West Kaua’i

Tonight: Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 69 to 74 near the shore to around 62 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Monday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 83 to 90 near the shore to around 76 above 3000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Monday Night: Partly cloudy with isolated showers. Lows around 71 near the shore to around 61 above 3000 feet. Southeast winds up to 10 mph shifting to the east after midnight. Chance of rain 20 percent.

South Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows around 73. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Monday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 81 to 88. Southeast winds 10 to 15 mph. Chance of rain 50 percent.

Monday Night: Mostly cloudy with scattered showers. Lows around 72. East winds 10 to 15 mph. Chance of rain 40 percent.

Kaua’i Mountains

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows 64 to 70 in the valleys to around 59 above 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Monday: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 76 to 82 in the valleys to around 67 above 4000 feet. Southeast winds 10 to 15 mph. Chance of rain 70 percent.

Monday Night: Mostly cloudy with scattered showers. Lows 64 to 69 in the valleys to around 59 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

North Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 66 to 74. East winds 10 to 15 mph shifting to the southeast after midnight. Chance of rain 50 percent.

Monday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 85. Southeast winds up to 10 mph. Chance of rain 50 percent.

Monday Night: Mostly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 65 to 73. East winds 10 to 15 mph. Chance of rain 40 percent.

East Kaua’i

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows 65 to 76. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Monday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 74 to 86. Southeast winds 10 to 15 mph. Chance of rain 50 percent.

Monday Night: Mostly cloudy with scattered showers. Lows 64 to 76. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Light to moderate trades will persist over the next few days with moderate to locally breezy trades returning around mid week. Generally fair weather is expected throughout the week with batches of moisture riding in with the trade winds at times. Breezy to locally strong trades are expected for next weekend.

Discussion

This afternoon's satellite and radar imagery shows some scattered showers across the state, which are producing some light rainfall. Trade winds will continue to gradually weaken through Monday in response to a weak surface trough passing to our north. With light trades in place, land breezes will be possible for select areas tonight and sea breezes will be possible during the day on Monday. Shower activity could be slightly more active than your typical summer day on Monday due to a weak trough passing to our north and afternoon sea breeze development across select leeward areas. Also satellite imagery does show some high level clouds streaming over the western half of the state, which should linger into Monday.
By Tuesday or Wednesday, the trough should be away from our area with moderate trade winds returning across the state. Drier conditions with less cloud cover is expected for Tuesday and Wednesday.
For Thursday and Friday, we do have a weak upper level trough that will be moving through the island chain from the east, which could bring an uptick of shower coverage. But confidence remains low at this time, due to the lack of low level moisture.
Over the weekend, there is good agreement within the GFS and ECMWF ensembles for breezy to locally strong trade wind weather across the state. Stronger trades generally lead to more passing showers due to greater orographic lift. But any showers should remain on the lighter side due to stable conditions aloft.

Aviation

Moderate to locally breezy trade winds will gradually weaken into tomorrow as a broad surface trough moves overhead, weakening the local pressure gradient and veering the winds out of the east- southeast. With this lighter flow, sea breezes will begin to become more prevalent tomorrow afternoon, building clouds and showers over leeward and interior areas. Otherwise, passing showers will focus primarily over the usual windward and mountain areas, favoring the nighttime/early morning hours. Brief periods of MVFR conditions will remain possible with any showers but overall VFR conditions should prevail.
No AIRMETs are in effect this afternoon, but AIRMET Sierra for mountain obscuration may be needed overnight as shower coverage picks up across windward areas.

Marine

Moderate to locally breezy trades are expected to gradually decrease through Monday as a couple of troughs far to the north and northwest weaken the ridge to our north. Trades should veer slightly toward the east-southeast and weaken to gentle to moderate speeds as a result. Moderate to fresh trades could return as early as Tuesday as the troughs move away and high pressure rebuilds far north of the state.
Surf along south facing shores should see a small, long-period south swell slowly fill in through tonight, with surf peaking near or slightly above the summertime average late Monday through Tuesday. This swell will then gradually decline through the rest of the week. A smaller long-period south swell could move through toward the end of this week for a slight boost to south shore surf.
Surf along east shores will gradually decline over the next several days due to the trade winds weakening. Surf along north facing shores will remain tiny throughout next week.

HFO Watches/Warnings/Advisories

None.

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