reestablished from Oahu to Maui this early morning. And showers have already begun riding on the returning trades and will be mainly focused over windward and mauka sections today. An upper trough heading this way from the northwest will enhance the showers to some extent, along with their accompanying MVFR restrictions. The instability from the upper feature may also trigger isolated thunderstorms over portions of the Big Island by the afternoon hours.
An AIRMET for mountain obscuration remains posted for Kauai, and another AIRMET has been issued over Kauai for low level turbulence below 8000 feet due to the strengthening trades.

Marine

A strong high pressure system northwest of the state will drive fresh to strong trade winds over the western half and moderate trades over the east today. The breezy trades will fill in for all coastal waters tonight and Wednesday. A moderate to large north swell will continue today, then decline tonight. A High Surf Advisory is posted for east facing shores of Kauai, Oahu, Molokai, Maui and Big Island due to exposure to the north swell today and building trade winds through Wednesday. This advisory will likely be extended to the end of the week as winds strengthen and spread to all islands. A small to moderate northwest swell will build later today and linger until the end of the week.
A Small Craft Advisory is is also in effect for the waters surrounding Kauai, Oahu and Maui County due to a combination of winds and seas over the western portion of the state. A couple of the Maui zones drop out tonight as the north swell declines, but will come back Wednesday or Wednesday night and the wind strengthens. Trade winds are expected to build to near gale strength Friday or Saturday, which may prompt the issuance of a Gale Warning for accelerated areas.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Tuesday for Kauai Windward, Oahu Koolau, Olomana, Molokai Windward, Maui Windward West, Windward Haleakala, Big Island North and East.
Small Craft Advisory until 6 AM HST Tuesday for Alenuihaha Channel, Big Island Windward Waters, Big Island Southeast Waters.
Small Craft Advisory until 6 PM HST Tuesday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Pailolo Channel.

Data Courtesy of NOAA.gov