Photo Credit: Braden Jarvis

West Kaua’i

Today: Sunny and breezy. Isolated showers in the morning. Highs 87 to 92 near the shore to around 78 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers after midnight. Lows around 73 near the shore to around 63 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Sunday: Sunny. Highs 86 to 92 near the shore to around 78 above 3000 feet. East winds up to 15 mph.

South Kaua’i

Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 84 to 91. Northeast winds 15 to 20 mph. Chance of rain 40 percent.

Tonight: Breezy. Partly cloudy with isolated showers in the evening, then mostly cloudy with scattered showers after midnight. Lows 71 to 76. Northeast winds 10 to 20 mph. Chance of rain 40 percent.

Sunday: Breezy. Mostly sunny with isolated showers. Highs 85 to 91. East winds 10 to 20 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Breezy. Partly sunny with scattered showers. Highs 74 to 85 in the valleys to around 67 above 4000 feet. East winds up to 20 mph becoming 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows around 69 in the valleys to around 60 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 75 to 85 in the valleys to around 68 above 4000 feet. East winds up to 20 mph. Chance of rain 50 percent.

North Kaua’i

Today: Mostly sunny with scattered showers. Highs 77 to 89. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers. Lows 67 to 74. East winds 10 to 15 mph shifting to the southeast after midnight. Chance of rain 50 percent.

Sunday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 89. East winds up to 15 mph. Chance of rain 40 percent.

East Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 75 to 87. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 66 to 77. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 75 to 88. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Fresh trade winds with limited windward showers and rather dry leeward conditions will continue through next week.

Discussion

A 1034 mb high far north of the state is driving fresh trade winds. Infrared satellite imagery and radar show showery low clouds moving in from upstream of the smaller islands. These showers are mostly impacting windward and mountain areas and will likely linger into around midday. Soundings from Lihue and Hilo show a dry, stable air mass has moved over the state with precipitable water values just over an inch.
The overall pattern changes very little through the next week with only minor fluctuations in trade wind speeds and a continued stable atmosphere. Mostly sunny/clear conditions expected leeward, while partly cloudy skies and few passing showers windward and mauka. Any passing showers are most likely to occur during the nighttime and early morning hours. However, daytime heating will lead to sea breeze development along the Kona slopes of the Big Island will cause clouds and a few showers each afternoon.

Aviation

A high pressure ridge far north of the Hawaiian Islands will keep moderate to locally breezy trade winds in the forecast through Sunday. Brief periods of showers are possibly especially during the overnight to early morning hours. VFR conditions will prevail outside of showers.
AIRMET Tango remains in effect for moderate low level turbulence over and downwind of island mountains. Conditions are expected to continue through Sunday.

Marine

Fresh to strong easterly trade winds will continue through the upcoming week as high pressure remains positioned far north of the area.
Surf along east facing shores will remain rough and choppy each day due to the persistent fresh onshore breezes. Wave guidance shows the peak period holding around 6-7 seconds through much of the upcoming week.
Surf along south facing shores will remain at background levels through the weekend, then trend up Sunday night through early next week as a long-period southwest swell from the Tasman Sea arrives and moves through. Observations at the American Samoa PacIOOS buoy reflect this new southwest source this morning with the peak energy centered around the 16-18s band (3 ft). This will result in a building trend through the day Monday given the expected travel time, before peaking sometime between Tuesday and midweek. A return of smaller surf with mainly background southerly sources is expected late next week.
As we head into August, water levels are running higher than predicted (0.3 to 0.5 ft), which will lead to minor coastal flooding concerns through the afternoon periods around the peak daily high tides Sunday afternoon through early next week. This combined with a small long-period southwest swell peaking will lead to minor flooding of beaches that normally remain dry, low- lying roads, docks, boat ramps, marina parking lots, and other coastal infrastructure.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov