Photo Credit: Joan M. Flake

West Side

Today: Sunny, with a high near 76. West northwest wind around 7 mph.

Tonight: Mostly clear, with a low around 60. North northeast wind 7 to 10 mph.

Friday: Sunny, with a high near 77. Northeast wind around 6 mph becoming light and variable.

South Side

Today: Isolated showers before noon. Mostly sunny, with a high near 76. Breezy, with a north northeast wind 11 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 58. Breezy, with a north northeast wind 10 to 15 mph, with gusts as high as 21 mph.

Friday: Mostly sunny, with a high near 77. Northeast wind 5 to 10 mph becoming light and variable in the afternoon.

North Shore

Today: Scattered showers before noon. Mostly sunny, with a high near 74. Northwest wind 8 to 13 mph. Chance of precipitation is 30%.

Tonight: Isolated showers. Partly cloudy, with a low around 59. North wind 6 to 8 mph becoming east after midnight. Chance of precipitation is 20%.

Friday: Isolated showers. Sunny, with a high near 75. East wind around 6 mph becoming calm in the afternoon. Chance of precipitation is 20%.

Central Maui

Today: Isolated showers before noon. Mostly sunny, with a high near 76. North wind 6 to 11 mph. Chance of precipitation is 20%.

Tonight: Isolated showers. Mostly clear, with a low around 57. North wind 5 to 9 mph. Chance of precipitation is 20%.

Friday: Isolated showers. Mostly sunny, with a high near 77. North wind around 5 mph becoming calm in the afternoon. Chance of precipitation is 20%.

Upcountry

Today: Isolated showers before 1pm. Mostly sunny, with a high near 62. Calm wind becoming west 5 to 8 mph in the afternoon. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 47. Light and variable wind becoming east southeast around 5 mph.

Friday: Mostly sunny, with a high near 62. Light and variable wind becoming west southwest 6 to 11 mph in the morning.

East Maui

Today: Scattered showers, mainly before noon. Mostly sunny, with a high near 74. Breezy, with a north northwest wind 14 to 18 mph, with gusts as high as 25 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch possible.

Tonight: Isolated showers. Partly cloudy, with a low around 55. North northwest wind 10 to 14 mph, with gusts as high as 20 mph. Chance of precipitation is 20%.

Friday: Isolated showers. Mostly sunny, with a high near 75. North northwest wind 5 to 10 mph becoming light and variable in the afternoon. Chance of precipitation is 20%.

Lanai City

Today: Mostly sunny, with a high near 70. Breezy, with a north northwest wind 11 to 16 mph, with gusts as high as 23 mph.

Tonight: Mostly clear, with a low around 55. Northeast wind 8 to 11 mph.

Friday: Mostly sunny, with a high near 71. North northeast wind 5 to 8 mph becoming light and variable.

Kaunakakai

Today: Sunny, with a high near 74. Breezy, with a north northwest wind around 15 mph, with gusts as high as 21 mph.

Tonight: Isolated showers after midnight. Mostly clear, with a low around 59. North northeast wind 7 to 14 mph, with gusts as high as 20 mph. Chance of precipitation is 20%.

Friday: Isolated showers before noon. Sunny, with a high near 75. Light and variable wind becoming west northwest 5 to 8 mph in the afternoon. Chance of precipitation is 20%.

Detailed Forecast

Synopsis

A weakening cold front will move into the Big Island this morning, then shift east of the state tonight. Showers will be most prevalent along and ahead of this front, with a slight chance of thunderstorms holding over the Big Island through this evening. Meanwhile, much drier and cooler conditions will build in across the smaller islands today, with the cooler and drier air overspreading the Big Island tonight. Cool and dry conditions, with light winds will then prevail Friday through the weekend. A few light passing showers will move through north and west facing slopes and coasts at times, with a shower or two developing during the day over interior and mauka areas. Another weather system is expected to approach the state early next week, possibly bringing another round of widespread rainfall to the island chain.

Discussion

Currently at the surface, a weakening cold front has cleared Maui and is approaching the Big Island early this morning. Meanwhile, a 1024 mb high is centered around 1200 miles west-northwest of Kauai. Moderate to breezy north-northwesterly winds are in place across the smaller islands, while winds over the Big Island remain weaker with land breezes present in many areas. Infrared satellite imagery shows mostly cloudy skies over most of Kauai and the Big Island, while partly cloudy conditions prevail over most of Oahu and Maui County. Radar imagery shows scattered showers moving the Big Island in advance of the front, while post-frontal showers are focused mainly over north and west coasts and slopes of the smaller islands, with coverage the greatest across Kauai. Main short term concerns revolve around winter weather headlines and the potential for thunder today.
The weakening cold front will continue to push eastward into the Big Island early this morning, then gradually shift eastward through the day, exiting to the east of the state this evening. The breezy north-northwesterly winds behind the front will begin to ease to moderate levels as the day progresses, then lower further tonight as high pressure begins to nose in from the west. Winds are expected to become light and variable Friday through the weekend, as the axis of high pressure settles right over the islands. This is expected to result in daytime sea breezes and overnight land breezes statewide. Model solutions appear to be converging on a new cold front approaching from the west Monday, then moving southeastward through the island chain Monday night and Tuesday. This would bring breezy southwesterly winds in advance of the front, with breezy northwesterly winds building in behind it for Tuesday night and Wednesday.
As for the remaining forecast details, much drier and cooler conditions are expected across the smaller islands today and tonight, with showers limited primarily to north and west facing slopes and coasts. The weakening and slow moving cold front is expected to keep shower coverage higher over the Big Island today and tonight however, as it moves through and slowly exits to the east. Although deep layer moisture will be on the decrease, plenty of lingering instability will remain over the Big Island into this evening, so a slight chance of thunderstorms has been added to the forecast through this evening. Fairly dry weather is then expected statewide Friday through Sunday night, with a few light showers possible in north and west facing slopes and coasts due to the prevailing west-northwest boundary layer flow, and a few light interior and mauka showers possible in the afternoon hours aided by sea breezes. Rain chances then appear to increase late Monday through Tuesday in association with then next cold front forecast to move through the islands. Drier weather appears to return by the middle of next week as high pressure noses in from the west.
As for ongoing headlines… Moisture remains deep enough and temperatures cold enough to support wintry weather over the Big Island summits and the Haleakala summit through mid morning. As a result, the Winter Weather Advisory is now in effect for the Big Island and Haleakala summits through 10 AM this morning.

Aviation

A weakening front will move east of the Big Island late today. Lingering clouds, scattered showers and isolated thunderstorms are expected over and around the Big Island. Elsewhere, VFR conditions will prevail with low topped stratocumulus riding in on north winds. Some of the low SC will cause tempo MVFR conditions along NE through NW slopes, especially over Kauai.
AIRMET Sierra for mountain obscuration will be modified as conditions warrant.

Marine

A weakening front is approaching the Big island this early morning and continues to move steadily east. Some gusty southwest and west winds and possible isolated thunderstorms remain a threat in the waters around the Big Island through later morning.
For building seas associated with an incoming large northwest swell, a Small Craft Advisory (SCA) has been posted for most coastal waters, with seas rising from west to east across the island chain through today.
The new, large northwest swell will lead to High Surf Warning/Advisory conditions today for north- and/or west-facing shores of most of the islands. The swell will begin to gradually subside beginning Friday over the western islands and Friday night elsewhere. The latest model runs, however, show northwest swell energy remaining somewhat elevated through the weekend.
No significant swells are expected elsewhere through early next week.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 AM HST Friday for Niihau, Kauai Windward, Kauai Leeward, Waianae Coast, Oahu North Shore, Oahu Koolau.
High Surf Advisory until 6 AM HST Friday for Molokai, Maui Windward West, Maui Central Valley, Windward Haleakala, Kona, Kohala.
Winter Weather Advisory until 10 AM HST this morning for Haleakala Summit, Big Island Summits.
Small Craft Advisory until 6 AM HST Friday 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, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov