Photo Credit: Jason Weingardt

West Kaua’i

Today: Breezy. Mostly sunny with isolated showers. Highs around 86 near the shore to around 74 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 70 to 75 near the shore to around 61 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Friday: Breezy. Mostly sunny with isolated showers. Highs around 87 near the shore to around 75 above 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

South Kaua’i

Today: Breezy. Partly sunny with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs around 83. Northeast winds 15 to 25 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 68 to 74. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs around 84. East winds 15 to 25 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 73 to 80 in the valleys to around 64 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows 61 to 66 in the valleys to around 56 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Friday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 74 to 81 in the valleys to around 65 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

North Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 76 to 85. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 74. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with scattered showers. Highs 77 to 86. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

East Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 76 to 84. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 75. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with scattered showers. Highs 77 to 85. East winds 10 to 20 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Trade winds will remain at breezy to locally windy levels through early next week, peaking over the weekend. The trades may ease back to moderate levels around the middle of next week. Little change in the overall weather pattern is expected during the next 7 days, with bands of clouds and showers moving through the islands at times. The showers will favor windward and mauka areas, particularly at night and during the early morning hours, with a few showers occasionally reaching leeward communities.

Discussion

Currently at the surface, a 1031 mb high is centered around 1150 miles north-northeast of Honolulu, and is driving moderate to breezy trade winds across the island chain early this morning. Infrared satellite imagery shows mostly cloudy conditions over windward slopes and coasts, with partly cloudy skies in most leeward areas. Radar imagery shows scattered to numerous showers moving into windward locales, with some of these showers reaching leeward areas as well. Main short term focus revolves around the increasing trades during the next few days.
High pressure north-northeast of the islands will shift southwest and closer to the state during the next couple days, strengthening the pressure gradient across the island chain. The trade winds will strengthen to breezy levels today, and remain breezy through early next week. A drier more stable airmass will lower inversion heights down to around 5-6 kft this weekend, and this should allow the terrain to be particularly effective at accelerating the winds through the islands, with locally windy conditions expected. The trades may ease back to moderate levels around the middle of next week as the high to the distant northeast weakens.
As for the remaining weather details, typical trade wind weather is expected to continue during the next 7 days, with the exception of this weekend when a drier more stable airmass should reduce shower coverage statewide. Overall, bands of clouds and showers will periodically move through the islands throughout the forecast period, with showers favoring windward slopes and coasts, particularly at night and during the early morning hours. A few showers will reach leeward areas at times as well.

Aviation

A cell of high pressure sitting stagnant northeast of the state will bring moderate to locally breezy east northeasterly trades across the islands through the forecast period. Expect scattered showers to affect the windward coasts and slopes with isolated over leeward locations. Brief periods of MVFR ceilings and visibility may accompany any of the more robust shower activity.
AIRMET Tango is in effect for low level turbulence over and downwind of the terrain of all islands. This AIRMET will likely remain in place through the remainder of today due to the breezy trade winds.

Marine

Fresh to strong trades will persist into next week as the surface ridge strengthens to the north. Seas will quickly respond and become rough over the exposed waters. As a result, the Small Craft Advisory is now in effect for all Hawaiian waters through Sunday.
Surf along east facing shores will trend up through the weekend due to the strong winds.
Surf along south facing shores will remain small through Friday with mainly background southerly swell energy moving through. An upward trend is expected Friday night through the weekend as a long-period south-southeast swell arrives and begins to move through. This swell will continue through the first half of next week, with surf hovering above the summertime average each day beginning late Saturday.
Surf along north and west facing shores will remain near the summertime average through Saturday, then slightly trend up Sunday into next week as a small northwest swell arrives.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Sunday for all Hawaiian waters,

Data Courtesy of NOAA.gov