Hilo

Rest Of Tonight: Mostly cloudy with scattered showers. Lows 59 to 67 near the shore to 48 to 54 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs 75 to 81 near the shore to 61 to 66 at 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Sunday Night: Mostly cloudy with scattered showers. Lows 58 to 67 near the shore to 47 to 55 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Kona

Rest Of Tonight: Mostly clear. Haze. Lows around 69 near the shore to 40 to 48 near 5000 feet. Light winds.

Sunday: Mostly sunny. Haze through the day. Isolated showers in the afternoon. Highs 80 to 85 near the shore to around 66 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Sunday Night: Mostly clear. Haze. Lows around 69 near the shore to 41 to 48 near 5000 feet. Light winds.

Waimea

Rest Of Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 59 to 68 near the shore to 51 to 59 near 3000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.

Sunday: Breezy. Mostly sunny with isolated showers. Highs 60 to 80. East winds 10 to 20 mph. Chance of rain 20 percent.

Sunday Night: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Scattered showers. Lows 58 to 68 near the shore to 51 to 58 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Rest Of Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows 59 to 68 near the shore to 51 to 59 near 3000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.

Sunday: Breezy. Mostly sunny with isolated showers. Highs 60 to 80. East winds 10 to 20 mph. Chance of rain 20 percent.

Sunday Night: Mostly cloudy in the evening then becoming partly cloudy. Breezy. Scattered showers. Lows 58 to 68 near the shore to 51 to 58 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Rest Of Tonight: Mostly clear. Haze. Lows around 70 near the shore to around 49 near 5000 feet. Northeast winds up to 15 mph.

Sunday: Sunny and breezy. Haze through the day. Isolated showers in the afternoon. Highs around 83 near the shore to around 66 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Sunday Night: Mostly clear. Haze. Lows around 71 near the shore to around 49 near 5000 feet. Northeast winds 10 to 15 mph.

Puna

Rest Of Tonight: Mostly cloudy with scattered showers. Lows 59 to 67 near the shore to 48 to 54 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs 75 to 81 near the shore to 61 to 66 at 4000 feet. North winds up to 15 mph. Chance of rain 50 percent.

Sunday Night: Mostly cloudy with scattered showers. Lows 58 to 67 near the shore to 47 to 55 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Waikoloa

Rest Of Tonight: Mostly clear. Breezy. Haze after midnight. Lows 67 to 72 near the shore to 44 to 50 above 4000 feet. East winds up to 20 mph shifting to the southeast 10 to 15 mph after midnight.

Sunday Night: Mostly clear. Breezy and haze. Lows 67 to 72 near the shore to 45 to 50 above 4000 feet. East winds up to 20 mph becoming 10 to 15 mph after midnight.

Monday: Sunny. Haze through the day. Highs 64 to 87. East winds 10 to 15 mph shifting to the north in the afternoon. Gusts up to 35 mph.

Detailed Forecast

Synopsis

A front dissipating over the western end of the state coupled with an upper level trough will bring enhanced trade wind showers through the 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 weakening cold front is not as easily distinguishable on visible satellite imagery as it was this morning. This is due to some prefrontal clouds and showers that are moving into Maui County this afternoon and blending in with the clouds and showers streaming into Kauai and Oahu that are associated with the gradually dissipating frontal boundary. Showers will continue to move into windward and mauka areas, with a focus over Kauai and Oahu, through tonight and into tomorrow as the front stalls and further dissipates. Moderate to breezy east-northeast winds will continue to filter in across the western end of the state tonight as a surface ridge builds behind the frontal boundary, with slightly weaker easterly trades moving across the rest of the island chain.
An upper level trough will continue to dip down across the state through tomorrow, then form a cutoff low to the southeast of the Big Island. The proximity of this feature to the island chain and its accompanying instability will likely help to enhance windward showers through the rest of the weekend and into early next week. There might be enough instability to support isolated thunderstorms this evening with 500 mb temperatures potentially dropping to -15C, but relatively limited/shallow moisture and weak surface forcing with the dissipating front and gradually building trades continue to be the limiting factors.
The subtropical ridge will build back over the islands from the west early next week, pushing the upper level trough east of the Big Island by Monday night, which should allow a more typical trade wind pattern to commence through the end the year and into the start of the new. Then as a series of fronts approach from the northwest, winds will once again veer east-southeast by the end of next week. The next front to make it across at least the western end of the state looks to arrive sometime next weekend into early next week.
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 shows that SO2 emissions have mostly cleared out of the smaller islands and should remain confined to portions of the Big Island and the waters to the southwest through the weekend.

Aviation

A weak front over the Kauai Channel continues to bring low clouds and scattered showers to the western half of the state. Expect areas of MVFR cigs across Kauai and local MVFR cigs over windward Oahu. VFR conditions continue elsewhere with isolated showers. Trade winds will continue to strengthen overnight bringing a return of clouds and showers that are focused over windward and mauka areas.
AIRMET Sierra for tempo mountain obscuration remains in effect for Kauai and may be necessary over windward portions of the other islands late tonight.

Marine

The current northwest (310-340) swell has rapidly declined through the day today, with current observations even a bit below model guidance. Surf along exposed north and west facing shores has declined as a result, with heights now just below advisory levels for the smaller islands. Surf along the exposed west facing shores of the Big Island is down, but holding at advisory levels. Therefore, the High Surf Advisory has been cancelled for the smaller islands and the High Surf Warning for west facing Big Island has been downgraded to a High Surf Advisory. This swell and associated surf will continue to decline into early next week. 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.
A weakening front has become stationary over the western end of the island chain and is expected to dissipate within the next day. Fresh to strong northeast trade winds are filling in over and around Kauai this afternoon according to recent ASCAT pass. Trades will return tonight around the windy waters around Maui County and the Big Island as well tonight. Combined with the aforementioned northwest swell now below 10 feet, the Small Craft Advisory has been rearranged to include only these areas affected by the increasing trades and extended through Sunday afternoon. After Sunday, fresh to locally strong trades will likely continue for the typically windy waters around Maui and the Big Island for several more days.

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 through the rest of this weekend, 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 AM HST Sunday for Kona, Kohala, Big Island South.
Small Craft Advisory until 6 PM HST Sunday for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov