Hilo

Tonight: Mostly cloudy with scattered showers. Lows 63 to 71 near the shore to 51 to 59 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers. Highs 79 to 87 near the shore to 66 to 73 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Saturday Night: Mostly cloudy with numerous showers. Lows 66 to 72 near the shore to 55 to 61 at 4000 feet. Northwest winds up to 10 mph in the evening becoming light. Chance of rain 70 percent.

Kona

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy after midnight. Haze through the night. Lows around 73 near the shore to 50 to 55 near 5000 feet. Light winds. Chance of rain 50 percent.

Saturday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Haze through the day. Highs 83 to 88 near the shore to around 70 near 5000 feet. Southwest winds up to 10 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Isolated showers in the evening. Haze through the night. Lows around 74 near the shore to 52 to 57 near 5000 feet. Light winds. Chance of rain 20 percent.

Waimea

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 62 to 70 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Saturday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 80 near the shore to 68 to 79 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Saturday Night: Mostly cloudy with scattered showers. Lows 64 to 72 near the shore to 57 to 64 near 3000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Kohala

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 62 to 70 near the shore to 55 to 62 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Saturday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 80 near the shore to 68 to 79 near 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Saturday Night: Mostly cloudy with scattered showers. Lows 64 to 72 near the shore to 57 to 64 near 3000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

South Big Island

Tonight: Partly cloudy. Scattered showers in the evening. Haze through the night. Lows around 74 near the shore to around 56 near 5000 feet. East winds up to 15 mph in the evening becoming light. Chance of rain 40 percent.

Saturday: Mostly sunny. Haze through the day. Isolated showers in the afternoon. Highs 83 to 88 near the shore to around 70 near 5000 feet. Southeast winds up to 10 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Isolated showers in the evening. Haze through the night. Lows around 76 near the shore to around 58 near 5000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Puna

Tonight: Mostly cloudy with scattered showers. Lows 63 to 71 near the shore to 51 to 59 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers. Highs 79 to 87 near the shore to 66 to 73 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Saturday Night: Mostly cloudy with numerous showers. Lows 66 to 72 near the shore to 55 to 61 at 4000 feet. Northwest winds up to 10 mph in the evening becoming light. Chance of rain 70 percent.

Waikoloa

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 73 near the shore to 51 to 56 above 4000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Saturday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 84 to 91 near the shore to 67 to 74 above 4000 feet. North winds up to 15 mph. Chance of rain 20 percent.

Saturday Night: Partly cloudy. Isolated showers in the evening. Lows around 76 near the shore to 53 to 58 above 4000 feet. Southeast winds up to 10 mph. Gusts up to 30 mph in the evening. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Trades will ease to gentle to moderate strength into the weekend in response to an approaching weak surface trough from the east, An increase in mainly windward and mauka rainfall is possible along this dissipating feature late Saturday into Monday. Trades will strengthen again around Tuesday or Wednesday.

Discussion

Trades will ease to gentle to moderate strength into the weekend in response to an approaching weak surface trough from the east. While this trough is progged to dissipate upon reaching the islands, the associated moisture escorted by the trough may be just enough to increase humidity levels and prompt a greater chance for windward showers across Big Island and possibly Maui County during the latter half of the weekend, and then further north into Oahu and Kauai by early next week. Otherwise, shower activity will be limited and primarily across windward and mauka areas, with exception to the South Kona slopes during the afternoon periods.
Latest model guidance continues to depict trades strengthening back to moderate to locally breezy by Tuesday or Wednesday of next week, however, with uncertainty persisting with regards to tropical development south of Hawaii, confidence of the forecast remains low. That said, the likeliness of breezy trades within drier conditions is high.

Aviation

Moderate trades will ease slightly to gentle to moderate trades Saturday and Sunday. A relatively stable and dry pattern will hold through in Saturday. Expect predominately VFR conditions across the Hawaiian Islands, however, brief periods of isolated showers across windward and mountain areas remain possible. A weakening trough moving from east to west may possibly increase chance of low level clouds and precipitation and thus MVFR conditions first for the windward areas the Big Island Saturday afternoon then for the rest of the state by Saturday night into Sunday.
There currently are no AIRMETs in effect.

Marine

High pressure north of the area has weakened today allowing for moderate to locally fresh trades. The high will further weaken this weekend, easing wind speeds to gentle to fresh. Moderate to strong trades then return next week as high pressure restrengthens and a tropical disturbance tracks south of the state.
Small background S swell keeps surf from going flat along S shores through early next week. A storm force low E of New Zealand is producing seas up to 40 feet per JSON satellite observations indicating undersimulation of winds by the model guidance. Confidence is therefore increased that this low will generate a moderate long period S swell that approaches or exceeds the High Surf Advisory threshold during its peak.
Choppy surf along E facing shores will trend down into the weekend as winds ease locally and upstream. Flat to tiny surf expected along N facing shores through the forecast period.
Peak afternoon high tides combined with elevated water levels are running about half a foot higher than predicted. This trend will continue through this afternoon and could lead to minor flooding along the shoreline and in low lying coastal areas of Maui County and the Big Island. Water levels then lower for the weekend.

Fire weather

Dry and stable conditions will persist through Saturday, and locally breezy trade winds will ease slightly. A shallow area of moisture moving in from the east should bring an increase in humidity late Saturday into Monday, further decreasing fire weather concerns. Trade winds are expected to restrengthen Tuesday or Wednesday, with developing dry conditions reestablishing, may result in elevated fire weather concerns

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov