Photo Credit: Brendan Stephen

West Kaua’i

Today: Sunny. Highs 78 to 87 near the shore to around 73 above 3000 feet. East winds 10 to 15 mph.

Tonight: Mostly clear. Lows 65 to 71 near the shore to around 58 above 3000 feet. Northeast winds around 10 mph.

Tuesday: Sunny. Highs 79 to 87 near the shore to around 73 above 3000 feet. East winds 10 to 15 mph.

South Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 77 to 85. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers. Lows around 69. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny with isolated showers. Highs 78 to 86. Northeast winds around 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Breezy. Partly sunny with scattered showers. Highs 71 to 79 in the valleys to around 63 above 4000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 60 to 68 in the valleys to around 57 above 4000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny with isolated showers. Highs 72 to 79 in the valleys to around 64 above 4000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

North Kaua’i

Today: Mostly sunny with scattered showers. Highs 73 to 83. East winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with scattered showers. Lows 62 to 70. East winds 10 to 15 mph. Chance of rain 40 percent.

Tuesday: Mostly sunny with isolated showers. Highs 73 to 83. East winds 10 to 15 mph. Chance of rain 20 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 70 to 83. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 73. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Tuesday: Mostly sunny with isolated showers. Highs 71 to 83. East winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Typical trade wind weather is expected for most of this week, with moderate to breezy wind speeds and scattered showers focused over windward and mountain areas primarily during the overnight and morning hours. The exception is Tuesday into Wednesday, when a plume of moisture is forecast to move in from the east, increasing windward shower activity. Trades will weaken Friday into next weekend.

Discussion

Surface high pressure remains centered far northeast of the state, driving moderate to locally breezy easterly trade winds, with a mid to upper-level trough just east of the Big Island. The latest satellite and radar imagery shows the band of enhanced low clouds and showers near Kauai and Oahu yesterday evening has weakened and shifted just north of Kauai early this morning. There is also a small area of showers moving into windward Big Island, but mostly isolated clouds and showers elsewhere around the state. Overnight rainfall totals have been mostly in the quarter to half inch range for Kauai, with totals remaining minimal elsewhere, owing to a fairly shallow low-level moisture pool.
Through the day today, we should return to our typical fair trade wind weather with moderate to breezy trade winds and isolated to scattered showers over windward and mauka areas. On Tuesday, a plume of moisture will move in from the east, which should give a boost to shower activity over windward and mauka areas of Maui County and the Big Island during the day. The rest of the islands should see an increase in windward showers Tuesday night into Wednesday morning as the plume continues westward and lingers around Kauai. A dry air mass will follow on Wednesday.
Thursday night into Friday, trades will begin to weaken and veer out of the southeast as a front approaches the state from the northwest. Friday should be a transition day, with light southeast flow over the western half of the state and moderate to locally breezy east to east-southeast winds over the eastern half. Expect a light and variable wind pattern with mostly fair weather for next weekend.
A hot spot over Halemaumau Crater on the Big Island continues to be seen on infrared satellite imagery. The University of Hawaii Vog Model shows that SO2 emissions should remain confined to portions of the Big Island and adjacent waters to the west and southwest through most of this week. However, vog will likely increase across the rest of the state Friday through the weekend as the trades weaken and veer out of the southeast.

Aviation

Breezy easterly trade winds will persist throughout the 24 hour period, with clouds and showers favoring windward and mauka locations. Periods of MVFR CIGS/VSBYS are expected in showers, particularly over the western end of the state, where a remnant low-level band of moisture remains. Conditions should gradually improve through the day as this band of moisture diminishes and shifts north of the area. Another area of moisture moving over the eastern end of the state has led to increasing shower coverage for the windward areas of Big Island, which may persist and spread to Maui through the early morning hours today.
An AIRMET SIERRA for temporary mountain obscuration is in effect for windward Kauai and will likely persist through the early morning hours. This may need to be expanded to cover the windward areas of the Big Island later this morning due to the increasing shower coverage.

Marine

Multiple overlapping northwest swells (300-320) are expected through Friday and beyond. Surf heights will likely reach advisory levels on Thursday, Friday, and possibly into the weekend along exposed north and west facing shores. Surf along south and east facing shores is expected to remain small through the week.
Strong high pressure over the northeast Pacific will hold over the next several days then gradually weaken. So will fresh to strong trade winds across most local waters. The Small Craft Advisory (SCA) for the typically windier waters around Maui County and the Big Island has been extended through Tuesday.

Fire weather

No critical fire weather conditions are expected for the next seven days. Trade winds will continue to remain at moderate to locally breezy speeds with relative humidities staying above critical levels through most of this week. Trades should ease by next weekend.

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.

Kauai Now Weather is brought to you by Blue Hawaiian Helicopters.