Photo Credit: Tyler Rooke

West Side

Today: Scattered showers, mainly after noon. Mostly sunny, with a high near 84. Light and variable wind becoming south 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: Showers likely, mainly after midnight. Mostly cloudy, with a low around 66. South southeast wind around 9 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Showers likely, mainly before noon. Partly sunny, with a high near 83. South wind around 10 mph. Chance of precipitation is 60%. 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 83. Light and variable wind becoming south around 6 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 63. South southeast wind 5 to 7 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Wednesday: Showers likely, mainly before noon. Partly sunny, with a high near 83. South wind 6 to 13 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch possible.

North Shore

Today: Isolated showers. Mostly sunny, with a high near 81. Light and variable wind. Chance of precipitation is 20%.

Tonight: Scattered showers. Mostly cloudy, with a low around 64. Southeast wind 3 to 6 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 81. Light and variable wind becoming southwest around 5 mph in the afternoon. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Central Maui

Today: Isolated showers after noon. Mostly sunny, with a high near 81. Light north wind. Chance of precipitation is 20%.

Tonight: Scattered showers. Mostly cloudy, with a low around 63. South wind 3 to 6 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Showers likely, mainly before noon. Partly sunny, with a high near 81. South wind 5 to 8 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Upcountry

Today: Scattered showers after noon. Mostly sunny, with a high near 68. West wind 3 to 7 mph. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Scattered showers, mainly after midnight. Partly cloudy, with a low around 52. Light southeast wind becoming south 8 to 13 mph after midnight. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Wednesday: Scattered showers. Partly sunny, with a high near 67. South southwest wind 7 to 11 mph. Chance of precipitation is 50%. New precipitation amounts between a quarter and half of an inch possible.

East Maui

Today: Scattered showers. Partly sunny, with a high near 79. Breezy, with a southeast wind 10 to 15 mph, with gusts as high as 21 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 60. Southeast wind 9 to 14 mph becoming light after midnight. Winds could gust as high as 18 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Isolated showers. Mostly sunny, with a high near 79. Southeast wind 6 to 8 mph. Chance of precipitation is 20%.

Lanai City

Today: Scattered showers, mainly after noon. Mostly sunny, with a high near 75. Light and variable wind becoming south 5 to 7 mph in the afternoon. Chance of precipitation is 50%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Occasional showers. Low around 64. Breezy, with a south wind 15 to 18 mph, with gusts as high as 25 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.

Wednesday: Occasional showers, mainly before noon. High near 75. Breezy, with a south wind around 20 mph, with gusts as high as 28 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.

Kaunakakai

Today: Scattered showers, mainly after noon. Mostly sunny, with a high near 80. South wind 3 to 5 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 66. South southeast wind 9 to 11 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Wednesday: Showers likely. Mostly cloudy, with a high near 80. South southeast wind 11 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Detailed Forecast

Update

Have updated the forecast for Oahu to better reflect some convergence already occuring ahead of the front that is bringing some showers to the south shore of Oahu this morning.

Synopsis

Winds have weakened and turned southerly ahead of an approaching cold front. Rainfall chances will increase this afternoon and tonight as showers move up over the islands from the south. Rainfall chances will remain elevated into Thursday over the central islands, and then shift to Kauai Friday as trade winds push in from the east.

Aviation

Winds will be light today, veering to southeasterlies and southerlies as a front approaches from the northwest. Clouds and showers will increase across mauka areas this afternoon. Brief MVFR conditions are possible, though VFR conditions should prevail. Thunderstorms are possible over interior Big Island slopes this afternoon.
No AIRMETS are in effect this morning and none are expected today.

Marine

A front approaching from the northwest has been entering the offshore waters this morning, and will shift winds out ahead of the boundary to a southerly direction. The front is expected to reach the northwest coastal waters Wednesday, and stall over the central waters by Thursday.
As the high far northeast of the area continues to move away and with trades weakening, surf along east facing shores is on the decline. However, a new northwest swell is expected to begin arriving tonight, and will boost surf along north and west facing shores, with surf nearing advisory levels during the peak of the event Wednesday night through Thursday. This swell is then expected to decline Friday and Saturday.
Some small long period south swells will continue to boost surf along south facing shores through the week.

Prev discussion

/ISSUED 358 AM HST Tue Mar 23 2021/
A cold front off to the northwest of the islands will push toward Kauai today veering islands winds from the south. Convergence in the low level wind flow will produce increasing showers this afternoon, mainly over Oahu and Maui County, and continue into the end of the week as the front stalls near Kauai Wednesday night. Upper level support will be weak at best through Thursday but a stray thunderstorm within a stronger convergence cell may be possible. This scenario will likely bring partly cloudy skies and bands of showers that could produce nuisance flooding through the week. If one of these bands remains stationary over an area for an extended time period than there is a chance of localized flash flooding. However, without strong upper level support, widespread flash flooding is not likely at this time.
Friday, high pressure to the northeast is expected to build in trade winds from east to west across the state. Current model solutions place a remnant trough near Oahu Thursday night that will push westward with the trades Friday. This scenario would bring increasing showers to Kauai, while the rest of the state transitions to a trade wind regime.
AVIATION… Winds will be light today, veering to southeasterlies and southerlies as a front approaches from the northwest. Clouds and showers will increase across mauka areas this afternoon. Brief MVFR conditions are possible, though VFR conditions should prevail. Thunderstorms are possible over interior Big Island slopes this afternoon.
No AIRMETS are in effect this morning and none are expected today.
MARINE… A front approaching from the northwest has been entering the offshore waters this morning, and will shift winds out ahead of the boundary to a southerly direction. The front is expected to reach the northwest coastal waters Wednesday, and stall over the central waters by Thursday.
As the high far northeast of the area continues to move away and with trades weakening, surf along east facing shores is on the decline. However, a new northwest swell is expected to begin arriving tonight, and will boost surf along north and west facing shores, with surf nearing advisory levels during the peak of the event Wednesday night through Thursday. This swell is then expected to decline Friday and Saturday.
Some small long period south swells will continue to boost surf along south facing shores through the week.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov