West Kaua’i

Today: Mostly sunny with isolated showers. Highs around 85 near the shore to around 75 above 3000 feet. East winds up to 15 mph shifting to the south in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 66 to 71 near the shore to around 57 above 3000 feet. East winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Wednesday: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 84 near the shore to around 74 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 83. East winds around 10 mph. Chance of rain 30 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 64 to 70. Northeast winds around 10 mph. Chance of rain 50 percent.

Wednesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82. East winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly sunny in the morning then becoming partly sunny. Scattered showers. Highs around 78 in the valleys to around 67 above 4000 feet. East winds up to 10 mph. Chance of rain 30 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 60 in the valleys to around 52 above 4000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs around 77 in the valleys to around 66 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

North Kaua’i

Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 78 to 84. East winds up to 15 mph. Chance of rain 30 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 60 to 69. Southeast winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 77 to 83. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 76 to 82. East winds up to 10 mph. Chance of rain 30 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 58 to 71. East winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 75 to 81. East winds 10 to 15 mph. Chance of rain 50 percent.

Synopsis

Moderate trades will prevail over the eastern islands through mid week, while lighter trades over the western end of the state allow for some leeward land and sea breezes. Relatively dry weather will persist through Wednesday, with a few showers affecting windward areas overnight into the early morning hours and developing over interior and leeward areas each afternoon. Moderate to locally breezy trade winds will return Wednesday night and Thursday, bringing a transition over to more typical trade wind weather. The trades will become breezy Thursday night through early next week, and the trade wind showers will likely increase in coverage and intensity as a disturbance aloft moves over the islands.

Discussion

Currently at the surface, a weak trough of low pressure is located around 325 miles northwest of Kauai, while a 1030 mb high is centered 1750 miles northeast of Honolulu. Moderate trade winds prevail over the eastern islands, while lighter trades remain over the western end of the state. Infrared satellite imagery shows a mix of high and low clouds resulting in partly to mostly cloudy conditions. Radar imagery shows isolated to scattered showers moving into windward areas, with mainly dry conditions in leeward locales. Main short term focus continues to revolve around trade wind trends and rain chances.
A weak trough of low pressure northwest of the islands will remain nearly stationary today, with little change expected in the overall wind forecast. Moderate trades will hold over the eastern end of the state, while lighter trades prevail over the western islands, allowing for leeward sea and land breezes. We should see the trades start to rebound from east to west tonight and Wednesday, as the trough west of the islands begins to shift slowly westward. Moderate to locally breezy trades should overspread the island chain Wednesday night and Thursday, with breezy conditions expected Thursday night through early next week as a pair of highs consolidate to the distant north.
As for the remaining weather details, relatively dry conditions should generally prevail across the island chain through Wednesday. Brief passing showers will be possible in windward areas overnight into the early morning hours, with a few showers developing over interior and leeward areas each afternoon. We should transition over to a more typical windward and mauka focused trade wind pattern Wednesday night and Thursday, with wetter trade wind conditions looking more likely to develop Friday through early next week as upper troughing sets up over the state and gradually closes off into an upper low in the vicinity of the islands.

Aviation

Hawaii remains wedged between surface high pressure far northeast of the state and a trough to the northwest. This pattern will allow light to moderate east to east-southeasterly flow to persist today.
Expect scattered showers along the windward portions of the islands and isolated showers elsewhere. Brief periods of MVFR ceilings and visibility may occur with this activity, though not expecting anything widespread. Land breezes are forecast to transition to sea breezes along portions of the leeward coasts by late this morning or early afternoon.
No AIRMETs are currently in effect.

Marine

Moderate to fresh east to east-southeast trade winds will persist today as high pressure remains far northeast of the area and a trough holds in place northwest of Kauai. Trade winds look to strengthen tonight into the moderate to locally strong range as high pressure will build far north of the state through the rest of the week. A Small Craft Advisory will likely initially be issued for the typical windy waters around the Big Island and Maui tonight and may be expanded to additional waters Friday or Saturday as the high pressure north of the state strengthens.
Tiny surf will persist along north facing shores through Friday, with a small pulse of northwest swell expected this weekend. A small long period south-southwest swell will peak today, and slowly ease Wednesday. Otherwise, small background level surf on south shores for the rest of the week. Choppy surf along east facing shores will decline over the next couple of days, then gradually increase as trade winds rebuild. Rough east shore surf will likely rise above seasonal average Friday into the weekend.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov