Hilo

Today: Mostly sunny with isolated showers. Highs around 84 near the shore to 69 to 74 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 68 near the shore to around 54 at 4000 feet. Northeast winds around 10 mph. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs around 84 near the shore to 69 to 74 at 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 82 to 87 near the shore to around 69 near 5000 feet. West winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows 69 to 75 near the shore to around 55 near 5000 feet. Light winds.

Monday: Mostly sunny. Isolated showers in the afternoon. Highs 82 to 87 near the shore to around 69 near 5000 feet. West winds around 10 mph. Chance of rain 20 percent.

Waimea

Today: Mostly sunny. Breezy. Isolated showers in the morning. Highs around 82 near the shore to 69 to 79 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows around 68 near the shore to 56 to 62 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Monday: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 82 near the shore to 69 to 79 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Kohala

Today: Mostly sunny. Breezy. Isolated showers in the morning. Highs around 82 near the shore to 69 to 79 near 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows around 68 near the shore to 56 to 62 near 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Monday: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 82 near the shore to 69 to 79 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny. Breezy. Highs around 86 near the shore to around 73 near 5000 feet. East winds up to 20 mph.

Tonight: Mostly clear. Breezy. Lows around 70 near the shore to around 53 near 5000 feet. East winds 10 to 20 mph.

Monday: Sunny and breezy. Highs around 86 near the shore to around 73 near 5000 feet. East winds 10 to 25 mph.

Puna

Today: Mostly sunny with isolated showers. Highs around 84 near the shore to 69 to 74 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 68 near the shore to around 54 at 4000 feet. Northeast winds around 10 mph. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs around 84 near the shore to 69 to 74 at 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny. Highs around 86 near the shore to 70 to 76 above 4000 feet. Northeast winds up to 15 mph.

Tonight: Mostly clear. Lows 70 to 75 near the shore to 51 to 58 above 4000 feet. East winds 10 to 15 mph.

Monday: Sunny. Highs around 86 near the shore to 70 to 76 above 4000 feet. North winds 10 to 15 mph.

Detailed Forecast

Synopsis

Moderate to breezy trade winds will continue to strengthen through the middle of next week as high pressure slowly rebounds to our north. Scant trade showers will favor windward shores and slopes.

Discussion

Moderate trade winds continued overnight, with locally breezy conditions noted in the eastern channels, in spite of a weakened ridge to our north. Latest soundings showed a dry and stable airmass, thanks to strong ridging aloft, with less than an inch of PW and positive lifted index values. Steep inversions near 4000 feet worked to limit cloud development and rainfall, especially away from windward areas. Radar shows almost no shower activity within range.
Models show the ridge to our north will rebound through the forecast period as a hampering mid-latitude trough farther to the north lifts out. Trades will continue to strengthen across local waters as upper ridging shifts north and east of the islands through early next week. Expect a trade wind weather pattern through the forecast period, with clouds and showers favoring windward areas. Total rainfall will be light.

Aviation

Breezy trades will continue to gradually increase through the rest of today. With high pressure and dry air in place over the region, SHRA activity will be limited. A strong inversion will keep low cigs allowing for periods of MVFR conds. Otherwise, VFR conds should prevail.
No AIRMETs currently in effect.

Marine

Moderate to locally strong easterly trades will increase into the fresh to strong range today and continue through much of the week as the surface ridge strengthens to the north. This may lead to the Small Craft Advisory expanding to the Kaiwi Channel and Maui County Windward waters by Monday. Guidance suggests a potential weakness forming in the ridge northwest of the state next weekend, which could lead to moderate to fresh east-southeast trades.
Surf along south-facing shores will remain up through the week due to an active pattern within our swell window near New Zealand. Overlapping, long-period, south to south-southwest swells are expected, with the next one beginning to fill in early this morning (peak energy centered within the 18-22 second bands at the buoys). Guidance shows this swell peaking late tonight through Monday. A downward trend is anticipated Tuesday through midweek, with mainly a mix of the fading south-southwest swell and a small, medium-period southeast swell. A fresh long-period south swell is expected to arrive Thursday night into Friday, then peak late Friday into Saturday.
Surf along north-facing shores will remain up slightly through the first half of the week as small north to north-northwest pulses move through. The next north pulse should fill in late Monday, with a small north-northwest swell arriving Tuesday into midweek. A return to summertime/flat conditions is likely later this week through next weekend.
Surf along east-facing shores should trend up later this week as the trades become established locally and upstream across the eastern Pacific.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Monday for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai West, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.
Small Craft Advisory until 6 AM HST Tuesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov