Photo Credit: Brendan Stephen

West Kaua’i

Today: Breezy. Mostly sunny with isolated showers. Highs around 90 near the shore to around 78 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 73 near the shore to around 62 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny with isolated showers. Highs around 89 near the shore to around 77 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 82 to 90. East winds 10 to 20 mph. Chance of rain 50 percent.

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

Wednesday: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 82 to 90. East winds 15 to 20 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Showers in the morning, then scattered showers in the afternoon. Highs 76 to 87 in the valleys to around 67 above 4000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 80 percent.

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then showers after midnight. Lows 64 to 72 in the valleys to around 60 above 4000 feet. East winds 10 to 20 mph. Chance of rain 80 percent.

Wednesday: Mostly cloudy. Breezy. Showers in the morning, then scattered showers in the afternoon. Highs 75 to 86 in the valleys to around 67 above 4000 feet. East winds 10 to 20 mph. Chance of rain 80 percent.

North Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 78 to 90. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 67 to 74. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 70 percent.

Wednesday: Partly sunny with scattered showers. Highs 77 to 89. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly cloudy with scattered showers. Highs 75 to 87. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 66 to 78. East winds 10 to 15 mph. Chance of rain 70 percent.

Wednesday: Mostly cloudy with scattered showers. Highs 74 to 87. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A weak low level trough axis has drifted just west of Kauai this morning, more stable air will stream in from the east to decrease shower activity as trade winds strengthen through Wednesday. Another uptick in showers will be possible from Thursday into Saturday morning as another weak disturbance moves through the island chain. Drier trends with lighter winds return from Saturday through the first half of next week.

Discussion

Looking at the Hawaii region from the GOES weather satellite perspective, we see the low level trough axis has drifted west of Kauai this morning. More stable air just east of the state will stream into each island today decreasing shower trends statewide through Wednesday.
Another low level trough will move into the eastern islands on Thursday, yet again briefly increasing shower trends into Saturday. A weak upper level low drifting just east of the state may also assist in producing unstable clouds in the trade wind flow just upstream of the island chain. Drier trends return from late Saturday morning onward.
Moderate to locally breezy trade winds will continue through Thursday under a broad subtropical ridge. Expect a slight decrease in trade wind speeds with a hybrid expansion in daytime sea breeze winds along western terrain sheltered slopes from Friday through the first half of next week.

Aviation

Drier and more stable conditions are expected today in the wake of a low level trough that moved across the islands yesterday evening. Latest satellite imagery this morning shows some clouds and showers with occasional MVFR conditions lingering over windward Big Island, where AIRMET Sierra remains in effect for tempo mountain obscuration. Otherwise, VFR flight conditions are expected for most locations throughout the next 24 hours.
AIRMET Tango for moderate low-level turbulence downwind of island terrain will likely be needed later this morning as easterly trade winds become locally strong today.

Marine

A ridge of high pressure north of the state will keep fresh to strong trades in place through Wednesday. The trades will ease slightly Thursday through Saturday as an approaching front weakens the ridge north of the islands. A Small Craft Advisory (SCA) is now in effect for all coastal waters through 6 PM this evening due to winds and/or elevated seas. The SCA continues through 6 PM Wednesday due to strong winds for most waters from Oahu eastward. The SCA will likely need to be extended through at least Wednesday night for the windier waters around Maui and the Big Island.
The current moderate to large, medium period north swell will slowly decline through the remainder of the work week. A High Surf Advisory remains in effect through 6 PM this evening for most north facing shores across the state. Surf along west facing shores will remain slightly elevated with the influence of the north swell during the next couple days. East shore surf will increase a bit today and Wednesday in response to strengthening trades over and upstream of the islands. The surf will then trend lower Thursday through the weekend as the trades ease a bit. However, east facing shores exposed to the north swell will continue to see some wrap during the next couple days. South shore surf will remain small with mainly background south and southeast swells during the next 7 days.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for north facing shores of Niihau, Kauai, Oahu, Molokai, Maui and the Big Island.
Small Craft Advisory until 6 PM HST this evening for Kauai Northwest Waters, Kauai Windward Waters, Kauai Leeward Waters, Kauai Channel, Oahu Windward Waters.
Small Craft Advisory until 6 PM HST Wednesday for most Hawaiian Coastal Waters.

Data Courtesy of NOAA.gov