Photo Credit: James Grenz

Hilo

Today: Mostly cloudy with numerous showers. Highs around 84 near the shore to 69 to 74 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows around 68 near the shore to around 54 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 83 near the shore to 68 to 73 at 4000 feet. East winds 10 to 15 mph. Chance of rain 70 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 74 near the shore to around 55 near 5000 feet. Light winds.

Tuesday: Sunny. Isolated showers in the afternoon. Highs 81 to 86 near the shore to around 68 near 5000 feet. South winds up to 10 mph shifting to the northwest around 10 mph in the afternoon. Chance of rain 20 percent.

Waimea

Today: Breezy. Partly sunny with scattered showers. Highs around 82 near the shore to 69 to 79 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 56 to 62 near 3000 feet. East winds up to 25 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 81 near the shore to 68 to 78 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Partly sunny with scattered showers. Highs around 82 near the shore to 69 to 79 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68 near the shore to 56 to 62 near 3000 feet. East winds up to 25 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 81 near the shore to 68 to 78 near 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

South Big Island

Today: Mostly sunny in the morning then becoming partly sunny. Windy. Highs around 86 near the shore to around 73 near 5000 feet. East winds up to 30 mph.

Tonight: Partly cloudy. Windy. Lows around 70 near the shore to around 53 near 5000 feet. East winds up to 30 mph becoming 10 to 25 mph after midnight.

Tuesday: Sunny and breezy. Highs around 85 near the shore to around 72 near 5000 feet. East winds 10 to 20 mph.

Puna

Today: Mostly cloudy with numerous showers. Highs around 84 near the shore to 69 to 74 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows around 68 near the shore to around 54 at 4000 feet. Northwest winds up to 15 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 83 near the shore to 68 to 73 at 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Waikoloa

Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs around 86 near the shore to 70 to 76 above 4000 feet. Northeast winds up to 25 mph.

Tonight: Partly cloudy. Breezy. Lows around 72 near the shore to 51 to 58 above 4000 feet. Southeast winds up to 25 mph decreasing to up to 15 mph after midnight.

Tuesday: Sunny. Highs around 85 near the shore to 69 to 75 above 4000 feet. North winds up to 10 mph.

Detailed Forecast

Synopsis

Breezy trade winds will continue this week with high pressure slowly tracking eastward. Scant trade showers will favor windward shores and slopes.

Discussion

High pressure to our north continues to rebound as troughing farther to the north lifts out. The pressure gradient remains steep enough to support breezy trade winds across local waters this morning. Ridging aloft keeps our airmass dry and stable, with overnight soundings showing strong inversions near 6300 feet along with PW around 1.2 inches and positive lifted index values. Satellite loop shows patchy broken to overcast low clouds across windward and mauka areas of Oahu and the islands of Maui County, with only scattered low clouds noted on Kauai. Cloud cover decreased significantly across the Big Island overnight, leaving patchy broken low clouds across windward shorelines and lower slopes. Radar shows only isolated light showers associated with this cloud cover.
Models show high pressure to our north will track eastward through the week, with a low shifting the high a bit southward by next weekend. Our weather pattern will change very little through the period, with minor fluctuations in wind speeds and mostly dry and stable conditions continuing. A few windward clouds and showers will occur at times, but no significant rainfall is expected through the week.

Aviation

High pressure and dry air is in place over the region. This should limit any SHRA activity to windward and mauka locations if at all. A strong inversion will keep cigs low allowing for periods of MVFR conds. VFR conds should reign supreme otherwise. Locally breezy trades will continue slightly increasing through the rest of today.
While conds are generally VFR across the area, AIRMET Sierra for mtn obsc may be needed.
AIRMET Tango is in effect for mod turb S and W of island terrain.

Marine

Fresh to strong easterly trades will continue through much of the week, as the surface ridge strengthens to the north. 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 hold around the advisory level today due to a long-period south-southwest swell moving through. No signs of any downward trend at the offshore buoys early this morning with the peak energy holding steady in the 15 to 17 second bands. As a result, the advisory may need to be extended through tonight. 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 similar 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 today, 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 this evening 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 PM 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