West Kaua’i

Tonight: Partly cloudy. Isolated showers after midnight. Lows around 68 near the shore to around 58 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs 81 to 87 near the shore to around 73 above 3000 feet. Light winds becoming southeast up to 10 mph in the afternoon. Chance of rain 20 percent.

Sunday Night: Partly cloudy with isolated showers. Lows around 68 near the shore to around 58 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 69. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs 76 to 86. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Sunday Night: Mostly cloudy with scattered showers. Lows around 69. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 60 to 67 in the valleys to around 56 above 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

Sunday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 72 to 79 in the valleys to around 64 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 70 percent.

Sunday Night: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 61 to 67 in the valleys to around 56 above 4000 feet. East winds up to 10 mph. Chance of rain 70 percent.

North Kaua’i

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 62 to 71. Southeast winds up to 10 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs 74 to 82. East winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 50 percent.

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

East Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 62 to 73. North winds up to 10 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs 73 to 83. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Sunday Night: Mostly cloudy with scattered showers. Lows 62 to 72. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

High pressure north of the islands will bring moderate to breezy trade winds through Monday. Wind speeds will weaken from Tuesday through Thursday as a weakening surface pressure trough moves into the state. Southeast winds are expected late next week, with a chance that trade winds return next weekend as high pressure at the surface strengthens to our north.

Discussion

Radar and satellite show mostly cloudy skies and scattered showers across most windward and many mauka areas, along with the Kona region of the Big Island, this afternoon. Very few showers have made it to leeward areas, but a good amount of cloud cover has moved in from time to time. Winds were generally out of the northeast at 10 to 20 mph with a few higher gusts, but some leeward areas had west winds coming in off the ocean. These showers will decrease in the Kona region this evening, but otherwise should continue into the night.
With the upper low to our northeast finally moving away, upper level ridging will be able to strengthen. This will keep moderate to occasionally breezy trade winds with us through Monday as surface high pressure systems to our NE and NW move east across the Pacific. A weak trough (dying cold front) will move toward the area Monday, and pressure falls associated with its approach will veer winds to southeasterly Monday night. Light north to northeast winds behind the trough are expected to develop over western islands Wednesday, perhaps reaching as far east as Maui Wednesday night. With light winds Tuesday through Thursday, expect a few more clouds than normal over leeward areas, and perhaps a brief shower.
Winds will then return to southeasterly Thursday and remain that way into next weekend. PW values will be relatively low throughout the next week. The only day of values noticeably above 1″ will be Wednesday, when convergence from the surface trough will peak. Trades may return next weekend.

Aviation

Moderate to breezy trades will persist today, with clouds and brief showers favoring windward sites. Expect periods of MVFR conditions within windward showers, otherwise widespread VFR is expected.
No AIRMETS are in effect.

Marine

Trades steadily weaken, becoming light to variable by the middle of next week as a decaying front approaches from the west.
Existing small WNW swell will gradually fade through the weekend. Another slightly smaller NW swell is anticipated early next week in maintenance of elevated surf along N and W shores. Guidance then indicates another long period NW (320) swell arriving late next week. This swell will be generated by a developing low near Japan that is forecast to lift NE toward the Kuril Islands this weekend. Surf along S shores trends up this weekend as a long period SSW pulse arrives. This swell will peak late Sunday into Monday. As trades steadily weaken, wind waves and trade wind swell will follow with diminishing surf expected along E facing shores during the next several days.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov