Hawaii County Weather Forecast for July 29, 2021
Hilo
Today: Frequent showers, mainly before noon. High near 83. Calm wind becoming northeast 5 to 9 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.
Tonight: Showers likely. Cloudy, with a low around 71. Light and variable wind becoming west northwest around 5 mph after midnight. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Friday: Showers likely, mainly before noon. Cloudy, with a high near 83. East northeast wind 6 to 11 mph becoming light and variable in the afternoon. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Kona
Today: Scattered showers after noon. Mostly cloudy, with a high near 81. Light and variable wind becoming west 5 to 10 mph in the morning. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.
Tonight: Isolated showers. Mostly cloudy, with a low around 71. Northwest wind 5 to 7 mph becoming calm after midnight. Chance of precipitation is 20%.
Friday: Isolated showers. Partly sunny, with a high near 81. Calm wind becoming west 5 to 8 mph. Chance of precipitation is 20%.
Waimea
Today: Scattered showers, mainly before 1pm. Mostly cloudy, with a high near 76. Windy, with a northeast wind 17 to 23 mph, with gusts as high as 32 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.
Tonight: Scattered showers, mainly after 7pm. Mostly cloudy, with a low around 58. Breezy, with a northeast wind 20 to 22 mph, with gusts as high as 31 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.
Friday: Scattered showers, mainly before 1pm. Mostly cloudy, with a high near 76. Windy, with a northeast wind 17 to 24 mph, with gusts as high as 34 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.
Kohala
Today: Showers likely, mainly before noon. Cloudy, with a high near 67. Windy, with an east wind 18 to 24 mph, with gusts as high as 34 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Tonight: Showers likely, mainly before 11pm. Cloudy, with a low around 53. Windy, with an east wind 21 to 26 mph, with gusts as high as 38 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Friday: Scattered showers, mainly before noon. Cloudy, with a high near 67. Windy, with an east wind 18 to 25 mph, with gusts as high as 36 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.
South Big Island
Today: Partly sunny, with a high near 83. Windy, with an east wind 23 to 26 mph, with gusts as high as 34 mph.
Tonight: Partly cloudy, with a low around 74. Windy, with an east wind 23 to 26 mph, with gusts as high as 34 mph.
Friday: Mostly sunny, with a high near 83. Windy, with an east wind 23 to 28 mph, with gusts as high as 36 mph.
Puna
Today: Frequent showers, mainly before noon. High near 80. North northwest wind 8 to 14 mph becoming northeast in the morning. Winds could gust as high as 18 mph. Chance of precipitation is 90%. New precipitation amounts of less than a tenth of an inch possible.
Tonight: Showers likely. Cloudy, with a low around 69. Northeast wind 7 to 10 mph becoming northwest in the evening. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.
Friday: Showers likely, mainly before noon. Cloudy, with a high near 80. Breezy, with a north northwest wind 7 to 15 mph becoming east northeast in the afternoon. Winds could gust as high as 21 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Waikoloa
Today: Partly sunny, with a high near 85. Windy, with an east northeast wind 11 to 16 mph increasing to 18 to 23 mph in the morning. Winds could gust as high as 32 mph.
Tonight: Mostly clear, with a low around 70. Windy, with an east wind 18 to 23 mph, with gusts as high as 32 mph.
Friday: Mostly sunny, with a high near 85. Windy, with an east northeast wind 19 to 24 mph becoming light northeast in the afternoon. Winds could gust as high as 34 mph.
Detailed Forecast
Synopsis
Moderate to breezy easterly trade winds will strengthen later today through the weekend. Clouds and showers will favor windward and mauka locations, with the best chances through the overnight and early morning periods. A return of drier trade wind conditions is anticipated Friday through early next week.
Discussion
The upper trough that led to cloudy conditions over the western end of the state yesterday continues to lift northward and away from the area this morning. Plenty of middle- to upper-level dry air following it has cleared the high clouds out over Kauai and Oahu. Expect this trend to continue today with stable trade wind conditions returning. There is a large area of moisture moving into the eastern end of the state that will support decent windward and mauka shower coverage through the morning hours today. In its wake, satellite data reflects dry air farther upstream of the Big Island. Guidance has initialized well with this and has the dry air moving through from east to west tonight through Friday. This dry air combined with rising upper heights will lead to more of a suppressed and stable environment this weekend, which will limit cloud/shower windward coverage. Similar conditions will carry into next week.
Aviation
Surface high pressure north of the islands will maintain a moderate to locally strong trade wind flow through at least tonight. AIRMET Tango for low level turb, south through west of mountains, will continue through tonight as well. Scattered to broken low clouds and showers riding in with the trades upwind of the islands will result in brief MVFR ceiling and vis, favoring the windward and mountain areas. The lee side of the Big Island can expect a couple of afternoon and evening showers as well. Tops of these clouds and showers will be around 8k feet. No other AIRMETS are anticipated today.
Marine
A high pressure system far north of the region will slowly drift eastward and build from Friday into the weekend. Trade winds will strengthen from Friday onward. A Small Craft Advisory (SCA) remains in effect for the typically windy waters around Maui County and the Big Island. This SCA may be expanded in coverage over the next two days.
Surf along east facing shores will remain small through Friday, then trend up over the weekend in response to strengthening trades locally and upstream of the Hawaiian Islands.
Southerly swell activity will remain rather low for this time of the year with just background swells expected from the south and southeast. Nearly flat conditions will continue for north and west facing shores into early next week. Buoy 51001 observations are not showing any reflection of the potential small, west-northwest swell this morning, which supports the summertime conditions continuing.
HFO Watches/Warnings/Advisories
Small Craft Advisory until 6 PM HST Friday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
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Data Courtesy of NOAA.gov