Today: Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 75 to 82 near the shore to 58 to 66 at 4000 feet. Northeast winds up to 20 mph. Chance of rain near 100 percent.
Tonight: Mostly cloudy. Showers likely in the evening, then frequent showers after midnight. Lows 60 to 68 near the shore to 51 to 56 at 4000 feet. Northwest winds up to 15 mph shifting to the northeast after midnight. Chance of rain 90 percent.
Thursday: Mostly cloudy. Frequent showers early in the morning, then scattered showers in the late morning and afternoon. Highs 75 to 82 near the shore to 60 to 67 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 90 percent.
Kona
Today: Sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 82 to 87 near the shore to around 66 near 5000 feet. Light winds becoming west up to 10 mph in the afternoon. Chance of rain 40 percent.
Tonight: Mostly cloudy with scattered showers in the evening, then mostly clear with isolated showers after midnight. Lows around 70 near the shore to 44 to 52 near 5000 feet. Light winds becoming east up to 10 mph after midnight. Chance of rain 50 percent.
ARTICLE CONTINUES BELOW AD
ARTICLE CONTINUES BELOW AD
Thursday: Sunny in the morning then becoming partly sunny. Isolated showers. Highs 82 to 87 near the shore to around 67 near 5000 feet. East winds around 10 mph shifting to the northwest in the afternoon. Chance of rain 20 percent.
Waimea
Today: Windy. Frequent showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 77 near the shore to 64 to 75 near 3000 feet. East winds 10 to 30 mph with gusts to 50 mph. Chance of rain near 100 percent.
Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows 61 to 69 near the shore to 50 to 59 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 70 percent.
Thursday: Mostly cloudy. Breezy. Showers likely early in the morning, then scattered showers in the late morning and afternoon. Highs around 77 near the shore to 65 to 75 near 3000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.
Kohala
Today: Windy. Frequent showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 77 near the shore to 64 to 75 near 3000 feet. East winds 10 to 30 mph with gusts to 50 mph. Chance of rain near 100 percent.
ARTICLE CONTINUES BELOW AD
Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows 61 to 69 near the shore to 50 to 59 near 3000 feet. East winds 10 to 25 mph with gusts to 45 mph. Chance of rain 70 percent.
Thursday: Mostly cloudy. Breezy. Showers likely early in the morning, then scattered showers in the late morning and afternoon. Highs around 77 near the shore to 65 to 75 near 3000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.
South Big Island
Today: Windy. Sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 84 near the shore to around 66 near 5000 feet. East winds up to 30 mph increasing to 10 to 30 mph in the afternoon. Gusts up to 50 mph. Chance of rain 20 percent.
Tonight: Breezy. Mostly cloudy with isolated showers in the evening, then mostly clear after midnight. Lows around 72 near the shore to around 49 near 5000 feet. Northeast winds 10 to 20 mph. Chance of rain 20 percent.
Thursday: Mostly sunny. Breezy. Highs around 84 near the shore to around 66 near 5000 feet. East winds 10 to 20 mph.
Puna
ARTICLE CONTINUES BELOW AD
Today: Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 75 to 82 near the shore to 58 to 66 at 4000 feet. Northeast winds up to 20 mph. Chance of rain near 100 percent.
Tonight: Mostly cloudy. Showers likely in the evening, then frequent showers after midnight. Lows 60 to 68 near the shore to 51 to 56 at 4000 feet. Northwest winds up to 15 mph shifting to the northeast after midnight. Chance of rain 90 percent.
Thursday: Mostly cloudy. Frequent showers early in the morning, then scattered showers in the late morning and afternoon. Highs 75 to 82 near the shore to 60 to 67 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 90 percent.
Waikoloa
Today: Mostly sunny. Windy. Scattered showers in the morning. Highs 81 to 87 near the shore to 63 to 68 above 4000 feet. Northeast winds up to 35 mph with gusts to 60 mph. Chance of rain 50 percent.
Tonight: Partly cloudy. Windy. Lows 68 to 73 near the shore to 46 to 53 above 4000 feet. East winds up to 30 mph.
Thursday: Mostly sunny. Highs 81 to 86 near the shore to around 66 above 4000 feet. Northeast winds 10 to 15 mph.
Detailed Forecast
Synopsis
Today's strong trade winds will gradually ease Thursday and Friday, delivering low clouds and showers that will favor windward slopes and coasts, especially during nights and mornings. Some light showers will also spread leeward at times with the strong trades. Winds will become light and turn southerly on Saturday as a front approaches. The front is expected to arrive on Sunday, potentially bringing increased showers to leeward areas. Light winds will prevail next week.
Discussion
Strong high pressure due N of the islands is supporting a strong and relatively cool ENE trade wind flow this morning. A Wind Advisory remains posted for areas in Maui and Hawaii Counties where winds are most accelerated by terrain. Although the island atmosphere is quite stable with a strong subsidence inversion based around 8 thousand feet and below-normal PWAT near 1″, steep low-level lapse rates below the inversion are allowing highly efficient warm rain processes to drive the formation of quite a few showers. Radar shows scattered to numerous small showers moving over the islands while satellite imagery shows scattered to broken open-celled (aka showery) low clouds approaching the islands from the ENE.
The high will weaken while moving closer to the islands over the next couple of days, resulting in a slow decrease in trade wind speeds. Model guidance indicates little overall change to the incoming low-level moisture field, so passing showers will favor windward areas during nights and mornings through Friday, with fewer showers spreading leeward as trades ease.
Late Friday, the weakened high will move NE in response to strong cyclogenesis NW of the area. Winds will briefly become light S/SW Saturday as an associated front approaches from the NW. The front is not expected to be particularly strong, but will likely bring some showers as it moves SE down the chain Sunday/Monday. Although some cold advection in the form of moderate N/NE winds may occur immediately after the front passes, winds are expected to diminish rapidly thereafter as the front dissipates over, or just E of, the islands early next week.
Aviation
Locally strong trades will persist through the forecast period. Enhanced low level moisture will bring scattered to numerous showers to the windward sides of all islands this morning, then decrease in coverage by this afternoon. Periods of MVFR ceilings and visibility will likely accompany this activity. In addition, isolated may push over the terrain and affect leeward locations.
AIRMET SIERRA remains in effect for north through east sections of the Big Island for tempo mountain obscuration above 3000 ft.
AIRMET TANGO remains in effect for low-level moderate turbulence over and downwind of the mountains of all islands due to locally strong trades.
Marine
Strong northeast to east trades with near gales over the channels and windier waters around Maui and the Big island will continue today as strong high pressure remains positioned to the north. These winds combined with a large area of strong- to gale-force northeast winds focused at the state between this high and low pressure far northeast of the area support rough seas with heights hovering above the Small Craft Advisory level over exposed waters into Thursday.
Guidance shows the gradient beginning to relax Thursday through Friday as high pressure north of the area settles southward and weakens, which will result in the local winds returning to the fresh to locally strong range. Over the weekend, the progressive pattern over the northern Pacific will continue as low pressure rapidly develops northwest of the state Friday, then lifts northeastward while passing to the north around 1000 NM. A front associated with this feature will approach and potentially reach the western end of the state by the end of the weekend. If this evolves as predicted, moderate south to southwest winds will become a possibility as the front approaches.
Surf along exposed north and east facing shores will remain rough into the second half of the week due to a mix of the locally wind- generated seas and a northeast groundswell from the aforementioned fetch upstream. Heights will hover around the High Surf Advisory criteria for east facing shores into Thursday. A reinforcing swell arriving out of the same direction (050 deg) Friday could be enough to support advisory-level surf returning for eastern exposures. A downward trend is anticipated over the weekend as the winds shift out of the south.
Surf along north and west facing shores will rise over the weekend as a small, long-period north-northwest swell arrives and moves through. A more significant event is possible Sunday night through early next week due to a large area of northerly gales forecast to develop nearby on the backside of the rapidly developing low passing around 1000 NM to the north this weekend. Heights with these nearby northerly sources typically come in much larger than predicted, which could lead to advisory to warning-level surf early next week.
Surf along south facing shores will trend up over the weekend as a long-period south swell arrives.
HFO Watches/Warnings/Advisories
High Surf Advisory until 6 PM HST Thursday for East facing shores of Kauai Oahu Molokai Maui and the Big Island.
Wind Advisory until 6 PM HST this evening for Lanai Mauka, Kahoolawe, Maui Windward West, Maui Leeward West, Kohala, Big Island Interior, Lanai Windward, Lanai Leeward, Lanai South, Maui Central Valley North, Maui Central Valley South, South Haleakala, Big Island South, Big Island Southeast, Big Island North.
Small Craft Advisory until 6 PM HST Thursday for all Hawaiian waters.
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