Photo Credit: Jason Weingardt

West Kaua’i

Today: Sunny. Highs 86 to 92 near the shore to around 78 above 3000 feet. Northeast winds up to 15 mph shifting to the southwest in the afternoon.

Tonight: Mostly clear. Lows around 72 near the shore to around 62 above 3000 feet. Northeast winds up to 10 mph.

Friday: Sunny. Highs 86 to 92 near the shore to around 78 above 3000 feet. Northwest winds up to 10 mph shifting to the northeast in the afternoon.

South Kaua’i

Today: Mostly sunny. Isolated showers in the morning. Highs 84 to 92. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 70 to 75. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs 86 to 92. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 76 to 85 in the valleys to around 68 above 4000 feet. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with scattered showers. Lows 65 to 70 in the valleys to around 59 above 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Friday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 77 to 84 in the valleys to around 69 above 4000 feet. East winds up to 10 mph. Chance of rain 20 percent.

North Kaua’i

Today: Sunny with isolated showers. Highs 78 to 89. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 65 to 74. Light winds becoming southeast up to 10 mph after midnight. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs 79 to 88. Southeast winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

East Kaua’i

Today: Mostly sunny with isolated showers. Highs 77 to 88. Northeast winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows 65 to 77. North winds up to 10 mph. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs 78 to 89. Northeast winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Dry conditions prevail through the forecast period. Moderate trades will continue through Thursday before giving way to a land and sea breeze pattern through the weekend. Rainfall will be limited during this time.

Discussion

Virtually no change from 24 hours ago as moderate trades and high stability prevail over the islands. A weak upper jet positioned over the area has been a source of high clouds during the last couple of days which has taken the edge off of afternoon heat at times. As the jet weakens coverage of high clouds will follow, though patchy high clouds will likely still find their way into area skies at times on Wednesday. Otherwise, dry conditions and light winds prevail for the foreseeable future. Dry, moderate trades persist for another 36 hours or so from press time this evening. Then, from Friday onward, the large scale pattern will be will be dominated by an eastward extension of the Pacific jet. This will force rather flat but very broad deep layer ridging to build into the Central Pacific from the west resulting in a trend toward even greater stability as the weekend progresses. Meanwhile, trade winds at the surface will further weaken as they are suppressed south of the area. This leaves the islands in a rather non-descript area of the regional MSLP field characterized by weak ridging at the surface and light to variable winds. Afternoon sea breezes and overnight land breezes will dominate during this time. However, given the dearth of moisture and steadily increasing deep layer stability, inland shower development in the afternoon is expected to be sparse or nil.

Aviation

A weak high pressure ridge far north of the Hawaiian Islands will produce light to moderate trade winds through the day with localized land/sea breezes. Brief clouds and showers will focus over windward and mountain areas and favor the night time and early morning hours. Overall VFR conditions will prevail through the forecast period.
AIRMET Tango remains in effect for moderate turbulence in a layer between 15kft and 25kft over Kauai and Oahu. Turbulence will likely diminish through the morning hours.

Marine

A surface high pressure system is located far northwest of the state early this morning. A surface ridge extends from this high to a point about 400 nm north of Kauai. In addition, a weak front located about 225 nm north of Kauai is moving south-southeast slowly. Moderate to locally fresh trade winds are expected to persist across the state today. The front is expected to dissipate north of the area tonight. Another front over the north Pacific will push down from the north-northwest, and will cause the surface high and its associated ridge to move south from tonight through Friday. This will result in the trade winds gradually weakening to light to moderate speeds from late tonight through Friday. This surface ridge will likely weaken, and be in the vicinity of the islands this weekend. Therefore, expect light and variable winds in the vicinity of the western islands, while weak trade winds may linger near the eastern end of the island chain from Saturday into early next week.
The current medium-period northwest (310-320 degrees) swell will continue to gradually build through tonight. This is expected to produce small to moderate surf along exposed north and west facing shores from late tonight into Saturday. A moderate, long- period north-northwest (320-330 degrees) swell arriving Saturday is expected to maintain moderate surf along exposed north and west facing shores from this weekend into early next week. The latest model guidance continues to show forerunners from a much larger, long-period northwest swell reaching the islands next Tuesday. This swell may cause surf to reach the High Surf Warning criteria along most north and west facing shores of the smaller islands Tuesday night. Surf may also be near the High Surf Advisory criteria along west facing shores of the Big Island starting late Tuesday night. Stay tuned for future adjustments in the exact timing, heights, and potential impacts of the surf associated with this significant northwest swell.
Modest surf is expected to persist along south facing shores the rest of this week due to a series of medium- to long-period south to south-southwest (190-200 degrees) swells moving through the area. A fetch of gale force winds located southeast of New Zealand is expected to send a new, long-period south-southwest (200-210 degrees) swell toward the area that may arrive in the islands Monday. This may result in above the seasonal average surf along south facing shores early next week. Elsewhere, the weakening trade winds will result in diminishing surf along east facing shores during the next couple of days, with nearly flat conditions possible along most east facing shores by late this weekend.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov