Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Mostly sunny with isolated showers. Highs around 91 near the shore to around 79 above 3000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with scattered showers. Lows around 73 near the shore to around 62 above 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 88 to 93 near the shore to around 79 above 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

South Kaua’i

Today: Partly sunny with scattered showers. Highs 83 to 91. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 73. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 83 to 90. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy. Occasional showers in the morning, then showers likely in the afternoon. Highs 75 to 88 in the valleys to around 68 above 4000 feet. East winds 10 to 15 mph. Chance of rain 90 percent.

Tonight: Breezy. Mostly cloudy with occasional showers. Lows 65 to 71 in the valleys to around 59 above 4000 feet. East winds 10 to 20 mph. Chance of rain 90 percent.

Wednesday: Breezy. Occasional showers. Highs 75 to 88 in the valleys to around 68 above 4000 feet. East winds 10 to 20 mph. Chance of rain near 100 percent.

North Kaua’i

Today: Partly sunny. Occasional showers in the morning, then showers likely in the afternoon. Highs 77 to 91. East winds 10 to 15 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy with numerous showers. Lows 66 to 75. East winds 10 to 15 mph. Chance of rain 70 percent.

Wednesday: Partly sunny with numerous showers. Highs 77 to 91. East winds 10 to 15 mph. Chance of rain 70 percent.

East Kaua’i

Today: Mostly cloudy. Occasional showers in the morning, then showers likely in the afternoon. Highs 75 to 87. East winds 10 to 15 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy with numerous showers. Lows 65 to 77. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Wednesday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 75 to 87. East winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Persistent high pressure far north of the islands will support locally breezy trade winds through the weekend. Passing showers will periodically dampen most windward areas, with some showers occasionally spreading leeward, especially night and morning.

Discussion

Persistent surface high pressure far N of the islands will support locally breezy trade winds for the foreseeable future. A slow-moving trough aloft just N of the islands will bring some modest mid-level cooling as it drifts S the next couple of days, elevating and weakening the subsidence inversion. This will allow orographic lift to produce a few showers, in addition to random shower clusters arriving on the trades. These will occasionally dampen windward areas, with some showers occasionally spreading leeward, most active night and morning. In contrast, daytime heating will lead to afternoon and evening showers over the Kona slopes.
A low-level trough approaching from the E (remnants of former T.S. Emilia) is forecast to dampen out as it reaches the longitude of the islands Thursday and Friday, but there may be a brief period of slightly weaker winds from late Wednesday into Thursday. While PWAT may diminish tonight into Wednesday, the nearby passage of these remnants may lead to increased PWAT/windward showers.
A mid-level ridge will rebuild over the islands by the weekend, likely reducing shower coverage/frequency.

Aviation

Moderate to locally breezy trades will deliver low cigs and SHRA to windward and mauka locations through the forecast period. Brief MVFR conds can be expected within SHRA but VFR should generally prevail.
AIRMET Sierra is in effect for windward locations of all islands for mtn obsc. Conds should improve by mid-morning.

Marine

An area of surface high pressure north of the state will remain nearly stationary over the next several days and produce moderate to locally strong trade winds across the local waters. A Small Craft Advisory has been extended through Thursday morning for the typically windier waters around Maui County and the Big Island and will likely need to be extended through late this week.
A small, medium- period, background south swell will linger this morning and produce small surf along south facing beaches. Another small, long- period, south swell is expected to arrive late today and peak on Wednesday, then decline through early this weekend. Guidance introduces a 3 foot, long- period, southerly swell late Sunday into early next week. This swell will have originated from a slow moving gale low, currently east of New Zealand. Expect a bump up in surf to above August averages.
Seasonally flat to tiny surf is expected through this week for north facing shores. Breezy trade winds will bring choppy surf conditions to east facing shores through the remainder of this week.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov