Photo Credit: Jason Weingardt

West Kaua’i

Today: Breezy. Mostly cloudy with scattered showers. Highs around 83 near the shore to around 71 above 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows around 69 near the shore to around 62 above 3000 feet. East winds 10 to 25 mph decreasing to up to 20 mph after midnight. Chance of rain 50 percent.

Thursday: Mostly cloudy in the morning then becoming mostly sunny. Breezy. Isolated showers. Highs around 83 near the shore to around 71 above 3000 feet. East winds up to 25 mph. Chance of rain 20 percent.

South Kaua’i

Today: Mostly cloudy. Breezy. Numerous showers early in the morning, then scattered showers in the late morning and afternoon. Highs around 80. East winds 15 to 25 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 69. East winds 15 to 25 mph. Chance of rain 50 percent.

Thursday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 80. East winds 15 to 25 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Showers early in the morning, then scattered showers in the late morning and afternoon. Highs 70 to 77 in the valleys to around 61 above 4000 feet. East winds 10 to 20 mph. Chance of rain 90 percent.

Tonight: Cloudy and breezy. Numerous showers in the evening, then showers after midnight. Lows 62 to 67 in the valleys to around 60 above 4000 feet. East winds 10 to 20 mph. Chance of rain 90 percent.

Thursday: Cloudy and breezy. Showers in the morning, then scattered showers in the afternoon. Highs 70 to 77 in the valleys to around 61 above 4000 feet. East winds 10 to 25 mph. Chance of rain 80 percent.

North Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 73 to 82. East winds up to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 63 to 70. East winds 10 to 20 mph decreasing to up to 15 mph after midnight. Chance of rain 50 percent.

Thursday: Breezy. Mostly cloudy with scattered showers. Highs 73 to 82. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Gusts up to 40 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly cloudy. Breezy. Showers early in the morning, then scattered showers in the late morning and afternoon. Highs 73 to 81. East winds 10 to 20 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 64 to 71. East winds 10 to 15 mph. Chance of rain 70 percent.

Thursday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 73 to 81. East winds 10 to 20 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Moist east to southeast trades combined with an upper disturbance to the west will keep the chances up for periods of showery conditions across Kauai County and the southeast facing slopes of the Kau and Puna Districts of the Big Island this morning. Elsewhere, showers will favor the typical windward and mountain areas. Drier air and strong easterly trade winds are expected through the second half of the week as low pressure to the west drifts away from the area. A wetter trade wind pattern is possible this weekend as an upper disturbance settles southward into the area.

Discussion

Guidance remains in good agreement and shows the axis of deep tropical moisture and the upper low that brought the heavy rainfall to portions of the state beginning to drift away from the area today. Mid-level ridging nosing westward accompanied by plenty of mid-level dry air will translate to a drying trend from east to west through the day. Morning upper air sounding at Lihue reflected this mid-level dry air with a temperature inversion around 7000-8000 ft. The east-southeast low-level flow will back to a more typical easterly trade wind direction tonight into Thursday, with wind speeds potentially reaching the advisory level as strong high pressure sets up to the north-northeast.
For the upcoming weekend, guidance shows an upper trough moving in from the northeast. Lowering upper heights and increasing instability associated with this upper feature could support increasing trade wind shower coverage. Although the bulk of the showers will favor windward areas, the brisk trades will manage to carry some into leeward areas, especially through the overnight and early morning periods this weekend.

Aviation

A breezy wet trade wind pattern will last through the TAF period. Expect MVFR conditions from time to time across windward areas as increased moisture, embedded within trade flow, pushes across the state. Breezy trade winds will necessitate continuing AIRMET Tango, for low-level moderate turbulence, across Maui, Molokai, and Oahu, through today. This may be expanded later to include the whole state if conditions warrant.
The potential for light icing continues in a layer between 150/FL250 as a band of mid and upper level moisture lingers across the state. This should be mostly focused over the western islands.

Marine

Strong high pressure northeast of the state will generate strong to near-gale force trade winds across Hawaiian waters through the upcoming weekend. A Small Craft Advisory (SCA) remains in effect for most waters due to a combination of winds and rough seas through at least Friday. The SCA will likely be extended through the weekend as strong trades winds persist. Surface troughing and an upper low west of the state will continue to generate showers with locally heavy rainfall into Thursday.
Surf along east facing shores will remain rough through the week due to persistent strong trade winds over and upstream of the Hawaiian Islands. The High Surf Advisory (HSA) is now in effect for east facing shores, through Thursday afternoon. The HSA will likely be extended in time as east facing shore surf will likely hold at or near low-end advisory levels through the weekend.
A series of small, medium to long-period northwest (310-330 degrees) swells will move through local waters through the weekend. Expect surf heights along north and west facing shores to remain well below the seasonal average through Sunday. South shore surf will also remain small through the weekend. A small, long-period south swell (170 degrees) could provide a small bump up in south shore surf for Sunday into early next week.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Thursday for Olomana, Maui Windward West, Kauai East, East Honolulu, Koolau Windward, Molokai Windward, Molokai Southeast, Windward Haleakala, Kipahulu, Big Island Southeast, Big Island East, Big Island North.
Small Craft Advisory until 6 PM HST Friday for all Hawaiian waters,

Data Courtesy of NOAA.gov