West Side

This Afternoon: Isolated showers. Mostly sunny, with a high near 88. East wind around 10 mph. Chance of precipitation is 20%.

Tonight: Isolated showers before 9pm. Partly cloudy, with a low around 71. East northeast wind 9 to 11 mph. Chance of precipitation is 20%.

Monday: Mostly sunny, with a high near 88. East northeast wind 10 to 13 mph.

South Side

This Afternoon: Mostly sunny, with a high near 82. West wind 8 to 13 mph becoming light.

Tonight: Partly cloudy, with a low around 67. Calm wind.

Monday: Mostly sunny, with a high near 83. Calm wind becoming west southwest around 6 mph.

North Shore

This Afternoon: Scattered showers. Partly sunny, with a high near 84. Breezy, with an east wind around 21 mph, with gusts as high as 29 mph. Chance of precipitation is 30%.

Tonight: Scattered showers. Mostly cloudy, with a low around 70. Breezy, with an east wind 16 to 18 mph, with gusts as high as 25 mph. Chance of precipitation is 30%.

Monday: Scattered showers, mainly before 7am. Mostly sunny, with a high near 83. Breezy, with an east wind 16 to 20 mph, with gusts as high as 28 mph. Chance of precipitation is 30%.

Central Maui

This Afternoon: Isolated showers. Mostly sunny, with a high near 84. Breezy, with an east northeast wind 16 to 20 mph, with gusts as high as 28 mph. Chance of precipitation is 20%.

Tonight: Isolated showers before 9pm. Partly cloudy, with a low around 70. Breezy, with a northeast wind 9 to 15 mph, with gusts as high as 21 mph. Chance of precipitation is 20%.

Monday: Isolated showers after 2pm. Mostly sunny, with a high near 84. Breezy, with a northeast wind 9 to 17 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.

Upcountry

This Afternoon: Mostly sunny, with a high near 71. West wind 6 to 11 mph.

Tonight: Partly cloudy, with a low around 55. Light and variable wind.

Monday: Mostly sunny, with a high near 71. Calm wind becoming west around 5 mph in the afternoon.

East Maui

This Afternoon: Showers likely. Mostly cloudy, with a high near 78. East wind around 9 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Showers likely. Mostly cloudy, with a low around 71. East wind 5 to 9 mph. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

Monday: Showers likely, mainly before 1pm. Mostly cloudy, with a high near 78. East wind 5 to 9 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

Lanai City

This Afternoon: Scattered showers. Partly sunny, with a high near 76. Breezy, with a northeast wind 13 to 15 mph, with gusts as high as 21 mph. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

Tonight: Scattered showers before 9pm. Partly cloudy, with a low around 65. Northeast wind 10 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Monday: Isolated showers after 2pm. Mostly sunny, with a high near 76. Northeast wind 10 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 20%.

Kaunakakai

This Afternoon: Mostly sunny, with a high near 88. Breezy, with an east wind 13 to 18 mph, with gusts as high as 25 mph.

Tonight: Partly cloudy, with a low around 73. East northeast wind 9 to 13 mph.

Monday: Mostly sunny, with a high near 87. East wind 9 to 11 mph.

Detailed Forecast

Synopsis

Breezy trade winds and showers will gradually ease through Monday. Winds and showers will diminish further Monday night, with light winds and mostly dry weather prevailing from Tuesday through Wednesday night. Northeast winds will pick up Thursday and become strong Thursday night and Christmas Day. The strong trade winds may be accompanied by increasing showers.

Discussion

A ridge of high pressure far north of the state will gradually shift south and approach the state over the next few days. This will cause the trade winds to slowly diminish over the next few days with winds becoming light and variable on Wednesday. The light winds will be short-lived as high pressure builds far north of the state towards the end of the week. Strong northeasterly trade winds are expected by the end of the week.
As far as precipitation, passing showers will continue to ride in with the trades with the most frequent showers expected over the windward Big Island. This has been the story over the past several days, with windward Big Island receiving over 10 inches of rain over the past 72 hours for select areas. Where as the western end of the state has only seen 1 to 3 inches of rain for the highest locations during the past 72 hours. This trend will continue through Monday, but rainfall amounts should be on the decrease on Tuesday. As the ridge shifts close to the state on Wednesday, this will bring much drier weather with only a few light afternoon showers. In the long range, models are hinting at a front moving through the state towards the end of the week. This could bring another round of wet weather.

Aviation

High pressure far northeast of Hawaii will drive fresh trade winds across the area into Monday. AIRMET Tango is posted for tempo moderate turbulence below 100 south through west of mountains. Winds will likely weaken Monday night as a front moves into the location of the high.
The trade winds are pushing low clouds and light to moderate showers over windward slopes of all exposed islands. AIRMET Sierra is posted for tempo mountain obscurations over above 025 due to these incoming clouds and showers, which will likely continue through tonight.

Marine

With high pressure weakening far northeast of the islands, winds will be easing over the next few days. However, locally strong trades in the typically windy zones around Maui County and the Big Island warrant continuation of the Small Craft Advisory, which is now in effect through Monday afternoon.
A new west to northwest swell has been tentatively arriving in the coastal waters. Peak surf heights associated with this swell will remain below advisory levels. A larger, slightly longer- period, west-northwest swell is possible around the middle of the week. If this latter swell comes in as anticipated, a High Surf Advisory (HSA) is likely.
With trade winds beginning to decrease, east shore surf is lowering as well. Out-of-season southerly swells are expected to give south shore surf a small bump through early next week. Lastly, northeast trades are expected to become strong and gusty late this week, so east shore surf will again build accordingly.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov