Photo Credit: Tyler Rooke

West Side

New Year’s Day: Isolated showers before noon. Sunny, with a high near 82. Windy, with an east northeast wind 9 to 14 mph increasing to 20 to 25 mph in the morning. Winds could gust as high as 36 mph. Chance of precipitation is 20%.

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

Saturday: Isolated showers before noon. Sunny, with a high near 82. East northeast wind around 14 mph, with gusts as high as 18 mph. Chance of precipitation is 20%.

South Side

New Year’s Day: Isolated showers after noon. Mostly sunny, with a high near 82. Breezy, with a light and variable wind becoming east northeast 10 to 15 mph in the afternoon. Winds could gust as high as 21 mph. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Mostly clear, with a low around 68. Breezy, with an east northeast wind 13 to 15 mph, with gusts as high as 21 mph. Chance of precipitation is 20%.

Saturday: Isolated showers after noon. Sunny, with a high near 82. East wind around 14 mph, with gusts as high as 18 mph. Chance of precipitation is 20%.

North Shore

New Year’s Day: Scattered showers, mainly before noon. Mostly sunny, with a high near 80. Windy, with an east wind 18 to 25 mph, with gusts as high as 36 mph. Chance of precipitation is 30%.

Tonight: Isolated showers. Partly cloudy, with a low around 69. Breezy, with an east wind 18 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 20%.

Saturday: Scattered showers, mainly before noon. Mostly sunny, with a high near 80. Breezy, with an east wind 17 to 22 mph, with gusts as high as 31 mph. Chance of precipitation is 30%.

Central Maui

New Year’s Day: Isolated showers. Mostly sunny, with a high near 80. Windy, with a northeast wind 14 to 19 mph increasing to 24 to 29 mph in the afternoon. Winds could gust as high as 41 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Partly cloudy, with a low around 67. Breezy, with an east northeast wind 16 to 21 mph, with gusts as high as 29 mph. Chance of precipitation is 20%.

Saturday: Isolated showers. Mostly sunny, with a high near 80. Windy, with an east northeast wind 15 to 24 mph, with gusts as high as 34 mph. Chance of precipitation is 20%.

Upcountry

New Year’s Day: Mostly sunny, with a high near 68. Breezy, with a light and variable wind becoming east 17 to 22 mph in the afternoon. Winds could gust as high as 31 mph.

Tonight: Partly cloudy, with a low around 57. Breezy, with an east wind around 22 mph, with gusts as high as 31 mph.

Saturday: Mostly sunny, with a high near 69. Breezy, with an east northeast wind 18 to 22 mph, with gusts as high as 31 mph.

East Maui

New Year’s Day: Scattered showers. Partly sunny, with a high near 78. Breezy, with an east northeast wind 11 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.

Tonight: Scattered showers. Mostly cloudy, with a low around 65. Breezy, with an east wind around 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.

Saturday: Scattered showers. Partly sunny, with a high near 78. Breezy, with an east 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

New Year’s Day: Isolated showers after noon. Mostly sunny, with a high near 75. Very windy, with a northeast wind 21 to 31 mph, with gusts as high as 45 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 62. Breezy, with an east northeast wind around 21 mph, with gusts as high as 29 mph.

Saturday: Isolated showers after noon. Mostly sunny, with a high near 75. Breezy, with an east northeast wind 16 to 20 mph, with gusts as high as 28 mph. Chance of precipitation is 20%.

Kaunakakai

New Year’s Day: Mostly sunny, with a high near 80. Windy, with an east northeast wind 14 to 19 mph increasing to 21 to 26 mph in the afternoon. Winds could gust as high as 38 mph.

Tonight: Mostly clear, with a low around 70. Windy, with an east northeast wind 23 to 26 mph, with gusts as high as 38 mph.

Saturday: Mostly sunny, with a high near 80. Windy, with an east northeast wind 21 to 23 mph, with gusts as high as 32 mph.

Detailed Forecast

Synopsis

A high pressure system slowly passing by north of the Hawaiian Islands will keep breezy to windy trade winds in the forecast through the day today. Breezy trades will continue through the weekend with passing showers drifting over windward and mountain areas. More isolated shower activity may develop over leeward slopes of each island. Trade wind speeds will decrease to more moderate levels for the first half of next week, as a cold front passes by north of the island chain.

Discussion

Satellite imagery this morning shows bands of clouds moving in over windward slopes from Oahu to the Big Island. These clouds will produce passing showers mainly over windward and mountain sections today. More isolated shower coverage remains in the forecast over leeward areas. To the north, a dissipating cold front is stalling out roughly 250 miles north of Kauai as a high pressure system drifts from west to east north of the front. A weak subtropical jet stream will bring some scattered to broken high cirrus clouds to the islands enhancing sunrise and sunset colors.
Breezy to windy trade winds are forecast today with a wind advisory in effect for most of Maui and Hawaii Counties. These strong northeast trade winds will continue into the evening hours and then become more breezy through the weekend. Trade wind speeds will decrease to more moderate levels for the first half of next week, as a cold front passes by north of the island chain.
Passing showers in this extended trade wind weather pattern will continue to favor windward and mountain areas, trending higher in the overnight to early morning hours, with less rainfall activity forecast over leeward areas.
Global weather models are in good agreement on this weather pattern through the next seven days. Expect subtle day to day changes in the island rainfall patterns as small scale convergence features in the upstream trade winds may produce some differences in rainfall coverage and amounts.
We wish you all a Happy New Year!

Aviation

Breezy to windy trades will prevail today and tonight as high pressure slides by to the north of the island chain. Low clouds and showers will favor windward and mauka areas, with some of these showers spreading leeward due to the strong trades.
AIRMET Sierra is in effect for mountain obscuration across windward sections of Kauai, Oahu, Molokai, Maui and the Big Island. Conditions are expected to improve later this morning.
AIRMET Tango remains in effect for moderate low level turbulence over and downwind of the terrain of all islands. These conditions will persist during the next couple days.
AIRMET Tango will likely be needed for moderate upper level turbulence between FL250 and FL400, either later this morning.

Marine

High pressure building north of the state will tighten the pressure gradient back across the chain enough to strengthen trade winds through the day today. Widespread strong trades will occur over all local near and offshore waters with near gales expected over the windier channels. A Gale Warning is now in effect for the Alenuihaha Channel through this afternoon as strong winds will frequently gust to gale force magnitudes. Winds are forecast to weaken to more moderate to locally fresh speeds early next week as the high shifts further east and relaxes the pressure gradient. The combination of large northwest swells and strengthened trades will create rough seas that will exceed the Small Craft Advisory (SCA) sea height threshold of 10 feet across all Hawaiian waters the next several days. An SCA is in effect for all waters through Saturday afternoon.
A steady decline in surf will occur through the day as these recent large northwest swells gradually diminish through Saturday. Surf heights of greater than 30 feet along northern exposed shorelines and 20 feet along west shores are peaking early this morning and are anticipated to fall back to advisory levels by this evening. Recent northwest offshore buoy observations are depicting a leveling off of these latest northwest swells. This morning’s nearshore buoy readings near Waimea Bay are still holding fairly strong with around 10 foot, 15 second swell energy moving in. Swells are expected to slowly veer more north as energy steady declines Friday into Saturday. The new year will begin with a series of weekend smaller, long period north northwest swells. A new larger, long period northwest swell will build in Sunday into Monday. These early week swells will likely lift north and possibly west-facing surf back up to advisory levels.The combination of recently large swells and higher astronomical tides may result in minor coastal water inundation within low-lying areas during the New Year’s morning high tides.
Surf along eastern exposed shores will steadily rise today in response to amped up trades both locally and upstream of the state. Surf along east-facing shores could reach advisory thresholds either today or tomorrow (Saturday). With no anticipated incoming southerly swell energy, south-facing shore surf should remain low even by winter season standards.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 PM HST this evening for Niihau, Kauai Windward, Kauai Leeward, Waianae Coast, Oahu North Shore, Oahu Koolau, Molokai, Maui Windward West, Maui Central Valley, Windward Haleakala.
Wind Advisory until 6 PM HST this evening for Lanai, Kahoolawe, Maui Windward West, Maui Leeward West, Maui Central Valley, Windward Haleakala, Leeward Haleakala, South Big Island, Big Island North and East, Kohala.
Small Craft Advisory until 6 PM HST Saturday 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 from 6 AM this morning to 6 PM HST this evening for Alenuihaha Channel.
Small Craft Advisory from 6 PM this evening to 6 PM HST Saturday for Alenuihaha Channel.

Data Courtesy of NOAA.gov