Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Highs around 87 near the shore to around 75 above 3000 feet. East winds up to 15 mph.

Tonight: Mostly clear. Lows 68 to 73 near the shore to around 59 above 3000 feet. East winds around 10 mph.

Monday: Sunny. Highs around 87 near the shore to around 75 above 3000 feet. East winds 10 to 15 mph.

South Kaua’i

Today: Mostly sunny. Highs around 84. East winds 10 to 15 mph.

Tonight: Partly cloudy with isolated showers. Lows 66 to 72. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Monday: Mostly sunny. Breezy. Isolated showers in the morning. Highs around 84. East winds 15 to 20 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly sunny. Highs 74 to 81 in the valleys to around 65 above 4000 feet. East winds up to 15 mph.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 59 to 64 in the valleys to around 54 above 4000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Monday: Breezy. Mostly sunny with isolated showers. Highs 74 to 81 in the valleys to around 65 above 4000 feet. East winds 10 to 25 mph. Chance of rain 20 percent.

North Kaua’i

Today: Mostly sunny. Highs 77 to 86. East winds up to 15 mph.

Tonight: Partly cloudy with isolated showers. Lows 62 to 72. East winds 10 to 15 mph. Chance of rain 20 percent.

Monday: Mostly sunny. Isolated showers in the morning. Highs 77 to 86. East winds 10 to 15 mph. Chance of rain 20 percent.

East Kaua’i

Today: Mostly sunny. Highs 77 to 85. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows 60 to 73. East winds 10 to 15 mph. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs 77 to 85. East winds 10 to 15 mph. Chance of rain 20 percent.

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.

Data Courtesy of NOAA.gov