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. Northeast winds up to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 76 near the shore to around 66 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 88 near the shore to around 79 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 40 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 75. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Breezy. Partly sunny with scattered showers. Highs around 87. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy with scattered showers. Highs 76 to 83 in the valleys to around 67 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then frequent showers after midnight. Lows 65 to 70 in the valleys to around 62 above 4000 feet. East winds up to 20 mph. Chance of rain 80 percent.

Tuesday: Mostly cloudy. Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 78 to 83 in the valleys to around 70 above 4000 feet. East winds up to 20 mph. Chance of rain 80 percent.

North Kaua’i

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

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 69 to 76. East winds up to 15 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 87. East winds up to 15 mph. Chance of rain 70 percent.

East Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 79 to 87. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 67 to 78. Northeast winds 10 to 15 mph decreasing to up to 10 mph after midnight. Chance of rain 70 percent.

Tuesday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 88. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Moderate to breezy easterly trade winds are expected to persist through the week, with clouds and showers favoring windward and mauka locations overnight through the mornings. Shower coverage is expected to increase tonight through midweek as an area of moisture associated with former Tropical Cyclone Adrian moves through from east to west. Drier trade wind conditions will return through the second half of the week through next weekend.

Discussion

Guidance remains in good agreement and depicts moderate to breezy easterly trades holding through the week as the surface ridge remains anchored to the north. Clouds and showers will favor windward and mauka locations each day, with a potential increase in coverage tonight through midweek as a large area of enhanced low-level moisture moves through from east to west. This increase in moisture combined with a weak mid-level trough and the trade wind inversion lifting to 8-10 kft may allow a few more showers to make it over our dry leeward locations of the smaller islands overnight through the mornings. A return of drier trade wind conditions is anticipated through the second half of the week through next weekend as the area of moisture shifts west of the islands and mid-to-upper heights rise. These higher heights could lead to temperatures climbing slightly above average each day.

Aviation

Moderate to breezy trade winds will likely persist through this afternoon. Low clouds and showers carried by the low-level trade wind flow will continue to move across windward facing slopes and coastal areas this morning. Brief periods of MVFR conditions may occur along some windward areas, with isolated mountain obscuration possible over some higher terrain. Otherwise, expect VFR conditions to prevail across most of the state today.
AIRMET Tango remains in effect for Tempo moderate low-level turbulence over, and downwind of the higher terrain of all islands due to the strong trade winds. This AIRMET will likely continue through this afternoon based on the latest guidance.
By tonight, increasing low-level moisture is expected to begin moving in from the east. The coverage of low clouds and showers may increase, especially over the windward sections of the Big Island and Maui. This may result in widespread MVFR conditions developing later tonight over windward facing slopes of the eastern islands. This enhanced moisture may then spread to the central and western end of the island chain on Tuesday.

Marine

A ridge of high pressure north of the islands will keep moderate to locally strong trade winds in place through the weekend. A Small Craft Advisory is now in effect for the typically windy waters around Maui and the Big Island through Tuesday, and this will likely need to be extended through much of the week.
Surf along south facing shores will remain near or above the summertime average through Thursday, with a peak expected Tuesday and Wednesday. South shore surf will then decline to mainly background levels Friday through next weekend.
Surf along north facing shores will hold at typical summertime levels during the next 7 days. East shore surf will change very little through the weekend, remaining at slightly below normal levels.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov