Photo Credit: Jason Weingardt

West Kaua’i

Rest Of Today: Sunny. Highs around 83 near the shore to around 72 above 3000 feet. Light winds.

Tonight: Mostly clear. Lows 64 to 70 near the shore to around 57 above 3000 feet. Light winds.

Monday: Mostly sunny. A 20 percent chance of showers in the afternoon. Highs 81 to 86 near the shore to around 72 above 3000 feet. Light winds.

South Kaua’i

Rest Of Today: Sunny. Highs around 82. Light winds.

Tonight: Mostly clear. Lows 63 to 68. Northeast winds around 10 mph.

Monday: Mostly sunny. A 20 percent chance of showers in the afternoon. Highs 80 to 86. Northeast winds around 10 mph in the morning becoming light.

Kaua’i Mountains

Rest Of Today: Mostly sunny in the morning, then partly sunny with a 20 percent chance of showers in the afternoon. Highs 73 to 79 in the valleys to around 64 above 4000 feet. Light winds.

Tonight: Partly cloudy. Lows 58 to 63 in the valleys to around 54 above 4000 feet. Light winds.

Monday: Mostly sunny with slight chance of showers in the morning, then mostly cloudy with chance of showers in the afternoon. Highs 72 to 79 in the valleys to around 64 above 4000 feet. Light winds. Chance of rain 40 percent.

North Kaua’i

Rest Of Today: Sunny. Highs 74 to 83. Light winds.

Tonight: Mostly clear. Lows 60 to 68. Light winds.

Monday: Mostly sunny with a 20 percent chance of showers. Highs 74 to 83. Light winds becoming northwest up to 10 mph in the afternoon.

East Kaua’i

Rest Of Today: Mostly sunny. Highs 73 to 83. Light winds.

Tonight: Partly cloudy. Lows 59 to 70. North winds up to 10 mph.

Monday: Mostly sunny in the morning then becoming partly sunny. A 20 percent chance of showers. Highs 73 to 83. Light winds becoming east up to 10 mph in the afternoon.

Detailed Forecast

Synopsis

Moderate trade winds will will hold around the Big Island for the next couple of days, while a nearby surface ridge produces lighter and at times variable winds across the rest of the state. Very stable and rather dry conditions will continue. Stronger trade winds are due during the middle of next week, possibly pushing a dissipating front over the islands that could increase mainly windward rainfall.

Discussion

Dry, stable, and somewhat stagnant conditions prevail over most the state to start the new year. A surface ridge stalled about 125 miles north of Kauai is maintaining gentle to moderate trade winds around the Big Island and east Maui, and weaker east to southeast winds across the rest of the state have been overpowered by light land breezes. A robust ridge aloft overhead is producing very stable conditions with an inversion based between 4,500 and 5,500 ft, and low level moisture is limited. As a result, most areas have been dry overnight, while a few light showers have been observed over windward Big Island.
Little change is due for the rest of the holiday weekend. Best chances for isolated light showers will be across windward areas, though daytime sea breezes will generate clouds and a slight chance of showers across leeward terrain each afternoon.
The background winds will shift out of the north on Tuesday as a surface high racing across the Pacific along 32N nears our longitude. Ridging aloft will hold, keeping stable conditions in place and maintaining rather dry weather as a front approaches.
Tuesday night into Thursday, the surface high will pass north of the islands, bringing a brief shot of moderate to breezy trade winds and pushing the shallow and weak front over the islands. The ridge aloft will maintain stability and help focus rainfall over windward slopes, with minimal showers expected for leeward areas. The GFS and ECMWF still differ on the details, but expect the shallow front to reach Kauai late Tuesday, drift to the central portion of the island chain Wednesday, and dissipate near the eastern end of the state Thursday.
Stable and somewhat dry trade wind weather is favored by Friday, followed by a potential disruption of the trade winds next Sunday.

Aviation

A weak surface ridge north of the state will maintain light to locally moderate east to southeast winds across the islands. This will allow local afternoon sea breeze and nighttime land breeze circulations to develop across sheltered leeward sections of most of the islands through early Monday. Stable and dry atmospheric conditions across the region will continue to limit the coverage of showers during the next couple of days. Some low clouds and light showers moving into windward sections may cause brief periods of MVFR ceilings. In addition, cloudiness may increase over some leeward areas after the sea breezes form later today. Otherwise, expect VFR conditions to prevail through early Monday morning.

Marine

A ridge of high pressure just north of the state will produce light east or variable breezes around Kauai, with gentle to moderate east to southeast winds across the remainder of the state, through the day. The slight northward movement of this ridge Monday will allow for more areawide moderate east trades. The tail end of a cold front will pass through late Tuesday with high pressure filling in behind the boundary Wednesday. Veering mid week winds will strengthen, moderate to locally fresh north northeast winds, as a result of the tighter pressure gradient south of the high. There will be a higher probability for more shower activity Tuesday and Wednesday in association with the weak frontal passage.
The ongoing moderate size, medium period west northwest swell that peaked Friday will be slowly declining through the day. A fetch of gale force winds far northwest of the islands has generated a large, long period west northwest (310-320 degree) swell. This swell will begin to fill in around the islands later today and peak surf at XL warning levels along many north and west-facing shores Monday. This swell will slowly decline through the middle of the week. Weak trade flow and small background south swell will equate to small surf along east and south-facing shores through the week.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov