Hilo

Tonight: Mostly cloudy with isolated light showers. Lows 61 to 68 near the shore to 49 to 55 at 4000 feet. Light winds. Chance of rain 20 percent.

Saturday: Partly sunny. Isolated light showers in the morning, then scattered showers in the afternoon. Highs 76 to 82 near the shore to 62 to 68 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 40 percent.

Saturday Night: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 61 to 69 near the shore to 48 to 54 at 4000 feet. Light winds. Chance of rain 40 percent.

Kona

Tonight: Mostly cloudy. Lows around 70 near the shore to 44 to 50 near 5000 feet. Light winds.

Saturday: Partly sunny. Isolated light showers in the late morning and afternoon. Highs 81 to 86 near the shore to around 67 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Saturday Night: Mostly cloudy with isolated light showers. Lows around 70 near the shore to 43 to 48 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Mostly cloudy with isolated light showers. Lows 62 to 70 near the shore to 51 to 58 near 3000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Saturday: Partly sunny with isolated light showers. Highs around 77 near the shore to 67 to 76 near 3000 feet. Northwest winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Saturday Night: Partly cloudy with isolated light showers. Lows 62 to 70 near the shore to 50 to 58 near 3000 feet. Light winds. Chance of rain 20 percent.

Kohala

Tonight: Mostly cloudy with isolated light showers. Lows 62 to 70 near the shore to 51 to 58 near 3000 feet. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Saturday: Partly sunny with isolated light showers. Highs around 77 near the shore to 67 to 76 near 3000 feet. Northwest winds up to 10 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Saturday Night: Partly cloudy with isolated light showers. Lows 62 to 70 near the shore to 50 to 58 near 3000 feet. Light winds. Chance of rain 20 percent.

South Big Island

Tonight: Mostly cloudy. Lows around 71 near the shore to around 49 near 5000 feet. Northeast winds up to 15 mph.

Saturday: Partly sunny. Isolated showers in the late morning and afternoon. Highs around 83 near the shore to around 66 near 5000 feet. Southeast winds up to 10 mph shifting to the south in the afternoon. Chance of rain 20 percent.

Saturday Night: Mostly cloudy with isolated light showers. Lows around 70 near the shore to around 47 near 5000 feet. Light winds. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with isolated light showers. Lows 61 to 68 near the shore to 49 to 55 at 4000 feet. Light winds. Chance of rain 20 percent.

Saturday: Partly sunny. Isolated light showers in the morning, then scattered showers in the afternoon. Highs 76 to 82 near the shore to 62 to 68 at 4000 feet. Southeast winds up to 10 mph. Chance of rain 40 percent.

Saturday Night: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 61 to 69 near the shore to 48 to 54 at 4000 feet. Light winds. Chance of rain 40 percent.

Waikoloa

Tonight: Mostly cloudy. Lows around 70 near the shore to 47 to 52 above 4000 feet. Light winds.

Saturday: Partly sunny. Isolated light showers in the late morning and afternoon. Highs 81 to 87 near the shore to 64 to 69 above 4000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Lows around 69 near the shore to around 48 above 4000 feet. Light winds.

Detailed Forecast

Synopsis

Gentle trade winds will weaken overnight, becoming light and variable Saturday and Sunday allowing for overnight land breezes and afternoon sea breezes to develop. A dry and stable airmass will remain over the state, limiting rainfall. A weak shallow front may move across the western end of the island chain Sunday night into Monday, bringing only modest showers and gentle northerly winds. Light to moderate trades may return by the middle of next week.

Discussion

Currently, satellite imagery shows high clouds continuing to fill in across the state from the west as a weak jet streak develops aloft, along with some low clouds developing across island interiors with sea breeze activity. Radar activity is rather quite this evening with only few light isolated showers moving over windward areas over Maui and the Big Island. An area of clouds and showers just east of the Big Island will keep this trend through the evening. As winds ease overnight and early morning, expect a land breeze to form and pushing low level clouds offshore.
Saturday and most of the day Sunday will remain on the drier side as the dry and stable airmass lingers over the state. Expect light and variable winds through the weekend which will allow for land breezes to develop overnight and early morning. Clouds will begin to develop inland and upslope as sea breezes during the day. Dew points will remain in the lower to mid 60s across most locations, allowing overnight lows to drop to a few degrees below normal through the weekend and keeping afternoons pleasant with lower relative humidity values. In addition, the high clouds associated with the jet streak aloft will begin to thin out across the western half of the state Saturday afternoon into evening and then across the eastern end by Monday as the jet streak gradually shifts south and east of the state.
The GFS and ECMWF have come into better agreement on bringing a weak cold front to Kauai's doorstep Sunday evening, and then having it dissipate as it gradually moves towards Oahu and Maui County on Monday and Tuesday. Impacts look to be minimal with gentle northerly winds moving in behind the front, along with the potential for a slight uptick in shower activity for the western end of the state. Low level tropical moisture moving in east of windward Big Island will bring a little bump in shower activity for south and east facing slopes of the eastern half of the state Saturday night into Sunday. Despite some model discrepancies Tuesday and beyond, mid level ridging will build in from the west and surface high pressure will set up northeast of the state by Thursday and bring a return to light to moderate easterly trades heading into the latter part of the week.

Aviation

Light winds with sea/land breezes are expected through tomorrow. Some light SHRA and isol brief MVFR conds are possible in the evenings primarily along windward and mauka locations. Otherwise, VFR conds should prevail.
No AIRMETS are in effect. However a subtropical jet will move through the state the next several days, which could produce some light to moderate turb tomorrow between FL270 and FL380, and thus we may need AIRMET Tango if and when conds warrant.

Marine

Weak high pressure will hold just north of Hawaiian offshore waters through most of the weekend. A weak front will approach the far western waters Sunday night then dissipate over Oahu on Monday. Winds are expected to remain light and variable through the weekend and into Monday. Light to moderate trade winds will return later next week when high pressure rebuilds to the north of the state.
The current, small, medium period, NNE (360-020) swell impacting the Islands will be at its peak Saturday afternoon. A second moderate, medium period pulse from the same source will fill in Saturday and provide reinforcement. Lastly, an overlapping NW swell (320 degrees) will build on Saturday and peak during the day Sunday. Surf along north and west facing beaches will remain small on Saturday, approach High Surf Advisory (HSA) criteria on Sunday, then subside early next week. A Marine Weather Statement is in effect for harbor surges, particularly at Hilo and Kahului harbor, generated by the two more northerly swells.
Surf along east facing shores will become more elevated Saturday into Sunday as the more northerly swells peak and shift more easterly, wrapping into exposed areas.

Fire weather

KBDI values remain high across the state, and an overall dry weather pattern is expected through at least Sunday over most islands. With dry air moving overhead, relative humidity values will have the potential to drop below the critical 45% threshold during the late morning and afternoon hours. However, lighter winds will mitigate fire weather concerns.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov