Photo Credit: James Grenz

Hilo

Today: Scattered showers. Partly sunny, with a high near 83. Light and variable wind becoming east southeast 5 to 8 mph in the afternoon. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely. Cloudy, with a low around 66. South southeast wind around 6 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Thursday: Showers likely, with thunderstorms also possible after noon. Mostly cloudy, with a high near 82. East wind 5 to 9 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Kona

Today: Isolated showers after noon. Mostly cloudy, with a high near 79. West wind 5 to 7 mph becoming calm in the afternoon. Chance of precipitation is 20%.

Tonight: Scattered showers, mainly before midnight. Mostly cloudy, with a low around 65. Light north northwest wind. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Thursday: Scattered showers and thunderstorms after noon. Partly sunny, with a high near 79. West northwest wind 3 to 5 mph. Chance of precipitation is 40%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Waimea

Today: Scattered showers. Partly sunny, with a high near 78. Breezy, with a northeast wind 10 to 15 mph, with gusts as high as 21 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 58. East wind around 10 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Thursday: Scattered showers, with thunderstorms also possible after noon. Partly sunny, with a high near 78. East northeast wind around 10 mph. Chance of precipitation is 50%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Kohala

Today: Scattered showers. Partly sunny, with a high near 64. East wind 7 to 13 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 53. East southeast wind 8 to 11 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Thursday: Showers likely, with thunderstorms also possible after noon. Mostly cloudy, with a high near 64. East wind 11 to 13 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

South Big Island

Today: Isolated showers after noon. Partly sunny, with a high near 84. Windy, with an east wind 20 to 24 mph, with gusts as high as 31 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 74. Breezy, with an east northeast wind 18 to 20 mph, with gusts as high as 25 mph. Chance of precipitation is 20%.

Thursday: Isolated showers, with thunderstorms also possible after noon. Partly sunny, with a high near 84. Breezy, with an east wind 18 to 21 mph, with gusts as high as 26 mph. Chance of precipitation is 20%.

Puna

Today: Scattered showers. Partly sunny, with a high near 82. Light and variable wind becoming east 6 to 11 mph in the afternoon. 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 64. East northeast wind 8 to 10 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

Thursday: Showers likely, with thunderstorms also possible after noon. Mostly cloudy, with a high near 81. East northeast wind 10 to 13 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Waikoloa

Today: Isolated showers after noon. Partly sunny, with a high near 84. East northeast wind 6 to 11 mph becoming light and variable in the afternoon. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 66. Light east wind. Chance of precipitation is 20%.

Thursday: Scattered showers and thunderstorms after noon. Mostly sunny, with a high near 84. North northwest wind 3 to 5 mph. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Detailed Forecast

Synopsis

High pressure north of the state will keep moderate trades in place through Friday, with the trades easing a little over the weekend, and possibly becoming even lighter next week. The remnants of an old front will dampen windward sections of Kauai and Oahu today, with a thunderstorm not out of the question on Kauai. A more typical trade wind pattern will return tonight and hold through early next week, with showers favoring windward and mauka areas and a few showers reaching leeward communities from time to time.

Discussion

Currently at the surface, a 1028 mb high is centered around 1400 miles northeast of Honolulu, and is driving moderate trade winds across the island chain early this morning. Infrared satellite imagery shows a mix of high and low clouds resulting in partly to mostly cloudy conditions across the state, with cloud coverage the highest over Kauai and Oahu. Meanwhile aloft, water vapor imagery shows a broad mid/upper level low a couple hundred miles northwest of Kauai. Radar imagery shows scattered showers moving into windward sections of Kauai, Oahu and the Big Island, with coverage the greatest over Kauai. A few showers are also affecting windward sections of Molokai and Maui, but coverage is much more sparse. Main short term concern revolves around thunder chances the next couple days.
High pressure northeast of the state will lift slowly northward through Friday, keeping moderate trade winds in place across the island chain. A couple fronts approaching and stalling northwest of the islands Saturday through next Tuesday, will suppress the trades down into the light to locally moderate range. The lighter winds will allowing for some localized land and sea breezes to develop during this time as well.
As for the remaining weather details, the remnants of an old front will continue to affect Kauai and Oahu today, bringing showery conditions at times to windward and mauka areas. We will need to keep a slight chance of thunderstorms in the forecast for Kauai through this evening as well due to a disturbance aloft moving overhead while the old frontal remnants move through. Meanwhile across Maui County and the Big Island, a fairly dry trade wind pattern will prevail, although shower coverage will be a bit higher over windward Big Island.
A more typical trade wind pattern will resume tonight and hold in place through early next week. Clouds and showers will favor windward and mauka areas, particularly at night and during the early morning hours, with a few showers spilling leeward at times as well. A few showers may also develop each afternoon over leeward areas in the lightened trade wind regime Saturday through next Tuesday. Some lingering instability may allow for a thunderstorm or two to pop on the Big Island Thursday afternoon as well.

Aviation

Moderate easterly trades will concentrate most shower activity along the windward coasts and slopes through this afternoon. In addition, a moisture boundary will act to increase shower activity for Oahu and Kauai.
Relatively unstable air aloft will lead to a slight chance of thunderstorms over Kauai and surrounding waters.
No AIRMETs are currently in effect.

Marine

High pressure north of the islands will maintain moderate to locally strong trade winds through Friday. Showers activity will remain elevated over the northern waters today and may produce a few isolated thunderstorms around Kauai waters. A Small Craft Advisory is in effect through Thursday afternoon for the windier waters near Maui and the Big Island. Trade winds are expected to decrease over the weekend as a front develops well northwest of the state.
Surf along south facing shores will remain small today, then slowly rise and approach High Surf Advisory levels over the weekend, and slowly decline into next week. Surf along north facing shores will be minimal through the rest of the week, but a small northwest swell is possible Sunday and could remain into next week. Trade winds upstream of the islands will produce small to moderate choppy surf along east facing shores through the period.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Thursday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov