Hawaii County Weather Forecast for July 09, 2021
Hilo
Today: Scattered showers, mainly before noon. Partly sunny, with a high near 84. Calm wind becoming east 5 to 9 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.
Tonight: Scattered showers. Mostly cloudy, with a low around 66. East wind 5 to 9 mph becoming light and variable. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.
Saturday: Scattered showers. Mostly cloudy, with a high near 84. Light and variable wind becoming east 5 to 9 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.
Kona
Today: Scattered showers after noon. Partly sunny, with a high near 80. East wind 6 to 9 mph becoming west southwest in the morning. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.
Tonight: Scattered showers, mainly before midnight. Mostly cloudy, with a low around 65. Northwest wind 6 to 10 mph becoming east in the evening. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.
Saturday: Scattered showers after noon. Partly sunny, with a high near 80. East wind 6 to 10 mph becoming west northwest in the morning. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.
Waimea
Today: Scattered showers. Partly sunny, with a high near 79. Breezy, with a northeast wind 14 to 16 mph, with gusts as high as 23 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.
Tonight: Scattered showers. Mostly cloudy, with a low around 58. Northeast wind 10 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 30%. New precipitation amounts between a tenth and quarter of an inch possible.
Saturday: Scattered showers. Partly sunny, with a high near 79. Breezy, with a northeast wind 10 to 18 mph, with gusts as high as 26 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.
Kohala
Today: Scattered showers, mainly before noon. Partly sunny, with a high near 65. East wind 7 to 10 mph. Chance of precipitation is 30%.
Tonight: Scattered showers. Mostly cloudy, with a low around 53. Breezy, with an east wind 10 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.
Saturday: Scattered showers. Mostly cloudy, with a high near 65. Breezy, with an east wind 16 to 20 mph, with gusts as high as 28 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.
South Big Island
Today: Mostly sunny, with a high near 85. Breezy, with an east wind 20 to 22 mph, with gusts as high as 28 mph.
Tonight: Isolated showers. Mostly cloudy, with a low around 74. Breezy, with an east northeast wind 20 to 22 mph, with gusts as high as 28 mph. Chance of precipitation is 20%.
Saturday: Isolated showers. Partly sunny, with a high near 85. Windy, with an east wind 18 to 24 mph, with gusts as high as 31 mph. Chance of precipitation is 20%.
Puna
Today: Scattered showers. Partly sunny, with a high near 83. West wind 6 to 11 mph becoming east in the afternoon. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.
Tonight: Scattered showers. Mostly cloudy, with a low around 64. East wind 6 to 11 mph becoming light and variable. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.
Saturday: Scattered showers. Mostly cloudy, with a high near 83. West wind 5 to 11 mph becoming east in the morning. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.
Waikoloa
Today: Isolated showers after noon. Mostly sunny, with a high near 85. East wind 9 to 13 mph becoming west northwest in the afternoon. Chance of precipitation is 20%.
Tonight: Scattered showers before midnight. Mostly cloudy, with a low around 66. West northwest wind 5 to 11 mph becoming east in the evening. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.
Saturday: Scattered showers after noon. Partly sunny, with a high near 85. East wind 5 to 11 mph becoming northwest in the morning. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.
Detailed Forecast
Synopsis
Light to moderate trade winds will continue to deliver a few showers to windward areas through Saturday, with localized sea breezes allowing for the development of a few showers each afternoon in leeward locales. A more typical moderate to breezy trade wind pattern will return by Sunday with showers favoring windward and mauka areas, particularly at night and during the early morning hours, with a stray shower reaching leeward areas from time to time.
Discussion
Currently at the surface, a weak southwest to northeast oriented trough of low pressure remains nearly stationary around 300 miles north of Kauai. Meanwhile, a 1032 mb high is centered to the distant northwest of the islands and a 1024 mb high is located to the distant northeast. Light to moderate trades prevail across the island chain early this morning, with some localized land breezes in the more sheltered leeward areas. Infrared satellite imagery shows clear to partly cloudy skies in most areas, with a bit more cloud cover over Kauai. Radar imagery shows a few light showers moving into windward areas, with coverage the highest over Kauai, with mainly rain free conditions in leeward locales. Main short term concerns revolve around trade wind trends and rain chances during the next couple days.
The surface trough to the north of the islands will shift westward during the next few days, while high pressure to the distant northeast strengthens and builds westward toward the state. We expect the light to moderate trade wind pattern and localized leeward sea and land breezes to hold in place through Friday night. We should then see the trades strengthen from east to west across the state on Saturday, with moderate to breezy trades then expected Sunday through much of next week.
As for the remaining weather details, similar weather should prevail through Saturday, with mainly windward showers at night and during the morning hours, and a few daytime heating driven showers developing over leeward areas each afternoon, with these showers then fizzling out in the evening. A transition back to more typical trade wind weather should take hold Saturday night and continue through much of next week, with showers favoring windward and mauka areas, particularly at night and during the early morning hours, with a stray shower spilling over into leeward communities from time to time.
Aviation
Light to moderate easterly trades will persist trough the remainder of this morning. Scattered showers will mainly be confined to windward areas of the Big Island and Kauai with isolated activity elsewhere. There may be brief periods of MVFR ceilings and visibility, but not expecting anything widespread.
There are currently no AIRMETs in effect.
Marine
Weak surface troughing north of the state will be moving west the next couple of days while a ridge of high pressure builds in northeast of the islands. This will maintain generally moderate easterly trade winds that could slightly veer southeast and strengthen through the weekend. As the trough moves far northwest of the islands and high pressure to the north tightens the gradient over the state early next week, strengthened easterlies will back to more typical northeast trade flow Sunday. Moderate to locally strong trades are then expected to continue through early next week. Small Craft Advisory level winds will likely occur over the windier areas surrounding Maui County and the Big Island southern waters beginning Saturday. These locally strong trades could persist through the middle of next week.
The recent long-lived south swell will continue its slow fall with south facing shore surf holding steady through Saturday. Stronger trade winds will increase short period wind waves along many eastern exposures from this weekend into early next week. A gale passing east of New Zealand is sending the next appreciable swell northward within Hawaii’s southern swell window. These longer period south swells may arrive to boost southern surf by the end of next week.
HFO Watches/Warnings/Advisories
None.
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Data Courtesy of NOAA.gov