Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Highs around 88 near the shore to around 76 above 3000 feet. North winds up to 10 mph shifting to the southwest in the afternoon.

Tonight: Partly cloudy with scattered showers. Lows 69 to 74 near the shore to around 60 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Friday: Mostly sunny. Scattered showers in the morning. Highs around 88 near the shore to around 76 above 3000 feet. Northwest winds up to 10 mph shifting to the southwest in the afternoon. Chance of rain 50 percent.

South Kaua’i

Today: Partly sunny. Isolated showers in the morning. Highs around 85. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 67 to 73. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Partly sunny. Scattered showers in the morning. Highs around 85. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 75 to 82 in the valleys to around 66 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with numerous showers. Lows 60 to 65 in the valleys to around 55 above 4000 feet. East winds up to 10 mph. Chance of rain 60 percent.

Friday: Cloudy with numerous showers in the morning, then partly sunny with isolated showers in the afternoon. Highs 75 to 82 in the valleys to around 66 above 4000 feet. East winds up to 15 mph. Chance of rain 60 percent.

North Kaua’i

Today: Partly sunny with isolated showers. Highs 78 to 87. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 73. East winds up to 10 mph. Chance of rain 50 percent.

Friday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 87. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny with isolated showers. Highs 78 to 86. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy with numerous showers. Lows 61 to 75. Northeast winds 10 to 15 mph shifting to the north after midnight. Chance of rain 60 percent.

Friday: Mostly cloudy. Numerous showers in the morning, then isolated showers in the afternoon. Highs 78 to 86. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 60 percent.

Detailed Forecast

Synopsis

Trade winds will slightly ease today through Saturday, then return to breezy levels Sunday through early next week. Showers will favor windward and mauka areas, mostly overnight through the morning periods.

Discussion

Guidance shows the mid- to upper-level ridge in place weakening later today through Friday as a weak upper low settles north of Kauai and a mid-level trough approaches from the east. The surface ridge will respond by weakening, resulting in the trades easing to light to moderate levels. Upper-level height falls combined with increasing low-level moisture and a higher inversion could lead to better windward and mauka shower coverage, especially over the weekend as the mid-level trough moves through from east to west. Additionally, a few light showers can't be ruled out over dry leeward areas during the afternoons where localized sea breezes develop.
Trades will return to breezy levels by the end of the weekend, which should persist through early next week as surface high pressure builds north of the area.

Aviation

Trade winds will weaken slightly today, increasing the chance for localized sea breezes to develop. Clouds and showers will generally favor windward and mountain areas across the island chain, although sea breezes may allow clouds and showers to develop across a few leeward and interior areas this afternoon. VFR conditions will prevail with brief periods of MVFR possible in the overnight to early morning hours along windward areas.
AIRMET Tango remains in effect for moderate turbulence over and immediately south through west of all island mountains, but may be cancelled later today as the trade winds weaken slightly.

Marine

A weakening surface ridge to the north of the state will ease the pressure gradient around the islands through the end of the week. Trade winds speed look to trend towards gentle to moderate speeds through the weekend. A potential slight increase of the trade winds may push it back to locally strong levels in the typical windy areas of Maui County and the Big Island by early next week. For now, the Small Craft Advisory (SCA) has been cancelled and looks to remain that way through the weekend.
The fading south swell will keep surf from going flat today along south facing shores. A new small south- southwest swell is expected to build late tonight. The dominant wave period looks to be 14 to 16 seconds as it moves in, peaks late Friday, and holds through Saturday near the summertime average before slowly easing Sunday.
A few tiny pulses from the north-northwest are expected today and will likely keep the surf from going completely flat along north facing shores through the weekend. Short-period wind waves generated by the trade winds will gradually decline over the next several days as the trades ease. Small, long-period east swells from increased east Pacific tropical cyclone activity may arrive over the weekend, leading to a subtle increase in surf heights.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov