Photo Credit: James Grenz

Hilo

Today: Scattered showers. Mostly sunny, with a high near 81. Calm wind becoming east northeast 5 to 9 mph 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 67. Light and variable wind. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Thursday: Scattered showers. Mostly sunny, with a high near 81. West wind 5 to 8 mph becoming east northeast in the afternoon. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Isolated showers after noon. Mostly sunny, with a high near 79. West southwest wind 5 to 7 mph becoming calm in the afternoon. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 67. Calm wind becoming east 5 to 7 mph. Chance of precipitation is 20%.

Thursday: Scattered showers after noon. Mostly sunny, with a high near 80. Calm wind becoming southwest around 6 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Waimea

Today: Scattered showers, mainly after noon. Mostly sunny, with a high near 76. Breezy, with a northeast wind 8 to 18 mph, with gusts as high as 26 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers, mainly after midnight. Partly cloudy, with a low around 57. East wind around 8 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Thursday: Scattered showers. Mostly sunny, with a high near 76. East northeast wind 6 to 8 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Kohala

Today: Scattered showers. Mostly sunny, with a high near 69. East wind 9 to 14 mph, with gusts as high as 20 mph. 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 56. East wind 9 to 11 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Thursday: Scattered showers. Mostly sunny, with a high near 69. East wind 7 to 9 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Sunny, with a high near 83. Windy, with an east wind 18 to 23 mph, with gusts as high as 29 mph.

Tonight: Partly cloudy, with a low around 73. Breezy, with an east northeast wind 14 to 18 mph, with gusts as high as 23 mph.

Thursday: Isolated showers after noon. Mostly sunny, with a high near 83. Breezy, with an east wind 14 to 17 mph, with gusts as high as 21 mph. Chance of precipitation is 20%.

Puna

Today: Scattered showers. Partly sunny, with a high near 78. Northwest wind 7 to 14 mph becoming northeast in the afternoon. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely, mainly after midnight. Mostly cloudy, with a low around 64. North wind around 9 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

Thursday: Scattered showers. Partly sunny, with a high near 77. North northeast wind 7 to 10 mph. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Waikoloa

Today: Sunny, with a high near 84. Breezy, with an east northeast wind 9 to 16 mph becoming northwest in the afternoon. Winds could gust as high as 23 mph.

Tonight: Partly cloudy, with a low around 66. Northeast wind 3 to 5 mph.

Thursday: Isolated showers after 1pm. Sunny, with a high near 83. North northeast wind 3 to 5 mph. Chance of precipitation is 20%.

Detailed Forecast

Synopsis

Trade winds will decrease beginning today, leading to less windward rainfall. By Friday and Saturday, local land and sea breezes will create a pattern of afternoon clouds and showers over interior and leeward areas, followed by night time clearing. Trade winds will ramp back up by Sunday, reaching breezy levels once again through early next week.

Discussion

The subtropical ridge far north of the main Hawaiian Islands keeps the pressure gradient steep enough to support moderate trade winds across local waters this morning. Satellite loop shows areas of broken low clouds moving across windward and mauka portions of the islands, while radar shows scattered showers within these clouds. Overnight soundings show a strong inversion near 6800 feet, which caps deep convection and limits total rainfall. Expect the current pattern to continue for the next few days, with scattered showers riding in on the trades, focusing over windward areas.
Troughing expected to develop north and northeast of the islands beginning today will put a dent in the subtropical ridge, causing the pressure gradient across the islands to slacken. Trades will gradually weaken beginning later today, becoming light to moderate by Thursday and Friday. Winds will gradually veer toward the east and become east-southeast on Friday. Afternoon sea breezes will likely develop across select leeward areas and we should see clouds and showers develop over interior and leeward areas on Friday afternoon and possibly Saturday afternoon as well. Trades will begin filling in from east to west late Saturday and we should see breezy conditions across the state by Sunday. Scattered showers will once again be focused over windward areas and we should continue to see this pattern through early next week.

Aviation

The trade winds have diminished into the light to moderate range, and will remain at this range for the next couple of days. Therefore, AIRMET Tango has been lowered.
Satellite imagery shows large patches of low cloud with embedded showers pushing through the islands from the east. Persistent showers have lead to an AIRMET Sierra for mountain obscuration on Oahu. The windward side of the remaining islands are being threatened with an AIRMET Sierra as well. The frequency of these showers will be becoming less through this morning. We are anticipating Sierra to be canceled by 20z. Tops of these clouds are between 8k and 10k feet.
In the afternoon, the slightly lighter trades will lead to local sea breezes, which in turn result in some clouds and showers over the far western end of some islands such as Kauai and Oahu, and to especially the lee side of the Big Island.

Marine

Moderate to locally breezy trade winds will gradually ease over the next few days as high pressure north of the islands weakens. As the winds have lessened sufficiently this early morning, the Small Craft Advisory (SCA) has been cancelled for the typically windy waters around Maui County and the Big Island. However, high pressure will rebuild during the weekend, leading to increased trade winds and SCA conditions once again.
A High Surf Advisory continues for south facing shores through this afternoon. However, south shore surf has been fading and will continue to decline through Friday, and drop to background levels during the weekend.
East shore surf will subside over the next few days as trade winds weaken across the region. The short-period energy will steadily decrease today and Thursday, then rebuild to near average late Saturday and Sunday as trade winds strengthen. A tiny northwest swell will decline, leading to a return to nearly flat north shore conditions later today.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai Southeast, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, Kipahulu, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.

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Data Courtesy of NOAA.gov