Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 72 above 3000 feet. Light winds. Chance of rain 20 percent.

Tonight: Mostly clear with isolated showers. Lows around 67 near the shore to around 56 above 3000 feet. Light winds. Chance of rain 20 percent.

Friday: Mostly sunny. Isolated showers in the afternoon. Highs around 84 near the shore to around 72 above 3000 feet. Light winds becoming southwest up to 10 mph in the afternoon. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 81. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with scattered showers. Lows 63 to 68. Northeast winds around 10 mph. Chance of rain 50 percent.

Friday: Mostly sunny with isolated showers. Highs around 81. Northeast winds up to 10 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 71 to 78 in the valleys to around 62 above 4000 feet. Light winds. Chance of rain 40 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 56 to 61 in the valleys to around 49 above 4000 feet. Light winds. Chance of rain 70 percent.

Friday: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 71 to 78 in the valleys to around 62 above 4000 feet. Light winds becoming north up to 15 mph in the afternoon. Chance of rain 40 percent.

North Kaua’i

Today: Mostly sunny in the morning, then partly sunny with scattered showers in the afternoon. Highs 74 to 84. Northeast winds up to 10 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with scattered showers. Lows 59 to 67. East winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Friday: Mostly sunny. Scattered showers in the afternoon. Highs 74 to 84. Northeast winds up to 10 mph. Chance of rain 40 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 74 to 83. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 40 percent.

Tonight: Partly cloudy with scattered showers. Lows 56 to 69. North winds up to 10 mph in the evening becoming light. Chance of rain 50 percent.

Friday: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs 74 to 83. Northeast winds up to 10 mph. Chance of rain 40 percent.

Detailed Forecast

Synopsis

Trade winds will decrease today, thanks to a weakened ridge to our north. A passing weak front may boost showers this weekend. Moderate trades will return Sunday into next week after the front passes by.

Discussion

Troughing far to our north has put a dent in the subtropical ridge, resulting in a forecast of decreasing trade winds today. Trade winds will continue to decrease into Friday as a front sinks southward. Winds will remain a touch stronger near the Big Island, but background flow will be light enough to allow development of local land and sea breezes across portions of the smaller islands, especially across sheltered leeward areas. Mauka cloud cover will increase as sea breezes form. Current satellite loop shows an area of broken to overcast low clouds moving across the islands and adjacent windward waters, while radar shows scattered moderate showers within this cloud cover favoring windward and mauka areas.
Models show the approaching front will weaken as it sinks southward. However, it will introduce additional moisture and fuel increased showers this weekend. High clouds along the southeastern flank of a weak upper low just north of Kauai are spreading eastward across the islands this morning. Expect sporadic high cloud cover as the upper low moves eastward and dissipates over the next few days. High pressure will strengthen to our north next week after the front passes by, allowing trade winds to return to at least moderate strength statewide Sunday and afterward.

Aviation

Light to moderate trade winds will persist through the forecast period. Clouds and showers will favor windward slopes and coasts and be most active in the late night and morning hours. Sea breezes will drive shower development across sheltered leeward areas in the afternoon and early evening hours. Locally heavy showers are possible over higher elevations on the Big Island. Land breezes will replace sea breezes after sunset and promote overnight clearing. Expect brief MVFR CIG or VIS in showers. Otherwise, VFR conditions will prevail statewide. AIRMET Sierra is in effect for north and east facing slopes of the smaller islands for MVFR ceilings within passing showers. No other AIRMETs are in effect or anticipated at this time.

Marine

Easterly trade winds are steadily trending down this morning due to a front passing to the north. Guidance shows this trend continuing through Friday as the tail-end of the front moves into the area. This will translate to localized land and sea breezes, which may continue through early Saturday. Thereafter, northeast (040 deg) winds will return to moderate to fresh levels late Saturday through Monday as the ridge builds eastward and the frontal boundary diminishes in the area. Northeast winds will shift out of the east Tuesday through midweek.
Surf along north facing shores will trend up beginning later today as a fresh medium-period north-northwest swell arrives. This will be a long-lived event due to the evolution of the generation source over the past few days near the Aleutians and the current large gyre that has setup far north of the islands near Kodiak. Guidance shows this event peaking over the weekend, likely delivering a late season advisory, then slowly easing early next week.
Surf along exposed south facing shores will remain up into next week as a medium-period small south-southeast swells moves through. Additionally, small background south and south-southwest long- period swells are possible beginning early next week. A combo of the southerly and southeasterly swells will be enough to keep the surf up each day through middle of next week.
Surf along east facing shores will remain small through early next week due to the lack of easterly trades locally and upstream across the eastern Pacific.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov