Weather Forecast

Hawaii County Weather Forecast for July 20, 2021

July 20, 2021, 7:16 AM HST
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Hilo

Today: Showers likely. Mostly cloudy, with a high near 80. North wind 5 to 10 mph becoming east northeast in the afternoon. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Occasional showers. Low around 68. Northeast wind around 6 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Wednesday: Occasional showers, mainly before 1pm. High near 81. East northeast wind around 8 mph. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Isolated showers after noon. Increasing clouds, with a high near 80. Light and variable wind becoming west northwest 5 to 8 mph in the morning. Chance of precipitation is 20%.

Tonight: Scattered showers, mainly before midnight. Mostly cloudy, with a low around 68. South wind around 6 mph becoming northwest in the evening. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

ARTICLE CONTINUES BELOW AD

Wednesday: Isolated showers after noon. Increasing clouds, with a high near 81. West wind around 5 mph becoming calm in the morning. Chance of precipitation is 20%.

Waimea

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Today: Scattered showers. Partly sunny, with a high near 75. Breezy, with an east northeast wind 18 to 20 mph, with gusts as high as 28 mph. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 59. Breezy, with an east wind around 16 mph, with gusts as high as 22 mph. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 75. East northeast wind around 14 mph, with gusts as high as 18 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Kohala

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Today: Showers likely. Mostly cloudy, with a high near 68. Windy, with an east wind 23 to 28 mph, with gusts as high as 40 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 58. Windy, with an east wind 17 to 23 mph, with gusts as high as 32 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

Wednesday: Showers likely. Mostly cloudy, with a high near 69. Windy, with an east northeast wind 17 to 23 mph, with gusts as high as 32 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Isolated showers before noon. Mostly sunny, with a high near 84. Windy, with an east wind 22 to 28 mph, with gusts as high as 36 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 74. Windy, with an east northeast wind 21 to 23 mph, with gusts as high as 29 mph. Chance of precipitation is 20%.

Wednesday: Isolated showers before noon. Mostly sunny, with a high near 85. Windy, with an east wind 20 to 24 mph, with gusts as high as 31 mph. Chance of precipitation is 20%.

Puna

Today: Showers likely. Mostly cloudy, with a high near 77. Breezy, with a northeast wind 11 to 15 mph, with gusts as high as 21 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Occasional showers. Low around 66. North northeast wind 9 to 13 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Wednesday: Showers likely, mainly before noon. Mostly cloudy, with a high near 77. Northeast wind around 14 mph, with gusts as high as 18 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

Waikoloa

Today: Sunny, with a high near 83. Breezy, with a northeast wind 8 to 15 mph, with gusts as high as 21 mph.

Tonight: Mostly clear, with a low around 68. Northeast wind around 9 mph.

Wednesday: Sunny, with a high near 83. North northeast wind 6 to 8 mph.

Detailed Forecast

Synopsis

Breezy and locally gusty trade winds will continue through the week, with showers primarily focused over windward and mauka areas, especially during the overnight and early morning hours. More widespread showers are possible over the weekend.

Discussion

Breezy and locally gusty trade winds will persist through the week, occasionally delivering clouds and showers that will primarily dampen windward areas. A few light sprinkles spreading leeward will do little to help the parched landscape.
Strong high pressure far N of the islands will change little today, then gradually drift W over the next several days. Locally strong trade winds will continue in the short term, then ease slightly the next day or two. Confidence is high that most of the increased moisture from the remnants of Felicia will pass S of the islands toward the end of the week, but some peripheral moisture may increase trade showers Thursday into Friday. The resulting tightening pressure gradient may lead to trade wind speeds increasing slightly. A more significant slug of low-level moisture, associated with the remnants of Guillermo, may be near the islands late next weekend. An associated surface trough may lead to weaker winds as it loosens the local gradient.

Aviation

Locally windy trade winds will continue today due to strong surface high pressure far north and northwest of the state. A large area of broken to locally overcast low clouds with embedded scattered showers is being transported into the eastern Big Island this morning. This will likely result in periods of MVFR conditions over the slopes and coastal sections of the windward Big Island today. There are also low clouds and showers over most of the windward sections of the smaller islands. Expect brief periods of MVFR conditions over north through east sections of some of the smaller islands through mid-morning.
AIRMET Tango for TEMPO moderate turbulence over and south through west of the higher terrain on all islands will likely remain in effect through tonight. AIRMET Sierra for mountain obscuration is in effect for the windward sides of most islands. This AIRMET may be dropped for some of the smaller islands later this morning, but may remain in effect for the Big Island until mid-day.

Marine

A strong high pressure ridge north of the Hawaiian Islands will continue to produce fresh to strong trade winds and elevated rough seas through the week. A Small Craft Advisory (SCA) was extended in time to include all coastal waters through this afternoon, and for the windier channels and waters over the eastern half of the state through Thursday morning.
Surf along east facing shores will remain elevated with choppy conditions into the weekend due to the strong trades. Select areas on the south and north shores should see some localized increases in surf due to trade wind swell wrap.
Tropical Cyclone Felicia, currently in the Eastern Pacific, will drift west and weaken over the next two days. The remnants of this system will pass south of the Hawaiian Islands this weekend. Trade winds will increase a bit as remnants of Felicia pass south of the state, with a slight increase in trade wind swell and surf heights expected for east facing shores.
No swell from west or north directions are expected over the next seven days, thus surf heights for north and west facing shores will remain nearly flat.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Thursday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.
Small Craft Advisory until 6 PM HST this evening for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Big Island Windward Waters.

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Data Courtesy of NOAA.gov

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