Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Mostly sunny with isolated showers. Highs around 85 near the shore to around 73 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows 68 to 73 near the shore to around 59 above 3000 feet. Northeast winds up to 15 mph.

Thursday: Mostly sunny. Breezy. Highs around 85 near the shore to around 73 above 3000 feet. East winds up to 20 mph.

South Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs around 82. East winds 10 to 15 mph. Chance of rain 50 percent.

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

Thursday: Breezy. Partly sunny with isolated showers. Highs around 82. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Partly sunny with scattered showers. Highs 72 to 79 in the valleys to around 63 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 59 to 64 in the valleys to around 54 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Thursday: Breezy. Partly sunny with scattered showers. Highs 72 to 79 in the valleys to around 63 above 4000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.

North Kaua’i

Today: Partly sunny with scattered showers. Highs 75 to 84. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows 62 to 72. Southeast winds up to 15 mph. Chance of rain 20 percent.

Thursday: Breezy. Partly sunny with isolated showers. Highs 75 to 84. East winds up to 20 mph. Chance of rain 20 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 75 to 83. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with isolated showers. Lows 60 to 73. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Thursday: Partly sunny with isolated showers. Highs 75 to 83. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

High pressure northeast of the state will maintain moderate to breezy trade winds through early next week. Showers will favor windward slopes and coasts, especially during the overnight and early morning hours. A trough aloft will move over the islands Friday through early next week, bringing an increase in trade wind shower coverage and intensity.

Discussion

Currently at the surface, a trough of low pressure is located around 775 miles west-northwest of Kauai, while a 1030 mb high is centered around 1550 miles northeast of Honolulu. Moderate to locally breezy trade winds prevail, strongest over the eastern end of the state. Infrared satellite imagery shows partly to mostly cloudy conditions across the state. Radar imagery shows scattered showers moving into windward slopes and coasts, with a few showers drifting leeward across the smaller islands. Main short term focus revolves around rain chances and trade wind trends.
High pressure will strengthen well northeast of the state during the next couple days, while the trough of low pressure west of the area lifts slowly northward. Wind speeds will trend up slightly, but remain at moderate to locally breezy levels. The trough will dampen out Friday through the weekend, while high pressure northeast of the state settles southwestward and closer to the island chain. This should give the trades another slight boost, with breezy trades then holding through early next week.
As for the remaining weather details, relatively dry trade wind weather should prevail during the next few days, with showers favoring windward slopes and coasts particularly at night and during the early morning hours. Troughing aloft will move over the islands Friday and linger through early next week, bringing an increase in trade wind shower coverage and intensity.

Aviation

Moderate to breezy easterly trades will continue through the 24-Hr forecast period and beyond, with clouds and showers favoring windward slopes and coasts. Expect periods of MVFR CIGs/VSBYs in clouds and showers moving through, particularly overnight through the early morning hours. Otherwise, VFR conditions will prevail.
AIRMET Sierra is in effect for mountain obscuration across windward sections of most islands this morning. Conditions should improve by the late morning hours.

Marine

Fresh to strong easterly trades will continue through the week as the surface ridge remains positioned north of the state. A Small Craft Advisory (SCA) remains in effect for a majority of the waters around Maui County and the Big Island through Thursday and additional waters around Oahu and Kauai may be needed for Thursday and Friday. Winds across the Kauai waters will fluctuate between east and east- southeast today due to a persistent surface trough to the west. A shift out of the east-northeast is expected beginning around Thursday as the trough weakens and drifts away from the region.
Surf along exposed south-facing shores will remain small throughout the next few days, due to a combination of background south- southwest and southeast swell energy. An upward trend is expected from Friday as a long run of south-southwest swell will maintain elevated surf as storm activity in the western half of the South Pacific remains well aimed towards Hawaii. Additional reinforcements will likely keep surf elevated through the first week of June.
Surf along exposed east-facing shores will remain small and choppy throughout the week as the trades persist.
Surf along north-facing shores will remain near the summertime average each day. Guidance depicts a small, long-period swell arriving early next week.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Thursday for Kaiwi Channel, Maui County Windward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov