Photo Credit: Brendan Stephen

West Kaua’i

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 83 near the shore to around 71 above 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 69 near the shore to around 59 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Thursday: Mostly sunny with isolated showers. Highs around 83 near the shore to around 71 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 80. Northeast winds 15 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Thursday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 80. Northeast winds 15 to 20 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 70 to 77 in the valleys to around 61 above 4000 feet. East winds up to 20 mph. Chance of rain near 100 percent.

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then frequent showers after midnight. Lows 60 to 65 in the valleys to around 54 above 4000 feet. East winds up to 20 mph. Chance of rain 80 percent.

Thursday: Mostly cloudy. Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 70 to 77 in the valleys to around 61 above 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 80 percent.

North Kaua’i

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 73 to 83. East winds up to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 62 to 70. East winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 70 percent.

Thursday: Partly sunny with scattered showers. Highs 73 to 83. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly cloudy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 73 to 82. Northeast winds 10 to 15 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 60 to 72. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Thursday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 73 to 82. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Breezy easterly trade winds will continue through Thursday, then ease Friday through early next week as the ridge weakens north of the area and an upper disturbance moves in. Showers will favor windward and mauka locations, especially overnight through the early mornings as pockets of moisture move through. As the upper disturbances moves southward into the region, there is a possibility of increasing shower coverage, with some potentially becoming locally heavy.

Discussion

Short-term guidance remains in good agreement and depicts the breezy easterly trades holding through Thursday as the ridge remains anchored to the north. An area of low clouds and enhanced moisture moving through has led to better windward shower coverage, which will continue through the early morning hours today. Stable conditions associated with an upper ridge and plenty of mid-level dry air, however, will limit rainfall amounts. Mostly dry conditions will prevail over the leeward areas of the smaller islands.
Trade winds may weaken Friday into the weekend as an upper trough drops south into the area and a weakness forms in the ridge to the north. Added instability accompanying the upper trough will support a few locally heavier showers. This trend may persist over the weekend and into early next week as a reinforcing upper trough digs southward. Forecast confidence, however, remains poor through this period due to large inconsistencies noted from cycle to cycle over the past several days.

Aviation

Moderate to locally breezy trade winds will maintain showers across mainly windward slopes and coasts, with the greatest concentration of showers expected through this morning. Local sea breezes will encourage cloud and shower development again this afternoon over the Kona coast and mountain slopes. Mainly VFR conditions are expected across TAF locations through the period. However MVFR conditions in heavier showers may generate brief periods of tempo mountain obscuration across some windward areas.
The locally breezy trade winds will continue the need for AIRMET Tango due to moderate low-level turbulence downwind of most island terrain.

Marine

A high pressure system will remain north of the Hawaiian Islands producing moderate to locally strong trade winds into Friday. A low pressure trough forming north of the islands will weaken the trade winds into the moderate range from Saturday into the first half of next week. A Small Craft Advisory remains in effect for the windier waters and channels around Maui and Hawaii Counties.
A small long period south to southwest swell (200-220 degree) will keep small surf heights along south facing shores into the weekend. Moderate trade winds will maintain small surf along east facing shores into Friday.
North and west facing shores will see nearly flat conditions into Sunday, with a small long period northwest (310 degree) swell arriving by Sunday night producing a slight bump in surf heights lasting into Monday before fading away on Tuesday.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov