Hilo

Tonight: Mostly cloudy with scattered showers. Haze through the night. Lows 63 to 70 near the shore to 48 to 54 at 4000 feet. Light winds becoming west up to 10 mph after midnight. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Haze through the day. Highs 78 to 83 near the shore to around 68 at 4000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Friday Night: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 64 to 70 near the shore to 48 to 55 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.

Kona

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Haze through the night. Lows around 72 near the shore to 45 to 52 near 5000 feet. Light winds. Chance of rain 40 percent.

Friday: Partly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Haze through the day. Highs around 85 near the shore to around 66 near 5000 feet. Northwest winds up to 10 mph. Chance of rain 40 percent.

Friday Night: Mostly cloudy. Haze. Lows around 72 near the shore to 45 to 53 near 5000 feet. Light winds becoming east up to 10 mph after midnight.

Waimea

Tonight: Mostly cloudy. Scattered showers in the evening. Haze through the night. Lows 62 to 69 near the shore to 51 to 59 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with isolated showers. Haze. Highs 75 to 81 near the shore to 70 to 78 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Friday Night: Mostly cloudy. Breezy and haze. Lows 62 to 70 near the shore to 53 to 60 near 3000 feet. East winds up to 20 mph.

Kohala

Tonight: Mostly cloudy. Scattered showers in the evening. Haze through the night. Lows 62 to 69 near the shore to 51 to 59 near 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with isolated showers. Haze. Highs 75 to 81 near the shore to 70 to 78 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Friday Night: Mostly cloudy. Breezy and haze. Lows 62 to 70 near the shore to 53 to 60 near 3000 feet. East winds up to 20 mph.

South Big Island

Tonight: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Haze through the night. Lows around 71 near the shore to around 49 near 5000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny. Breezy. Haze through the day. Isolated showers in the afternoon. Highs around 84 near the shore to around 66 near 5000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Friday Night: Mostly cloudy in the evening then becoming partly cloudy. Breezy and haze. Lows around 72 near the shore to around 49 near 5000 feet. East winds up to 20 mph shifting to the northeast 10 to 20 mph after midnight.

Puna

Tonight: Mostly cloudy with scattered showers. Haze through the night. Lows 63 to 70 near the shore to 48 to 54 at 4000 feet. Light winds becoming west up to 10 mph after midnight. Chance of rain 50 percent.

Friday: Partly sunny with scattered showers. Haze through the day. Highs 78 to 83 near the shore to around 68 at 4000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Friday Night: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 64 to 70 near the shore to 48 to 55 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.

Waikoloa

Tonight: Partly cloudy. Isolated showers in the evening. Haze through the night. Lows around 72 near the shore to 49 to 54 above 4000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Friday: Partly sunny with isolated showers. Haze. Highs 82 to 88 near the shore to 65 to 72 above 4000 feet. North winds up to 15 mph. Chance of rain 20 percent.

Friday Night: Mostly cloudy. Haze. Lows 69 to 74 near the shore to 49 to 55 above 4000 feet. East winds up to 15 mph.

Detailed Forecast

Synopsis

A dissipating front currently just south of Kauai will stall out and weaken near the Kauai Channel tonight into Friday. Expect continued wet weather across Kauai County during this time, with some showers moving into Oahu as well. Trade winds will begin to build back into the islands by Friday, strengthening into the moderate to breezy range from Saturday onward, with periods of enhanced showers lasting through much of next week.

Discussion

No major changes to the forecast this afternoon, mainly just small tweaks to the short term winds and PoPs. Satellite and radar imagery show a weakening frontal cloud band draped over the western end of the state, with scattered showers over Kauai, Oahu, and the Kauai Channel. Much of the activity on Kauai has been focused along the northern and western slopes and coastal areas, with several spots coming in at 1 to 3 inches of rain in the past 12 hours. This frontal band will continue to produce periods of wet weather across Kauai County and Oahu for the next couple of days as the front itself stalls and dissipates over the Kauai Channel. Most islands will continue to see light land and sea breeze conditions through tonight.
Northeasterly trade winds will quickly build in behind the front over Kauai this evening and tonight, shifting the focus of enhanced showers to north and east slopes of the Garden Isle. Trade winds will then spread eastward across the rest of the state and increase to moderate to breezy speeds on Friday as the frontal band dissipates. The remnants of the front will be pushed westward back over Kauai County late Friday into the weekend, continuing the wet weather over the western end of the state. The forecast shifts to more typical trade wind weather for the rest of the state through the weekend, albeit a bit wetter than usual. Vog will continue to linger over most islands through much of Friday until the easterly trade winds begin to push the Vog cloud in a more westward direction away from the islands by Friday night.
High confidence exists in the forecast for next week, with global models showing an extended period of easterly trade winds, with periods of enhanced showers through much of next week. As is typical with trade wind showers, the greatest shower chances and coverage will occur over windward and mountain slopes during the typical overnight to early morning hours.

Aviation

A dissipating front over Kauai will stall with northeasterly trade winds strengthening behind it. Enhanced clouds and showers over the western end of the state is expected through tonight as moisture lingers along the front. Periods of MVFR are likely within the heavier showers, mostly for the western end of the state. The eastern half of the state will see moderate to locally breezy southeasterly winds continue, with localized land breezes in sheltered areas and overall prevailing VFR conditions. Winds should then transition tonight into tomorrow to a more typical northeasterly direction as the front dissipates.
AIRMET Sierra is in effect for mtn obsc for all of Kauai and Oahu. This could continue tonight as clouds and showers linger. AIRMET Tango is in effect for tempo moderate upper level turbulence and is expected to continue through the night.
Most areas could continue to see some Vog due to the ongoing eruption of Kilauea. However, Vog is not expected to impact visibilities enough to warrant a mention in any TAF.

Marine

A slow moving and weakening cold front will stall over the Kauai Channel tonight then dissipate by Friday evening. Moderate north to northeast winds behind the front will persist. Light to moderate south to southeasterly winds ahead of the front will shift to northeast on Friday. Moderate to locally strong trade winds will become fully reestablished over the Islands by Saturday afternoon and continue into the coming week.
Small Craft Advisory conditions are expected statewide this weekend due to the arrival of both blustery trade winds and a large north swell. Conditions could develop over the western end of the state as early as Friday afternoon.
Surf along north and west facing shores will remain small this evening, but gradually build overnight due to a medium period north northwest swell (330-350). This swell is expected to produce advisory or near advisory level surf Friday and Friday night. On Saturday, a large to extra large, long period swell (350-360) will quickly build in and produce warning level surf along north facing shores with advisory level surf across west and east facing shores that will continue through the weekend. This swell, aside from being hazardous to small craft, could generate harbor surges along north facing bays and inlets.
Surf along south facing shores will remain tiny into the weekend with mainly background energy dominating. A small, long period south swell could fill in later over the weekend into early next week and provide a small boost to surf along south facing shores.
Surf along east facing shores will gradually build Friday and Saturday with the return of trade wind flow over and upstream of the state and also from the larger northerly swells wrapping into exposed areas.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov