Photo Credit: Tyler Rooke

West Side

Today: Isolated showers before 1pm. Mostly sunny, with a high near 84. Light and variable wind becoming west northwest around 6 mph in the afternoon. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 65. West wind around 6 mph becoming light and variable.

Friday: Sunny, with a high near 84. North wind 5 to 11 mph becoming southwest in the afternoon.

South Side

Today: Mostly sunny, with a high near 84. Calm wind becoming west around 6 mph in the afternoon.

Tonight: Isolated showers between 7pm and 1am. Partly cloudy, with a low around 63. Northeast wind around 5 mph becoming calm after midnight. Chance of precipitation is 20%.

Friday: Isolated showers after 1pm. Mostly sunny, with a high near 84. Northeast wind 5 to 8 mph becoming west in the afternoon. Chance of precipitation is 20%.

North Shore

Today: Isolated showers. Mostly sunny, with a high near 82. East wind 10 to 14 mph, with gusts as high as 18 mph. Chance of precipitation is 20%.

Tonight: Partly cloudy, with a low around 64. East wind 5 to 13 mph becoming south southeast after midnight.

Friday: Mostly sunny, with a high near 82. South southeast wind 5 to 11 mph becoming north in the morning.

Central Maui

Today: Isolated showers. Mostly sunny, with a high near 82. Breezy, with a northeast wind 7 to 16 mph, with gusts as high as 22 mph. Chance of precipitation is 20%.

Tonight: Partly cloudy, with a low around 62. East northeast wind 5 to 7 mph becoming calm in the evening.

Friday: Mostly sunny, with a high near 82. Light and variable wind becoming north northeast 5 to 10 mph in the afternoon.

Upcountry

Today: Mostly sunny, with a high near 69. Calm wind becoming west northwest around 6 mph.

Tonight: Partly cloudy, with a low around 52. Calm wind becoming northeast around 5 mph after midnight.

Friday: Isolated showers after noon. Mostly sunny, with a high near 70. Light and variable wind becoming east 5 to 9 mph in the afternoon. Chance of precipitation is 20%.

East Maui

Today: Scattered showers. Partly sunny, with a high near 80. Light and variable wind becoming southeast 8 to 13 mph in the morning. 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 60. East southeast wind 10 to 13 mph. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch possible.

Friday: Scattered showers before noon. Mostly sunny, with a high near 80. Breezy, with a southeast wind 8 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.

Lanai City

Today: Isolated showers after noon. Mostly sunny, with a high near 76. Breezy, with a northeast wind 16 to 21 mph becoming light and variable in the afternoon. Winds could gust as high as 29 mph. Chance of precipitation is 20%.

Tonight: Isolated showers before midnight. Partly cloudy, with a low around 63. Light and variable wind becoming north northwest 5 to 10 mph after midnight. Chance of precipitation is 20%.

Friday: Isolated showers after noon. Mostly sunny, with a high near 76. North northwest wind 8 to 13 mph becoming east northeast in the afternoon. Chance of precipitation is 20%.

Kaunakakai

Today: Isolated showers before noon. Mostly sunny, with a high near 81. East wind 6 to 11 mph becoming light and variable in the afternoon. Chance of precipitation is 20%.

Tonight: Mostly clear, with a low around 65. Calm wind becoming north 5 to 8 mph after midnight.

Friday: Isolated showers after noon. Sunny, with a high near 81. North wind 6 to 13 mph becoming east in the afternoon. Chance of precipitation is 20%.

Detailed Forecast

Synopsis

A weak stationary front will dissipate across the central islands today. A second front is expected to approach from the northwest tonight and Friday, then stall just northwest of Kauai Friday night and Saturday. A third and stronger front is forecast to move through the area Sunday into early next week, potentially bringing some heavy rainfall to portions of the island chain.

Discussion

Currently at the surface, a front is nearly stationary over Maui County this morning. Meanwhile, a 1019 mb high is centered around 400 miles north-northeast of Honolulu. Infrared satellite imagery shows partly cloudy conditions over most of the state, with some more extensive cloud cover over windward sections of Oahu, Molokai and Maui. Radar imagery shows scattered showers over windward areas from Oahu to Maui, with some showers spilling leeward as well. Elsewhere, very little shower activity is seen. Main forecast concern revolves around the potential for unsettled weather late in the weekend through early next week.
Today… The front is expected to dissipate today, as the high north of the islands builds rapidly eastward. Moderate trade winds are expected across the island chain, although the approach of the next in a series of fronts may ease the trades enough over the western islands this afternoon to allow for localized sea breezes. Scattered showers are expected in close proximity to the front this morning. A drier and more typical windward/mauka focused shower pattern is expected this afternoon, although a few leeward showers may develop due to sea breeze development.
Tonight through Saturday… The next front will approach from the northwest tonight and Friday, then stall out and gradually dissipate around 100 miles northwest of Kauai Friday night and Saturday. Light and variable winds are expected to persist over the western islands during this time, with overnight land breezes and daytime sea breezes. Meanwhile, light to moderate east to southeast winds should prevail over the eastern end of the state. Fairly dry weather is expected to continue through the period statewide, with no significant rainfall expected.
Saturday night through next Wednesday… Forecast uncertainty increases considerably late in the weekend through the first half of next week, as model consensus and individual model run to run continuity remains poor. What the models do agree upon however, is that another cold front will approach and move into the islands late in the weekend. What they disagree on is the progressiveness of the front, with the GFS showing an island clearing frontal passage, while the ECMWF hangs the front up over the island chain. There is the potential that a very wet pattern could set up across at least portions of the state Sunday through early next week, with heavy rainfall and thunderstorms not out of the question. Given the uncertainty, will follow a blended forecast approach until details become more clear. This will result in keeping rainfall in the forecast statewide through the entire extended period.

Aviation

Radar shows a thin line of showers, marking the remnants of the front, draped across West Maui through Molokai. These showers appears to be dwindling.
In the wake of the front’s passing earlier in the evening, low level moisture is hung up over windward Oahu. This moisture has the potential in turning into scattered showers later this morning. A patch of clouds currently 50 miles southeast of Kauai, poses a threat to that island this afternoon, as the prevailing easterly trade winds, veer to the southeast by this afternoon. Oahu, Molokai, and Lanai, may also encounter a few afternoon showers as the easterly trade winds give way to sea breezes.
No AIRMETs right now. Do expect some spotty/isolated MVFR ceilings/showers this morning, especially the windward and mountain areas of Molokai and Oahu. AIRMET Sierra may eventually be needed mountain obscuration on any of the smaller islands late this morning. The Big Island looks fine right now. The lee side of the Big Island will likely go through its usual morning sun, then afternoon/evening clouds with a few showers.
AIRMET Tango for high level turbulence between FL320/420 will be extended as the core of the jet max passes north of the islands this morning. The AIRMET could be lowered by 22z.

Marine

A stationary front over Maui County will dissipate today. Moderate to fresh northeast to east trade winds will briefly return, as a high pressure system passes by north of the island chain. Wind directions will then veer towards the southeast and weaken tonight through Friday ahead of another cold front approaching the islands from the northwest. A Small Craft Advisory (SCA) remains in effect for most Hawaiian coastal waters through Friday morning due to a large northwest swell moving through the region spreading 10 to 16 ft seas over most of our coastal waters and channels.
A series of large north to northwest swells will impact the state through the weekend. The current building northwest swell will peak today then gradually lower tonight. A brief overlapping northerly swell (350-360 direction) will arrive tonight, peaking on Friday. Warning level surf is forecast for north and west facing shores of the smaller islands today and tonight. Surf heights along the north facing shores of the Big Island will build to advisory levels today. Warning level surf heights over the smaller islands will lower to advisory levels Friday.
An extra large northwest swell (310-330 direction) will arrive Friday evening, quickly building to warning levels Saturday morning according to the Wave Watch III forecast at the Waimea Buoy. These large swell heights will produce surf well above warning thresholds, holding through Saturday, and then slowly lowering from Saturday night through Sunday. Surf along north and west facing shores of the smaller islands will remain well above warning levels through the weekend. The northwest swell event this weekend has the potential to produce the largest surf of the season.
Another extra large northwest swell (300-330 direction) builds into Hawaii waters on Monday. Wave Watch III holds warning level surf from Monday into Monday night. This northwest swell diminishes Tuesday as another north swell (340-360 direction) builds into Hawaiian waters, with moderate swell heights holding through Wednesday.
Surf along south and east facing shores will remain small through the first half of next week. Some larger surf may wrap into east facing shores exposed to the north and northwest swells.
A combination of the large surf this week coinciding with peak monthly high tides may worsen beach erosion along shorelines exposed to north and west swells during the early morning hours.

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, Molokai, Maui Windward West, Maui Central Valley, Windward Haleakala.
High Surf Advisory until 6 AM HST Friday for Big Island North and East.
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, Alenuihaha Channel, Big Island Windward Waters.

Data Courtesy of NOAA.gov