Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 84 near the shore to around 70 above 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening, then scattered showers after midnight. Lows around 68 near the shore to around 57 above 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Friday: Breezy. Mostly sunny with isolated showers. Highs around 85 near the shore to around 70 above 3000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 20 percent.

South Kaua’i

Today: Breezy. Mostly cloudy with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 75 to 82. East winds 15 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 67. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Friday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 76 to 83. East winds 15 to 20 mph. Chance of rain 60 percent.

Kaua’i Mountains

Today: Breezy. Showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 70 to 81 in the valleys to 58 to 63 above 4000 feet. East winds 10 to 20 mph decreasing to up to 15 mph in the afternoon. Chance of rain near 100 percent.

Tonight: Breezy. Mostly cloudy with numerous showers. Lows around 65 in the valleys to around 54 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Friday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 70 to 81 in the valleys to around 61 above 4000 feet. East winds 10 to 20 mph. Chance of rain 60 percent.

North Kaua’i

Today: Mostly cloudy with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 74 to 85. 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 61 to 71. East winds 10 to 15 mph. Chance of rain 60 percent.

Friday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 74 to 85. East winds up to 20 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 69 to 80. East winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 63 to 71. East winds 10 to 15 mph. Chance of rain 60 percent.

Friday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 70 to 81. East winds 10 to 20 mph. Chance of rain 60 percent.

Detailed Forecast

Synopsis

Breezy to locally windy trade winds will continue into Friday morning. Expect enhanced trade wind showers through this morning as a band of unsettled clouds rides through the islands on the trade winds. These showers will decrease in coverage later this afternoon as the band drifts west of the island chain. Trade wind speeds will decrease slightly from Friday into the weekend as the high pressure ridge to the north weakens and a low pressure system deepens far northwest of the state.

Discussion

Satellite imagery this morning shows a lingering band of unsettled showers drifting through the islands on the trade winds. Expect enhanced showers to last through this morning with rainfall amounts favoring windward and mountain slopes. These extra showers should ease up by mid morning as more stable clouds will fill into the Hawaii region from the east.
Wind speeds will continue at moderate to locally windy levels into Friday morning. The high pressure system northeast of the state will drift farther towards the east. A cut off surface low will also deepen far northwest of Kauai. The forward motion on the cut off low northwest of the islands stalls as it pushes up against the ridge. The movement of these two surface pressure systems will weaken the ridge north of the island chain and decrease wind speeds from Friday afternoon into Saturday with more moderate trade winds lasting into the first half of next week.
Next week's weather starts with moderate east to southeast wind flow and fairly dry conditions on Monday and Tuesday. Breezy easterly winds with brief passing showers may return from Tuesday night onward.

Aviation

Breezy to locally windy trade winds will prevail into Friday morning. Clouds and SHRA with MVFR conds will continue to favor windward and mauka areas, with isol SHRA reaching leeward areas.
AIRMET Sierra in effect for tempo mtn obsc for all islands.
AIRMET Tango is in effect for moderate low-level turb downwind of the terrain for all islands, with little change expected through the forecast period.

Marine

A 1030 mb surface high northeast of the state, will slowly drift eastward over the next several days. This feature will help drive strong to locally near gale east northeasterly trade winds across the islands through Thursday. By Friday, the high is forecast to weaken, as low pressure develops well northwest of Hawaii. In response, easterly winds will gradually weaken to light to moderate and shift slightly out of the east southeast by the weekend into early next week. A Small Craft Advisory remain in effect for all Hawaiian coastal waters through Thursday. Beyond Thursday, this hazard may need to be extended for some of the typical windier waters of Maui County and the Big Island as trades ease.
Surf heights will remain below advisory thresholds for all shores through the forecast period. Offshore buoys are showing signs of the new medium period northwest swell filling in. Can expect surf to rise locally by the early morning hours and through the afternoon Thursday, peaking Thursday night. Another small, medium period northwest pulse will enter the waters Friday night, peak Saturday, and subside Sunday. Expect these swells to produce small surf along north and northwest facing beaches. Persistent trades will continue to produce choppy, rough surf through the rest of the week along east facing beaches. By this weekend, weakening trades will allow this surf to lower and hold into early next week. Small background southerly swell will lead to small surf along south facing beaches through the forecast period.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Friday for all Hawaiian waters,

Data Courtesy of NOAA.gov