Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 89 near the shore to around 77 above 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 67 to 72 near the shore to around 58 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 89 near the shore to around 77 above 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

South Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs around 86. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 65 to 71. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Breezy. Partly sunny with scattered showers. Highs around 86. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 76 to 83 in the valleys to around 67 above 4000 feet. East winds up to 15 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 58 to 63 in the valleys to around 53 above 4000 feet. East winds up to 15 mph. Chance of rain 60 percent.

Wednesday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 76 to 83 in the valleys to around 67 above 4000 feet. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 60 percent.

North Kaua’i

Today: Partly sunny with scattered showers. Highs 79 to 88. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 61 to 71. Southeast winds up to 10 mph. Chance of rain 60 percent.

Wednesday: Partly sunny with scattered showers. Highs 79 to 88. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 87. Northeast winds 10 to 15 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 59 to 73. Northeast winds up to 15 mph. Chance of rain 60 percent.

Wednesday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 87. Northeast winds 10 to 15 mph. Chance of rain 60 percent.

Detailed Forecast

Synopsis

Breezy easterly trade winds will continue into midweek, with clouds and showers favoring windward and mauka locations as pockets of moisture move through. Trades will ease through the second half of the week and upcoming weekend, which will allow for localized land and sea breeze conditions to develop for some leeward areas. These lighter winds combined with increasing moisture moving in from the east could result in better chances for a few afternoon showers over our parched interior and leeward areas of the smaller islands, where drought conditions continue to expand in coverage.

Discussion

Guidance remains in decent agreement and depicts the breezy easterly trades holding through Wednesday as the surface ridge remains positioned to the north. A small area of moisture shown on satellite (around 1.3″ PWs) moving through will support scattered windward shower coverage through the morning hours, with some making it into leeward areas periodically. Upper air soundings at Lihue and Hilo reflected this earlier with PWs ranging from a dry 1.2-1.3″ and a subsidence inversion positioned around 8 kft. Strong upper ridge over the region will maintain stable conditions, which will limit accumulations.
A transition is anticipated through the second half of the week as a weakness forms in the ridge due to an upper trough and its attendant cold front digging southward over the northern Pacific. Low-level flow will trend down beginning Thursday, with winds potentially lowering enough by this weekend for localized land and sea breezes to form over our leeward areas. A combination of upper heights slightly lowering as the upper trough nears the area from the north and increasing moisture moving in from the east will support better cloud/shower coverage this weekend into early next week. This setup along with the potential for localized sea breezes could lead to much needed afternoon showers over our leeward areas where drought conditions prevail.

Aviation

Moderate to locally breezy conditions will persist today as surface high pressure resides to the north of the area. Scattered showers will mainly affect windward locations with isolated activity elsewhere. Expect brief periods of MVFR ceilings and visibility associated with this activity, but nothing widespread.
AIRMET TANGO for tempo moderate low-level turbulence remains in effect.

Marine

Moderate to locally strong trade winds will continue into Wednesday in response to the pressure gradient created by a broad surface ridge of high pressure centered north of the state. The Small Craft Advisory (SCA) has been extended in time by a day and will now be effect for the typically windier waters around Maui County and Big Island through Wednesday afternoon. As ridging to the north weakens Wednesday and Thursday, trade winds will slightly ease back to more gentle to moderate speeds. A surface trough north of the area traveling to the east will keep the downstream pressure gradient from the high north of the region weak enough to maintain generally gentle to moderate winds.
Relatively small, medium period east swell originating from former Tropical Cyclone Jova has been building into the local waters. This swell will hold above seasonal average east-facing shore surf through the day. This swell will begin its gradual decline early Wednesday. Eastern exposures will experience more typical small, short period trade wind swell that produce below seasonal surf through the remainder of the week. As this ongoing small 2 foot, medium 14 second south (180-190 degree) swell passes around the island chain, south-facing shore waist to near chest high surf will remain just below late summer normals through today. This swell will fade Wednesday, with another small bump in south shore surf due this weekend. Small surf along those west shores better exposed to south wrap. Flat conditions along north-facing shores with no significant northern swell anticipated the next several days.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov