Hilo

Today: Showers likely, mainly before noon. Mostly cloudy, with a high near 79. North northeast wind 6 to 9 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 64. North northeast wind 5 to 8 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 78. North northeast wind 5 to 8 mph. Chance of precipitation is 50%. 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. Calm wind becoming west around 5 mph in the morning. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Mostly cloudy, then gradually becoming mostly clear, with a low around 62. Calm wind. Chance of precipitation is 20%.

Wednesday: Scattered showers after noon. Increasing clouds, with a high near 79. Light and variable wind. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Waimea

Today: Scattered showers, mainly before noon. Mostly sunny, with a high near 76. Breezy, with an east northeast wind 18 to 21 mph, with gusts as high as 29 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 53. Breezy, with an east northeast wind 16 to 20 mph, with gusts as high as 28 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers, mainly before noon. Mostly sunny, with a high near 75. Breezy, with an east northeast wind 16 to 18 mph, with gusts as high as 25 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kohala

Today: Showers likely. Mostly cloudy, with a high near 72. Breezy, with an east northeast wind 18 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 46. Breezy, with an east northeast wind around 17 mph, with gusts as high as 24 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Showers likely, mainly after noon. Mostly cloudy, with a high near 71. Breezy, with an east northeast wind 16 to 18 mph, with gusts as high as 25 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

South Big Island

Today: Sunny, with a high near 75. Windy, with an east northeast wind around 25 mph, with gusts as high as 32 mph.

Tonight: Mostly clear, with a low around 68. Windy, with an east northeast wind around 23 mph, with gusts as high as 30 mph.

Wednesday: Sunny, with a high near 74. Windy, with an east northeast wind around 23 mph, with gusts as high as 30 mph.

Puna

Today: Occasional showers. High near 76. North northeast wind 11 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 62. North northeast wind 10 to 13 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 75. North northeast wind around 11 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 82. Breezy, with an east northeast wind 18 to 22 mph, with gusts as high as 31 mph.

Tonight: Mostly clear, with a low around 62. Breezy, with an east northeast wind 16 to 21 mph, with gusts as high as 29 mph.

Wednesday: Sunny, with a high near 81. Breezy, with an east northeast wind 16 to 18 mph, with gusts as high as 25 mph.

Detailed Forecast

Synopsis

Breezy trade winds will persist into Wednesday as strong high pressure holds far north of the state. Showers will favor windward shores and slopes. Trade winds will decrease late Wednesday and remain at moderate strength through Friday, leading to typical trade wind weather. Trades may diminish this weekend.

Discussion

Breezy trade winds persist, and wet conditions continue over windward portions of the islands this morning. A band of moisture remains hung up on windward Maui County and the Big Island, but additional moisture has spread to the other islands overnight. Trade winds will remain locally breezy today and perhaps into Wednesday. Showers will focus across windward terrain as shallow pockets of moisture move along within trade wind flow.
Trade winds will decrease bay late Wednesday. A high to the north of the islands will weaken and a low far northeast of the state will drift westward. Trades will remain at moderate strength through Friday. Models show a slow moving upper trough just east of the state and an upper ridge to the west, keeping the islands within stable trade wind flow.
There is some uncertainty in the weekend forecast. Models show the low dissipating at the surface, and remnant moisture moving over the islands in a weakening trade wind flow. However, ECMWF shows the nearby upper trough deepening and possibly moving over the islands, while GFS is keeping this feature a little farther east. Heavy rainfall is possible, but it is too far out to tell at this time.

Aviation

A nearly stationary 1040 mb surface high located far north of the islands will maintain breezy trade winds across the area through at least tonight. Hence, AIRMET Tango, for low level turbulence will continue through at least 071000 utc.
Remnants of an old front remains hung up over the windward slopes of Molokai, Maui and the Big Island, where AIRMET Sierra for mountain obscuration is in effect. Surface observations from windward sites of these islands indicate that the ceilings have lifted to above 3k feet. This usually means VFR, but persistent rain will keep the AIRMET going until further notice. A new shower area with widely scattered showers is pushing through the islands now. So any improvements to windward areas of Molokai, Maui, and the Big Island, will come later this morning. Do expect a few of these passing showers to reach well into the leeward sections of the smaller islands this morning. In the afternoon, a few showers is possible over the lee side of the Big Island.

Marine

High pressure north of the islands will keep fresh to strong trades in place through Wednesday. The trades will trend down Thursday as the high north of the state weakens, with light to moderate trades expected Friday through the weekend. A Small Craft Advisory (SCA) is now in effect for all waters through 6 AM Wednesday. The SCA will likely need to be extended for some marine zones through Thursday and possibly Thursday night, while other waters gradually fall below SCA thresholds.
The current north-northeast swell will hold fairly steady through Wednesday, then slowly decline Thursday through the weekend. This will keep surf along north and east facing shores elevated through the work week, before surf drops to near or slightly below normal levels this weekend. A High Surf Advisory remains is now in effect for east facing shores through 6 PM Thursday, and may need to be extended through Thursday night and possibly Friday. This swell may also produce surges in north facing harbors such as Kahului and Hilo.
South shore surf will remain small through the work week, with mainly background south swells moving through. A larger long- period south swell is expected to give surf a boost over the weekend into early next week.

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.
Small Craft Advisory until 6 AM HST Wednesday for all Hawaiian waters.

Data Courtesy of NOAA.gov