Photo Credit: Brendan Stephen

West Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 86 to 92 near the shore to around 77 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 73 near the shore to around 62 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Tuesday: Sunny. Scattered showers in the morning. Highs 86 to 92 near the shore to around 77 above 3000 feet. East winds up to 10 mph. Chance of rain 40 percent.

South Kaua’i

Today: Partly sunny with scattered showers. Highs 82 to 89. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 74. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tuesday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 82 to 90. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy with numerous showers. Highs 76 to 86 in the valleys to around 67 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Numerous showers in the evening, then occasional showers after midnight. Lows 64 to 71 in the valleys to around 59 above 4000 feet. East winds up to 15 mph. Chance of rain 90 percent.

Tuesday: Partly sunny. Occasional showers in the morning, then scattered showers in the afternoon. Highs 75 to 86 in the valleys to around 67 above 4000 feet. Northeast winds up to 15 mph. Chance of rain 90 percent.

North Kaua’i

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 77 to 89. 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 66 to 73. East winds around 10 mph. Chance of rain 70 percent.

Tuesday: Partly sunny with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 77 to 89. East winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 70 percent.

East Kaua’i

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 74 to 87. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 66 to 77. Northeast winds around 10 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 74 to 87. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

A weak upper level low over the state will produce periods of enhanced showers into the first half of the week. This low drifts slowly towards the northeast today and tomorrow, moving away from the island chain. More stable trade wind weather returns starting on Tuesday with brief periods of passing showers favoring windward and mountain areas lasting through next weekend.

Discussion

In the big picture this morning, we continue to see a weak upper level low parked over the middle of the state on the water vapor satellite imagery. No lightning strikes were observed last night and no thunderstorms are forecast for today. This weak system will just enhance local windward and mountain shower activity into Tuesday morning.
Far north of the Hawaiian Islands, the subtropical ridge will remain on the weak side this week, as cold frontal systems prowling across the Central Pacific basin will tend to moderate the ridge intensity. Trade wind speeds will therefore remain at more moderate levels lasting into next weekend.
Brief passing showers are expected for the next seven days, mainly over the windward and mountain areas favoring the typical overnight to early morning hours. Subtle changes in the day to day rainfall patterns for each island are shown in this mornings forecast guidance. However, no significant deviations to the typical trade wind rainfall pattern is expected.

Aviation

Moderate to locally breezy trades for the new week. SHRA with low cigs are possible mostly over windward and mauka locations. Periods of MVFR conds are possible in any SHRA.
No AIRMETs are currently in effect.

Marine

A surface ridge will rebuild far north of the state today and lead to fresh to locally strong trades across the region. The recent scatterometer pass indicates winds near 25 KT already occurring along portions of the Alenuihaha Channel. Thus, a Small Craft Advisory (SCA) has been issued for the typical windy coastal waters and channels near Maui County and the Big Island through this evening. This advisory may need to be extend in time.
A moderate, long-period north-northwest swell has arrived at the Hanalei and Waimea near shore buoys. This swell is expected to to peak today, then slowly decline through the week. However, surf still is projected to stay a few feet below advisory levels for north facing shores with this swell.
A 3-foot, long period (15/16 second), south swell can also be noted on the nearshore buoys this morning. This swell will maintain above average surf along south facing shores through the day, though still below advisory levels. Expect the aforementioned swell to slowly decline through the middle of this week. East facing shores will get a boost in choppy surf as the trades return today through mid-week.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST this evening for windier waters and channels near Maui and the Big Island.

Data Courtesy of NOAA.gov