Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Breezy. Highs around 88 near the shore to around 75 above 3000 feet. East winds up to 20 mph.

Tonight: Partly cloudy. Isolated showers after midnight. Lows around 71 near the shore to around 60 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Highs around 88 near the shore to around 74 above 3000 feet. East winds up to 15 mph.

South Kaua’i

Today: Breezy. Mostly sunny with isolated showers. Highs 79 to 86. Northeast winds 15 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows around 72. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Friday: Breezy. Mostly sunny with isolated showers. Highs 79 to 87. East winds 10 to 20 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Breezy. Partly sunny with scattered showers. Highs 75 to 85 in the valleys to 63 to 68 above 4000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 63 to 69 in the valleys to around 59 above 4000 feet. East winds 10 to 20 mph decreasing to up to 15 mph after midnight. Chance of rain 50 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 75 to 85 in the valleys to 63 to 68 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

North Kaua’i

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 88. East winds up to 20 mph. Chance of rain 30 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 64 to 73. East winds 10 to 15 mph. Chance of rain 40 percent.

Friday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 88. East winds up to 15 mph. Chance of rain 30 percent.

East Kaua’i

Today: Mostly sunny with isolated showers. Highs 74 to 84. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 65 to 75. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Mostly sunny with isolated showers. Highs 74 to 84. East winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A high pressure ridge will linger north of the Hawaiian Islands into next week producing moderate to breezy trade winds. Weak upper level troughing will keep brief periods of windward showers in the forecast favoring windward and mountain areas with drier conditions over leeward locations. Clouds and showers will develop along the Kona slopes of the Big Island each afternoon and evening.

Discussion

A fairly typical moderate to breezy trade wind weather pattern will continue as a high pressure ridge remains locked in place north of the Hawaiian Islands into next week. Weak upper level troughing will keep the trade wind temperature inversion heights between 5,000 to 7,000 feet for much of the forecast period. Trade wind inversion heights at this level will keep brief periods of shower activity in the forecast, mainly over windward and mountain areas as the trade winds lift the moisture over the windward mountain peaks. Shower activity in these windward mountain areas will trend higher in the overnight to early morning hours. Drier conditions are forecast over leeward locations. High level cirrus clouds will move over the state into the weekend, enhancing sunrise and sunset colors.
Not much day to day changes in the weather forecast over the next seven days. A slight increasing trend in the easterly trade wind speeds may develop by next week Wednesday.

Aviation

Moderate to breezy trade winds will persist over the next couple of days. SHRA and low cigs will favor windward and mauka areas bringing brief periods of MVFR conds. A few SHRA may make it to leeward sides but otherwise, VFR conds should prevail.
AIRMET Sierra for mtn obsc is in effect for windward portions of Oahu and Molokai.

Marine

Fresh to strong easterly trades will continue through the weekend, as the surface ridge remains north of the area. This supports the Small Craft Advisory (SCA) continuing for the windier channels and waters around Maui County and the Big Island each day.
Surf along south facing shores will hold steady today due to a mix of a fading south-southwest swell and a small, medium-period southeast swell moving through. A fresh, long-period south swell is expected to arrive tonight into Friday, then peak late Friday into Saturday. This swell could produce near warning-level surf through its peak late Friday into Saturday. A gradual downward trend is expected Sunday into early next week. After this swell moves out, very little swell is expected next week beginning around Tuesday.
Surf along north-facing shores will remain up above the summertime average (flat) today as a short-period north- northwest swells move through. A downward trend is expected Friday through the weekend.
Surf along east-facing shores will remain small and choppy each day due to a limited trade wind fetch upstream of the islands.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov