Photo Credit: Leosan Miguel

West Side

Today: Mostly sunny with isolated showers. Haze through the day. Highs 74 to 80. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear with isolated showers. Lows 65 to 71. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Breezy. Mostly sunny with isolated showers. Highs 75 to 81. Northeast winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

South Side

Today: Sunny. Haze through the day. Highs around 84. Northeast winds 10 to 15 mph.

Tonight: Mostly clear. Lows 62 to 73. Northeast winds 10 to 15 mph.

Sunday: Sunny and breezy. Highs around 84. Northeast winds 10 to 20 mph.

North Shore

Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Haze. Highs 76 to 81 near the shore to around 65 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 67 near the shore to around 50 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs around 78 near the shore to around 64 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Central Maui

Today: Sunny and breezy. Haze in the morning. Isolated showers in the afternoon. Highs 78 to 84. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows 63 to 68. Northeast winds 10 to 20 mph.

Sunday: Mostly sunny. Breezy. Isolated showers in the morning. Highs 78 to 84. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Upcountry

Today: Sunny. Isolated showers in the morning, then scattered showers in the afternoon. Haze through the day. Highs around 63 at the visitor center to around 65 at the summit. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Mostly clear. Haze in the evening. Scattered showers in the evening, then isolated showers after midnight. Lows around 45 at the visitor center to around 42 at the summit. East winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Mostly sunny with scattered showers. Highs 56 to 67. East winds 10 to 15 mph. Chance of rain 50 percent.

East Maui

Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Haze. Highs 76 to 81 near the shore to around 65 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 67 near the shore to around 50 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs around 78 near the shore to around 64 near 5000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Lanai City

Today: Sunny and breezy. Haze in the morning. Isolated showers in the afternoon. Highs 70 to 78. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Breezy. Lows 60 to 65. Northeast winds 10 to 20 mph.

Sunday: Sunny and breezy. Highs 71 to 78. Northeast winds 10 to 20 mph.

Kaunakakai

Today: Breezy. Mostly sunny with isolated showers. Highs 67 to 84. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 55 to 71. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Sunday: Breezy. Mostly sunny with isolated showers. Highs 67 to 84. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

An approaching weakening front, coupled with an upper level trough, will bring enhanced trade wind showers this weekend. A new ridge building north of the islands behind the front will bring trade winds to the region for the start of the new year.

Discussion

The forecast has been updated to align it with the latest from the National Blend of Models (NBM) with little difference between the global models. As mentioned in the evening discussion, the latest University of Hawaii vog model output was used to identify areas of haze due to the Halemaumau emissions. No change to the forecast philosophy this morning.
The overnight Lihue sounding has come in with 0.99 inches of precipitable water (PW), which corresponds well with the CIMSS satellite derived PW. Meanwhile, Hilo has come in with 1.24 inches, which is above both CIMSS and GOES-18 derived PW. Both CIMSS and GOES-18 derived PW show drier air along the front than earlier in the evening. This could be the surface feature weakening, but it will be difficult to tell with any certainty until the later this morning when the front is expected to reach the islands.
The global models continue to depict the associated upper level trough deepening today and tonight as is pushes down the island chain. With the surface feature expected to weakening and get washed out, surface winds are expected to turn to a more typical trade wind direction. The upper level trough will introduce a bit more instability which could help to enhance trade wind showers.
There remains a non-zero chance for a thunderstorm or two near the islands tonight or tomorrow, but confidence remains low. The ECMWF has shown a bit of an uptick in the possibility tonight near Oahu, as has the GFS, with both models previously showing a decrease in the possibility. The high resolution models arw and FV3 are also keying in on the possibility. Temperatures at 500 mb dip down to around -14 C, with PW values within normal range for this time of year. Suspect the trades filtering in at the surface will help to disrupt any organized convection. The models continue to show a slightly greater possibility for thunderstorms to the northeast along the portion of the front that is expected to remain more intact. As such, still haven't put thunder in the forecast, but will continue to keep an eye on the situation.
The front is being pushed down the island chain by a high pressure system behind the front that will move from west to east north of 30N over the coming days. By Sunday night, the high is expected to to the far northeast of the islands, with a ridge extending to the southwest from the high. This will maintain moderate trade winds into the new year.
A hot spot over Halemaumau Crater on the Big Island continues to be seen on infrared satellite imagery. The University of Hawaii (UH) Vog Model show SO2 emissions should start to leave the smaller islands behind today as trade winds build back in at the surface. By tonight, the vog should be confined to portions of the Big Island and the waters to the southwest.

Aviation

Light to moderate east southeast winds will continue over the eastern end of the state, while light to moderate northerly winds begin to filter in to the western end ahead of the front. A weak front approaching Kauai and Oahu threatens MVFR cigs/vsbys along with slightly stronger trades over the western end of the state through the morning hours. Shower coverage remains sparse and light statewide. Building trades will bring a return to a typical distribution of clouds and showers focused on windward and mauka areas.
No AIRMETs in effect. AIRMET Sierra for mountain obscuration may be needed for windward portions of Kauai and Oahu during the morning hours.

Marine

A weak cold front passing just north of the state will dissipate later today. Fresh to strong northeast to east trade winds will build in behind the front. The Small Craft Advisory is now in effect through Saturday night for a combination of hazardous wind and sea conditions. Seas exceeding 10 ft over northwest exposed waters are expected through at least this evening and possibly beyond. Freshening trade winds are expected to reach or exceed 25 knots this weekend across most windward waters and the waters surrounding Kauai as well as the typically windy channels.
The current northwest (310-340) swell peaked Friday evening and is expected to gradually decline over the next 36 to 72 hours. The swell is still running about 2 feet above guidance, but should come more in line with Wavewatch later today or this evening. Surf along exposed west facing shores of the Big Island remains at warning levels this morning. Along north and west facing shores of Kauai and Oahu and north facing shores of Maui, surf has already declined to advisory levels. Surf is expected to fall even further this evening.
The next significant northwest swell is not expected until middle of next week at the earliest.
Surf along south and east-facing shores will remain small through the middle of next week.

Fire weather

No critical fire weather conditions are expected for the next seven days. Expecting trade winds to become established across the islands from north to south today, with some enhanced trade wind showers. A more typical trade wind pattern is expected Monday onwards.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Oahu North Shore, Maui Windward West, Kauai North, Molokai Windward, Molokai North, Molokai West, Maui Central Valley North, Windward Haleakala.
High Surf Warning until 6 PM HST this evening for Kona, Kohala, Big Island South.
Small Craft Advisory until 6 AM HST Sunday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters, Kaiwi Channel, Maui County Windward Waters, Alenuihaha Channel, Big Island Windward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov