Hilo

Tonight: Mostly cloudy. Scattered showers in the evening, then occasional showers after midnight. Lows around 66 near the shore to around 52 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 80 percent.

Friday: Mostly cloudy. Occasional showers early in the morning, then scattered showers in the late morning and afternoon. Highs around 80 near the shore to 64 to 69 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 80 percent.

Friday Night: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows around 65 near the shore to around 51 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 70 percent.

Kona

Tonight: Partly cloudy with isolated showers. Haze. Lows around 68 near the shore to around 53 near 5000 feet. Light winds. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers early in the morning, then partly sunny with scattered showers in the late morning and afternoon. Haze through the day. Highs 79 to 84 near the shore to around 70 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.

Friday Night: Partly cloudy. Isolated showers in the evening. Haze through the night. Lows around 67 near the shore to around 52 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 65 near the shore to 51 to 59 near 3000 feet. East winds up to 25 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 79 near the shore to 70 to 77 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Friday Night: Breezy. Mostly cloudy with scattered showers. Lows around 64 near the shore to 50 to 58 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 65 near the shore to 51 to 59 near 3000 feet. East winds up to 25 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 79 near the shore to 70 to 77 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Friday Night: Breezy. Mostly cloudy with scattered showers. Lows around 64 near the shore to 50 to 58 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Haze through the night. Lows around 68 near the shore to around 52 near 5000 feet. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Breezy. Haze through the day. Isolated showers in the late morning and afternoon. Highs around 82 near the shore to around 71 near 5000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

Friday Night: Partly cloudy. Breezy. Isolated showers in the evening. Haze through the night. Lows around 67 near the shore to around 51 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy. Scattered showers in the evening, then occasional showers after midnight. Lows around 66 near the shore to around 52 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 80 percent.

Friday: Mostly cloudy. Occasional showers early in the morning, then scattered showers in the late morning and afternoon. Highs around 80 near the shore to 64 to 69 at 4000 feet. North winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 80 percent.

Friday Night: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows around 65 near the shore to around 51 at 4000 feet. Northeast winds up to 10 mph. Chance of rain 70 percent.

Waikoloa

Tonight: Breezy. Mostly clear with isolated showers. Lows around 69 near the shore to 48 to 56 above 4000 feet. Southeast winds up to 25 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Breezy. Isolated showers early in the morning. Highs around 81 near the shore to 65 to 72 above 4000 feet. Northeast winds up to 25 mph. Chance of rain 20 percent.

Friday Night: Mostly clear. Isolated showers in the evening. Lows around 68 near the shore to 47 to 55 above 4000 feet. Northeast winds up to 15 mph shifting to the east after midnight. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Breezy to windy east-northeast trade winds will persist through next week, bringing periods of windward and mauka showers as bands of moisture move through. One of the many bands of moisture should be arriving tonight and persist through Friday morning.

Discussion

A ridge of high pressure far north of the state will maintain breezy to windy trades through next week. A front passing north of the state today has weakened the pressure gradient slightly and the trades have weakened a touch from yesterday. Bands of moisture will ride in with the trades from time to time and will be capable of producing brief downpours during the next several days. On visible satellite imagery this afternoon, there is one large band of moisture that looks to move in tonight and will likely produce some showery weather over windward and mauka areas through Friday morning.
Over the weekend, a stronger high will build north of the state and will likely strengthen the trade winds a notch with widespread windy trade winds expected especially on Sunday. Bands of moisture will continue to ride in with the trade winds and passing showers should be expected over windward and mauka areas with a few leeward showers as well. Winds could reach wind advisory thresholds for some of the windier areas but at this time, the trade wind inversion does not look very strong to produce really gusty conditions over leeward areas.
For next week, windy trades will persist across the state and may even strengthen even more by the middle of next week as another strong high builds far north of the state. Remnant moisture from the front passing far north of the state today should ride in with the strong trades around Monday of next week. The remnants of the front will likely bring higher amounts of moisture and could produce some moderate rainfall over windward and mauka areas. While there is good agreement between the GFS and the ECMWF on this band of moisture, there are subtle timing differences between the model with the GFS showing the moisture moving in Sunday night, while the ECMWF brings it in on Monday.

Aviation

Expect breezy to locally windy trades to continue for the next several days. Low ceilings and showers will favor windward and mauka locations. Brief periods of MVFR conditions are likely in showers, though VFR should prevail. Periods of lower visibility are also possible from Volcano around South Point to PHKO and over the leeward Big Island waters due to VOG emissions from Kilauea.
AIRMET TANGO remains in effect for moderate low-level turbulence below 080 over and downstream of island terrain. This AIRMET will likely be extended through the next couple of days due to the stronger trade winds.

Marine

Strong to near gale-force easterly trade winds will persist as strong high pressure remains over the Northeast Pacific. Seas will remain rough, with a combination of wind-driven seas and northwest swells moving through. A Small Craft Advisory due to a combination of strong winds and elevated seas is in effect through Saturday morning for all Hawaiian coastal waters and will likely be extended through the weekend.
Surf along exposed north and west-facing shores will slowly rise tonight as a northwest (310-330 degrees) swell builds into the coastal waters. This swell looks to peak Friday night and Saturday and may push surf heights above advisory levels. A downward trend is then expected in the northwest swell Sunday through early next week.
Surf along east-facing shores will remain rough through the weekend and into next week due to strong easterly trade winds.
Surf along south-facing shores will remain small, with mainly background south and southeast swells.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Saturday for all Hawaiian waters,

Data Courtesy of NOAA.gov