Photo Credit: Tyler Rooke

West Side

Today: Isolated showers. Partly sunny, with a high near 82. Very windy, with an east northeast wind 22 to 31 mph, with gusts as high as 45 mph. Chance of precipitation is 20%.

Tonight: Scattered showers, mainly after 7pm. Mostly cloudy, with a low around 67. Windy, with an east northeast wind around 25 mph, with gusts as high as 36 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Scattered showers before noon. Mostly sunny, with a high near 83. Windy, with an east northeast wind 18 to 25 mph, with gusts as high as 29 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

South Side

Today: Scattered showers after noon. Mostly sunny, with a high near 82. Windy, with an east northeast wind 10 to 15 mph increasing to 18 to 23 mph in the afternoon. Winds could gust as high as 32 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers. Partly cloudy, with a low around 65. Windy, with a northeast wind around 23 mph, with gusts as high as 32 mph. Chance of precipitation is 20%.

Sunday: Scattered showers, mainly after 11am. Partly sunny, with a high near 83. Breezy, with an east northeast wind 10 to 16 mph, with gusts as high as 23 mph. Chance of precipitation is 30%. New precipitation amounts between a tenth and quarter of an inch possible.

North Shore

Today: Scattered showers, mainly before 1pm. Partly sunny, with a high near 80. Very windy, with a northeast wind 17 to 22 mph increasing to 27 to 32 mph in the morning. Winds could gust as high as 47 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 66. Windy, with a north northeast wind 28 to 30 mph, with gusts as high as 44 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Scattered showers, mainly before noon. Partly sunny, with a high near 81. Windy, with an east wind 22 to 30 mph, with gusts as high as 34 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Central Maui

Today: Scattered showers, mainly before noon. Partly sunny, with a high near 80. Very windy, with a northeast wind 17 to 22 mph increasing to 27 to 32 mph in the morning. Winds could gust as high as 47 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 64. Windy, with a northeast wind around 29 mph, with gusts as high as 41 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Scattered showers, mainly before 11am. Mostly sunny, with a high near 81. Windy, with a northeast wind 16 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.

Upcountry

Today: Isolated showers after noon. Mostly sunny, with a high near 67. Breezy, with a northeast wind 7 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 53. Breezy, with an east wind around 17 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.

Sunday: Isolated showers. Mostly sunny, with a high near 68. Breezy, with an east northeast wind 10 to 18 mph, with gusts as high as 26 mph. Chance of precipitation is 20%.

East Maui

Today: Showers. High near 78. Windy, with a northeast wind 15 to 24 mph, with gusts as high as 34 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.

Tonight: Frequent showers. Low around 62. Breezy, with an east wind around 20 mph, with gusts as high as 28 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.

Sunday: Frequent showers, mainly before noon. High near 79. Breezy, with an east wind 16 to 20 mph, with gusts as high as 25 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.

Lanai City

Today: Scattered showers after noon. Mostly sunny, with a high near 73. Very windy, with an east northeast wind 25 to 32 mph, with gusts as high as 47 mph. Chance of precipitation is 30%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Isolated showers. Partly cloudy, with a low around 62. Windy, with an east northeast wind around 30 mph, with gusts as high as 44 mph. Chance of precipitation is 20%.

Sunday: Scattered showers, mainly after 11am. Mostly sunny, with a high near 74. Breezy, with an east northeast wind 18 to 22 mph, with gusts as high as 32 mph. Chance of precipitation is 30%. New precipitation amounts between a tenth and quarter of an inch possible.

Kaunakakai

Today: Isolated showers. Mostly sunny, with a high near 79. Windy, with an east northeast wind 18 to 28 mph, with gusts as high as 40 mph. Chance of precipitation is 20%.

Tonight: Scattered showers, mainly after 7pm. Mostly cloudy, with a low around 69. Windy, with an east northeast wind 25 to 28 mph, with gusts as high as 40 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Sunday: Scattered showers before noon. Mostly sunny, with a high near 79. Windy, with an east northeast wind 22 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.

Detailed Forecast

Synopsis

Showery conditions will remain in place for windward and mountain locations through tonight due to a band of moisture drifting southward into the area and an upper disturbance. Northeast trade winds will reach advisory levels through this time while gradually becoming more easterly by Sunday. Winds will ease through the day Monday, then shift out of the south Monday night through midweek as a cold front and upper disturbance approach and move into the area. The potential for another round of wet conditions will increase Tuesday through midweek, especially over the western end of the state where the front could stall.

Discussion

Satellite imagery showed a band of low clouds drifting southward into the area this morning, which supports increasing shower coverage for windward and mountain locations through tonight. Some of these showers will occasionally carry over into leeward sections – best chances being through the early morning periods. In addition to the showery conditions, lowering upper heights associated with the upper trough could trigger a few thunderstorms over the eastern end of the state as the trough sharpens and potentially closes off into an upper low.
Northeast trade winds are expected to reach advisory levels today due to this band of moisture moving in and strong high pressure passing to the north. A Wind Advisory has been posted for most of the state (with the exception of a few areas on Maui and the Big Island that are normally not exposed to the trade wind flow) that continues through tonight. Saturated soils from recent rainfall combined with wind gusts potentially reaching 45 mph in exposed areas could down trees and large branches. Strongest winds will be felt near mountain tops and passes, trade wind exposed areas and around incoming showers.
Drier weather is expected later Sunday with breezy trades holding. A cold front will approach the islands and begin to weaken the trade winds further on Monday. Background winds will veer southerly and become light and variable for many areas around the state Monday night into Tuesday. The front will arrive Tuesday night or Wednesday on Kauai and then stall somewhere over the smaller islands Wednesday and Thursday. Showers will increase along and ahead of the boundary as early as Tuesday across the state, with Wednesday and Thursday likely being the wettest days. Model solutions begin to diverge late next week, which reduces forecast confidence.

Aviation

A high pressure system passing north of the state will produce breezy to windy trade winds lasting through Sunday. An upper level trough over the region will continue to enhance shower activity across the area. Unstable cloud bands are moving into the islands from the east this morning, with deeper moisture moving into the Big Island from the southeast direction.
Expect periods of MVFR conditions through the early morning hours along north and east facing slopes of some islands with unstable showers driven up the mountain slopes by strong trade winds. Isolated thunderstorms remain in the forecast over the eastern end of the state this afternoon.
AIRMET Sierra remains in effect for Mountain Obscurations over the north and east slopes of Kauai and the Big Island. This AIRMET may expand today to cover additional islands.
AIRMET Tango remains in effect for low level Moderate Turbulence over and south through west of all island mountains due to strong trade winds. This AIRMET will remain in effect at least through Sunday. AIRMET Tango for strong surface winds greater than 30 knots was also issued this morning.

Marine

High pressure north of the state moving east into the East Pacific will maintain a tight enough pressure gradient back across the Hawaiian Island waters to produce fresh to strong trade winds this weekend. A north northeast swell, along with strong trades, will have an all water Small Craft Advisory (SCA) in effect through Sunday. The lone exception to the SCA will be in the Alenuihaha Channel where a Gale Warning (GLW) is in effect through tonight. This enhanced trade wind and north northeast swell tandem will also support the High Surf Advisory (HSA) for exposed east-facing shoreline surf through Sunday. Eastern Pacific high pressure will be pushed farther east as a cold front approaches the state from the northwest early next week. The result will be weakened winds that will veer more southerly ahead of the front Monday night. Winds are forecast to weaken late Sunday through Monday and will likely fall below SCA criteria Monday.
The next appreciable northwest swell is scheduled to pass around the islands Wednesday and Thursday. This moderate height, lower period northwest swell may push surf along north and west-facing shores to HSA levels Wednesday and Thursday. Periodic small, long period southwest to south swells emanating from gales south of New Zealand will produce a modest boost to mid week south-facing shore surf.

HFO Watches/Warnings/Advisories

Wind Advisory until 6 AM HST Sunday for Niihau, Kauai, Oahu, Molokai, Lanai, Kahoolawe, Maui Windward West, Maui Leeward West, Maui Central Valley, Windward Haleakala, Leeward Haleakala, South Big Island, Big Island North and East, Kohala.
High Surf Advisory until 6 PM HST Sunday for Kauai Windward, Oahu Koolau, Olomana, Molokai Windward, Maui Windward West, Windward Haleakala, Big Island North and East.
Small Craft Advisory until 6 PM HST Sunday 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, Maalaea Bay, Pailolo Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.
Gale Warning until 6 AM HST Sunday for Alenuihaha Channel.

Data Courtesy of NOAA.gov