Today: Mostly cloudy. Showers likely and slight chance of thunderstorms in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Locally heavy rainfall possible. Highs 80 to 85 near the shore to 65 to 72 at 4000 feet. South winds up to 10 mph shifting to the east in the afternoon. Chance of rain 70 percent.
Tonight: Mostly cloudy with frequent showers. Lows 64 to 71 near the shore to around 56 at 4000 feet. West winds up to 10 mph. Chance of rain 90 percent.
Friday: Mostly cloudy with numerous showers. Highs 79 to 84 near the shore to 64 to 71 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.
Kona
Today: Mostly sunny. Scattered showers and slight chance of thunderstorms in the afternoon. Locally heavy rainfall possible in the afternoon. Highs around 85 near the shore to around 70 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 40 percent.
Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 69 to 74 near the shore to 50 to 55 near 5000 feet. Light winds. Chance of rain 50 percent.
ARTICLE CONTINUES BELOW AD
ARTICLE CONTINUES BELOW AD
Friday: Sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to around 69 near 5000 feet. Light winds. Chance of rain 50 percent.
Waimea
Today: Partly sunny with scattered showers and slight chance of thunderstorms. Locally heavy rainfall possible. Highs 66 to 85. Northeast winds up to 15 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy. Numerous showers in the evening, then scattered showers after midnight. Lows 64 to 71 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.
Friday: Partly sunny with scattered showers. Highs 65 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.
Kohala
Today: Partly sunny with scattered showers and slight chance of thunderstorms. Locally heavy rainfall possible. Highs 66 to 85. Northeast winds up to 15 mph. Chance of rain 50 percent.
ARTICLE CONTINUES BELOW AD
Tonight: Mostly cloudy. Numerous showers in the evening, then scattered showers after midnight. Lows 64 to 71 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 70 percent.
Friday: Partly sunny with scattered showers. Highs 65 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.
South Big Island
Today: Sunny and breezy. Slight chance of thunderstorms and isolated showers in the afternoon. Locally heavy rainfall possible in the afternoon. Highs around 84 near the shore to around 69 near 5000 feet. East winds 10 to 20 mph decreasing to up to 20 mph in the afternoon. Chance of rain 20 percent.
Tonight: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Scattered showers. Lows around 72 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 40 percent.
Friday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs around 84 near the shore to around 69 near 5000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.
Puna
ARTICLE CONTINUES BELOW AD
Today: Mostly cloudy. Showers likely and slight chance of thunderstorms in the morning, then scattered showers and slight chance of thunderstorms in the afternoon. Locally heavy rainfall possible. Highs 80 to 85 near the shore to 65 to 72 at 4000 feet. South winds up to 10 mph shifting to the east in the afternoon. Chance of rain 70 percent.
Tonight: Mostly cloudy with frequent showers. Lows 64 to 71 near the shore to around 56 at 4000 feet. West winds up to 10 mph. Chance of rain 90 percent.
Friday: Mostly cloudy with numerous showers. Highs 79 to 84 near the shore to 64 to 71 at 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.
Waikoloa
Today: Sunny with a 20 percent chance of thunderstorms. Highs around 84 near the shore to 67 to 73 above 4000 feet. North winds up to 10 mph.
Tonight: Mostly clear with scattered showers. Lows around 73 near the shore to 50 to 56 above 4000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.
Friday: Sunny. Isolated showers in the afternoon. Highs around 84 near the shore to 67 to 72 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.
Detailed Forecast
Synopsis
Weakening high pressure will approach from the northwest, driving moderate trade winds across local waters over the next couple of days. Upper troughs will enhance trade wind showers into Friday, making thunderstorms possible over and around the Big Island through this afternoon. Winds will become strong this weekend as high pressure redevelops northeast of the islands.
Discussion
Models show high pressure will weaken as it approaches the state from the northwest. Expect moderate trade wind flow across local waters through today. Satellite loop shows enhanced clouds sliding westward across windward waters east of Oahu, with a thunderstorm or two lurking just outside coastal waters northeast of Maui and the Big Island. Warmer-topped broken low clouds are poised to move across windward portions of Oahu, Maui and the Big Island later this morning. Scattered low clouds dominate farther to the west.
A shortwave upper trough passing northeast of the Big Island will continue to enhance incoming showers that will impact windward sides of Maui and the Big Island. Molokai and Oahu may be affected to a lesser extent. A second, slightly stronger shortwave upper trough will enhance showers across the same areas tonight into Friday. This second upper trough will also induce a weak surface trough northeast of the state and keep winds moderate into Friday. Some showers could be locally heavy at times. A slight chance of thunderstorms remains in the gridded database for areas on and around the Big Island through this afternoon.
The ridge to the north will restrengthen into a high near 30N150W this weekend and build strong trade winds over the state. While the upper trough departs, clouds and showers will continue to funnel in on the strong trades, reaching many leeward locations of the smaller islands into the first half of next week.
Aviation
A weak surface ridge is located about 330 nm north of PHNL. The relatively close proximity of this feature to the state will produce light to moderate trade winds through this evening. There is some lingering instability and increased moisture over the eastern half of the state. This is causing an enhancement of the low clouds and showers moving into the windward sides of the Big Island, Maui and Molokai. In addition, there is a slight chance of thunderstorms in the vicinity of the windward Big Island. There will likely be periods of MVFR conditions due to lower ceilings and reduced visibilities over portions of windward sides of the eastern and central islands this morning. Low clouds and showers are also starting to increase over windward Oahu early this morning, with brief periods of MVFR conditions possible. Otherwise, VFR conditions are forecast to prevail over most of Kauai, as well as across most leeward areas of the island chain this morning.
An upper-level short wave trough is expected to move from west to east across the state from later today and tonight into Friday. This feature may provide additional atmospheric instability across portions of the island chain as it passes through. Therefore, expect low clouds and brief trade showers to affect most windward sections of the state, including Kauai, from later this afternoon through tonight.
AIRMET Sierra remains in effect for mountain obscuration above 2500 feet along north through east facing sections of Maui. Conditions are expected to gradually improve during the next few hours, so this AIRMET may be lowered later this morning. No additional AIRMETs are anticipated through this afternoon.
Marine
A weak trough developing north of the islands will keep light to locally moderate trades in place through Friday. The trough will dampen out late Friday, allowing moderate trades to rebuild Friday night. The trades will strengthen over the weekend likely bringing Small Craft Advisory level winds to the typically windy waters around Maui and the Big Island on Saturday, then expanding to additional waters Saturday night through Monday as the ridge north of the state strengthens. The trades then appear to ease off again Tuesday through the middle of next week as a cold front approaches from the northwest.
The current north-northwest swell will hold steady just below advisory levels today, then slowly lower tonight through Saturday. The High Surf Advisory (HSA) which was in effect for north facing shores of most of the smaller islands has been cancelled. After a small day up north on Saturday, a new moderate size northwest swell will build Saturday night and Sunday. This swell will peak just below HSA levels Sunday night and Monday, then slowly lower through the middle of next week.
East shore surf will remain small through Friday, increase to near normal over the weekend, then rise to above average levels early next week. The surf along east facing shores is expected to gradually trend lower by the middle of next week as the trades weaken. A small south swell will give south shore surf a small boost today through Friday, before dropping back to very small mainly background levels Saturday through the middle of next week.
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