Hilo

Today: Scattered showers. Partly sunny, with a high near 84. Southwest wind around 6 mph becoming east in the morning. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 64. East southeast wind around 5 mph becoming calm in the evening. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Scattered showers. Partly sunny, with a high near 81. Calm wind becoming east 5 to 8 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Kona

Today: Scattered showers after noon. Increasing clouds, with a high near 82. Calm wind becoming west northwest 5 to 7 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers before midnight. Partly cloudy, with a low around 62. North northeast wind around 6 mph becoming calm in the evening. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Scattered showers after noon. Mostly sunny, with a high near 82. Calm wind. 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. Northeast wind 11 to 14 mph, with gusts as high as 18 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 50. East 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.

Sunday: Scattered showers, mainly before noon. Mostly sunny, with a high near 76. East northeast wind 10 to 13 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kohala

Today: Scattered showers. Partly sunny, with a high near 70. Breezy, with an east wind 17 to 20 mph, with gusts as high as 28 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 40. Breezy, with an east wind 16 to 20 mph, with gusts as high as 28 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Scattered showers. Partly sunny, with a high near 69. Breezy, with an east wind 14 to 16 mph, with gusts as high as 22 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 24 to 26 mph, with gusts as high as 34 mph.

Tonight: Mostly clear, with a low around 69. Windy, with an east northeast wind around 24 mph, with gusts as high as 31 mph.

Sunday: Sunny, with a high near 83. Windy, with an east wind 21 to 24 mph, with gusts as high as 31 mph.

Puna

Today: Scattered showers. Partly sunny, with a high near 82. North northwest wind 5 to 8 mph becoming east northeast in the afternoon. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Scattered showers. Mostly cloudy, with a low around 61. North northeast wind around 8 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Scattered showers. Partly sunny, with a high near 79. East northeast wind 7 to 10 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Waikoloa

Today: Sunny, with a high near 81. East northeast wind around 9 mph becoming northwest in the afternoon.

Tonight: Clear, with a low around 60. North wind 5 to 8 mph becoming east in the evening.

Sunday: Sunny, with a high near 80. North northeast wind around 6 mph becoming calm in the afternoon.

Detailed Forecast

Synopsis

Breezy trade winds will persist through the weekend, focusing clouds and showers over windward areas. Trades will diminish early next week as an upper trough approaches from the northwest.

Discussion

Trade winds have pushed into the area as high pressure to our northeast dominates local environmental flow. Clouds and showers associated with an area of moisture have passed west of Kauai overnight, so expect drier weather as breezy trades persist for the balance of the weekend.
Models show an upper trough will amplify northwest of the islands early next week. The surface pressure gradient will weaken considerably as the associated front approaches the islands, causing winds to decrease. This is expected to muster in a land and sea breeze pattern, setting up the potential for increased afternoon showers over leeward and interior locations Monday and Tuesday.
Forecast uncertainty increases by the middle of next week concerning the development of the upper trough. GFS is on the wetter side of the solution envelope, while ECMWF shows returning trades as the upper trough shifts overhead Wednesday through Friday. This would favor a return to wetter trades of the moderate or breezy variety during the latter half of next week.

Aviation

Trade winds will become moderate to breezy across the state as a high pressure ridge north of the islands strengthens. Showers and accompanying MVFR conditions will mainly affect windward and mauka sections.
An AIRMET for mountain obscuration remains in effect for Kauai. One for low level turbulence may be needed later this morning as trade winds are on the increase.

Marine

A late season west-northwest swell that arrived yesterday afternoon over the Kauai and Oahu waters will continue to build down the island chain early this morning. The nearshore PacIOOS buoy at Waimea reflects this swell with the spectral peak centered around 16 seconds. This swell combined with fresh easterly trade wind driven energy will support seas holding near the small craft advisory threshold of 10 ft over the exposed coastal waters through Sunday. In addition to the seas, small craft advisory- level winds will continue over the channel waters between Maui County and the Big Island, Maalaea Bay, and waters around South Point through Sunday. Guidance continues to depict the ridge weakening early next week as an upper trough and front approach from the northwest. Local trades will respond and drop into the light to moderate category by Tuesday.
Surf along exposed north and west facing shores of Kauai and Oahu quickly ramped up yesterday afternoon due to the arrival of the late season west-northwest swell. Expect this source to peak early this morning, then slowly ease through Monday. A high surf advisory has been issued for north and west facing shores of Kauai and Oahu, and may near the advisory threshold for west facing shores of the Big Island today given the more westerly direction. Surf along north facing shores of Maui should remain lower due to the westerly direction and much of the energy being clipped by smaller islands to the west.
Surf along south facing shores will remain up today as a small south-southwest swell continues to move through. A downward trend is anticipated Sunday into early next week with mainly background southerly swell energy expected.
Surf along east facing shores will trend up through the weekend due to the fresh to strong trades locally and upstream. A downward trend is expected early next week as the trades weaken.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Kauai North.
Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov