Photo Credit: Tyler Rooke

West Side

Today: Sunny, with a high near 85. North wind 3 to 5 mph.

Tonight: Mostly clear, with a low around 65. Light and variable wind.

Tuesday: Isolated showers after 1pm. Widespread haze after 7am. Sunny, with a high near 84. Light east northeast wind. Chance of precipitation is 20%.

South Side

Today: Isolated showers after noon. Mostly sunny, with a high near 85. East wind 8 to 10 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 63. East wind 8 to 10 mph. Chance of precipitation is 20%.

Tuesday: Scattered showers after noon. Widespread haze. Mostly sunny, with a high near 84. East wind around 9 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

North Shore

Today: Isolated showers before 1pm. Sunny, with a high near 83. East wind around 11 mph. Chance of precipitation is 20%.

Tonight: Isolated showers after 1am. Partly cloudy, with a low around 64. East southeast wind 7 to 10 mph. Chance of precipitation is 20%.

Tuesday: Isolated showers. Widespread haze after 7am. Mostly sunny, with a high near 82. East wind 10 to 13 mph. Chance of precipitation is 20%.

Central Maui

Today: Sunny, with a high near 83. East wind around 7 mph.

Tonight: Isolated showers after midnight. Partly cloudy, with a low around 62. East wind 3 to 7 mph. Chance of precipitation is 20%.

Tuesday: Isolated showers. Widespread haze. Mostly sunny, with a high near 82. East wind 7 to 10 mph. Chance of precipitation is 20%.

Upcountry

Today: Sunny, with a high near 70. East wind 8 to 11 mph.

Tonight: Mostly clear, with a low around 53. East wind around 10 mph.

Tuesday: Isolated showers after noon. Widespread haze. Mostly sunny, with a high near 70. East wind 8 to 10 mph. Chance of precipitation is 20%.

East Maui

Today: Scattered showers, mainly before noon. Mostly sunny, with a high near 81. East southeast wind 10 to 14 mph, with gusts as high as 18 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 60. Breezy, with an east southeast wind 10 to 15 mph, with gusts as high as 21 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tuesday: Scattered showers. Widespread haze. Partly sunny, with a high near 80. Breezy, with an east southeast wind 15 to 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.

Lanai City

Today: Scattered showers after noon. Increasing clouds, with a high near 76. East northeast wind 5 to 9 mph becoming north northwest in the morning. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 62. North wind around 5 mph becoming calm after midnight. Chance of precipitation is 20%.

Tuesday: Scattered showers after noon. Widespread haze. Partly sunny, with a high near 76. Calm wind becoming southwest 5 to 9 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Kaunakakai

Today: Sunny, with a high near 82. Calm wind becoming northwest 5 to 7 mph.

Tonight: Mostly clear, with a low around 67. Light and variable wind becoming southeast around 5 mph.

Tuesday: Widespread haze. Mostly sunny, with a high near 81. Light and variable wind becoming west 6 to 11 mph in the afternoon.

Detailed Forecast

Synopsis

A passing cold front north of the state will weaken the high pressure ridge over the region for the next few days. Light to moderate east to southeasterly winds will prevail through Wednesday. These lighter large scale southeasterly winds will allow local scale land and sea breezes to develop through the middle of the week. Cloud and isolated to scattered shower patterns will trend towards afternoons over island mountain and interior sections. The eastern and southeastern slopes of the Big Island will also see brief periods of rainfall. A passing high pressure system on New Years Eve will bring moderate to breezy trade winds back to the region, just in time for the New Years Eve celebrations. Breezy trade winds with brief passing showers over windward areas are forecast to continue through the weekend.

Discussion

This mornings satellite imagery continues to show fairly stable trends with cloud bands moving towards the northwest direction in a light to moderate east to southeasterly wind flow pattern. A slow moving cold front roughly 700 miles northwest of Kauai will keep more variable winds in the forecast through Wednesday. Local radar imagery this morning shows brief passing showers mainly over East Maui, and over the Puna and Ka’u Districts on the Big Island.
Today through Wednesday…A slow moving cold front far northwest of the Hawaiian Islands will keep the high pressure ridge north of the islands in a weakened state. Light large scale east to southeasterly winds will allow local scale land and sea breezes to develop over all the smaller islands northwest of the Big Island. This southeasterly light wind pattern with a stable ridge aloft will produce isolated to scattered shower activity mainly over island mountain and interior sections in the afternoon to early evening hours. More southerly winds may bring light amounts of Volcanic smOG or VOG into the smaller islands on Tuesday and Wednesday. The exception to this rainfall forecast will be over the Puna and Ka’u Districts in Hawaii County, where southeasterly winds will drive cloud bands and brief periods of showers over the southeastern slopes of the Big Island.
New Years Eve and New Years Day…A migratory high pressure system north of the Hawaii region will drift from west to east across the Central Pacific. Building surface pressure gradients will produce moderate to breezy trade winds just in time to clear out lingering Volcanic smOG (VOG) and all the smoke from the New Years Eve celebrations. Long range model solutions continue to show a fairly stable atmosphere with just brief passing showers shifting back to traditional windward and mountain areas of each island.
Saturday and Sunday…Breezy trade winds will continue through the weekend with brief passing showers for windward and mountain areas, favoring the overnight to early morning hours.

Aviation

Clouds and showers remain focused along windward sections this morning, mainly for Oahu and islands eastward. Conditions will be primarily VFR with occasional MVFR cig/vis in showers. Weakening trade winds, particularly over the western half of the state, will allow for localized sea breezes developing this afternoon, with some inland clouds and a few light showers. Land breezes will take over tonight for those same areas, clearing out the land areas.
Winds have decreased enough this morning to warrant canceling AIRMET SIERRA for all remaining areas.

Marine

Trade winds have decreased since last evening and the Small Craft Advisory (SCA) for waters east of Oahu has been cancelled. Winds will be much lighter and favor a more east southeast direction as a front approaches from the northwest. These lighter winds are expected to persist into Wednesday. A new high building in north north of the area Thursday and Friday will cause trade winds to pick back up to breezy to locally windy levels.
Earlier choppy surf along east facing shores has subsided enough to warrant cancellation of the High Surf Advisory (HSA) there. Surf along east facing shores will pick back up toward the end of the week as trade winds strengthen once again.
A large and long period northwest swell will begin to fill in tonight. This swell will be rather long lived, with warning level surf expected during its peak Tuesday night and early Wednesday. This swell will then lower gradually into Thursday. A second and larger northwest swell will fill in on Thursday, peak Thursday night, then lower gradually into next weekend. These swells, combined with high astronomical tides, may cause some coastal inundation along low lying areas, especially during the early morning high tide cycles. Both of these swells will cause seas to exceed the 10 foot SCA threshold across exposed waters. Therefore, a new SCA has been issued for western waters for the expected northwest swell and is in effect from tonight through Tuesday night. A High Surf Warning (HSW) is in effect from tonight through Tuesday night for north and west facing shores of Niihau, Kauai and Oahu, while an HSA is in effect for the same period for north and west facing shores of Molokai and north facing shores of Maui. The SCA, HSW and HSA may all have to be extended and expanded as the week wears on.

HFO Watches/Warnings/Advisories

High Surf Advisory from 6 PM this evening to 6 AM HST Wednesday for Molokai, Maui Windward West, Maui Central Valley, Windward Haleakala.
High Surf Warning from 6 PM this evening to 6 AM HST Wednesday for Niihau, Kauai Windward, Kauai Leeward, Waianae Coast, Oahu North Shore, Oahu Koolau.
Small Craft Advisory from 6 PM this evening to 6 AM HST Wednesday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Oahu Leeward Waters.

Data Courtesy of NOAA.gov