Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly cloudy with scattered showers. Highs around 82 near the shore to around 69 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Cloudy with scattered showers. Lows around 68 near the shore to around 58 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Thursday: Mostly cloudy with scattered showers. Highs around 82 near the shore to around 68 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

South Kaua’i

Today: Breezy. Mostly cloudy with numerous showers. Highs 76 to 82. Northeast winds 15 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Cloudy with occasional showers. Lows around 68. East winds 15 to 20 mph. Chance of rain 90 percent.

Thursday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 76 to 82. Northeast winds 15 to 20 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Breezy. Frequent showers. Highs 68 to 75 in the valleys to around 60 above 4000 feet. East winds 10 to 25 mph. Chance of rain near 100 percent.

Tonight: Breezy. Cloudy with occasional showers. Lows 61 to 66 in the valleys to around 55 above 4000 feet. East winds 10 to 25 mph. Chance of rain 90 percent.

Thursday: Breezy. Cloudy with numerous showers. Highs 69 to 76 in the valleys to around 60 above 4000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

North Kaua’i

Today: Breezy. Frequent showers. Highs 70 to 82. East winds 10 to 20 mph. Chance of rain near 100 percent.

Tonight: Breezy. Cloudy with occasional showers. Lows 61 to 69. East winds 10 to 20 mph. Chance of rain 90 percent.

Thursday: Cloudy and breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 71 to 81. East winds 10 to 20 mph. Chance of rain 70 percent.

East Kaua’i

Today: Frequent showers. Highs 67 to 79. Northeast winds 10 to 15 mph. Chance of rain near 100 percent.

Tonight: Cloudy with occasional showers. Lows 61 to 72. East winds 10 to 15 mph. Chance of rain 90 percent.

Thursday: Cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 67 to 79. East winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

A wet trade wind pattern will persist for the next few days, with rainfall favoring windward and mauka areas. Showers may spread to leeward areas as well from time to time. Expect clearer skies and drier weather by the holiday weekend as upper ridging builds over the islands.

Discussion

A high far north of the state continues to drive breezy trade winds across local waters this morning. Embedded bands of showers favor windward and mauka areas of the islands. High clouds marking the subtropical jetstream continue to block views of the sky as an associated upper trough deepens several hundred miles west of Kauai. Expect the wet pattern to persist today as a band of moisture focused on Kauai and Oahu sags southward.
Cloudy, wet, and breezy trade wind weather will prevail into Friday. Models show the high to our north will merge with another high moving in from the northwest Pacific on Thursday, keeping trade winds at breezy levels across local waters. Winds will weaken slightly Friday as the high moves eastward. Upper troughing will drift closer to the islands through Thursday, leading to decreased stability and denser high cloud cover. The low cloud band focused on Kauai and Oahu will sag southward across all islands today, spreading shower coverage. Decreased stability may cause showers to become heavier. However, breezy trades will keep showers from focusing on any given area, reducing the potential for flooding. There may be periods of snow on the highest elevations of Mauna Kea and Mauna Loa. Models show that moisture should decrease on Thursday.
Expect drier trade wind weather heading into the holiday weekend. Upper ridging will build in from the west, bringing a return to more stable conditions. Trade winds will gradually decline as high pressure to our north is pushed closer to the state.

Aviation

An area of surface high pressure, centered well north of the state, will continue to generate breezy trades through the forecast period. Low level moisture caught up in the flow will bring scattered to numerous showers along the windward slopes and allow for periods of MVFR ceilings and visibility. Isolated showers may push over the higher terrain and affect leeward locations.
AIRMET SIERRA remains in effect above 2000 feet for north through east sections of all islands for tempo mountain obscuration due to clouds and showers.
AIRMET TANGO remains in effect below 8000 feet over and immediately south through west of mountains due to tempo moderate turbulence. AIRMET TANGO also remains in effect between FL240 and FL350 for tempo moderate turbulence.

Marine

Surface high pressure far north the islands continues to drive fresh to locally strong trade winds across the majority of the Hawaiian coastal waters. High winds, a stubborn northeast swell and an incoming northwest swell are all reasons to justify the continuance of the all-coastal water Small Craft Advisory and east-facing coast High Surf Advisory (HSA) for yet another day, or at least through this afternoon. As the high drifts farther east, trade magnitudes will generally remain fresh across more exposed waters…locally strong within the typically windier channels and bays through Thursday before falling off to more moderate to fresh speeds Friday.
Moderate size, short period northeast swell has remained fairly steady with little to no decline. Thus, with little reprieve from stronger trade flow, the swell remains elevated enough to warrant extending the High Surf Advisory (HSA) for east-facing shores through the day. East shore surf is expected to eventually fall below advisory heights this evening or early Thursday. A small, medium period northwest swell will boost north northwest-facing surf a bit today but remain well below advisory levels through Thursday. A larger northwest swell is scheduled to arrive late Thursday and this swell will likely lift north and west-facing shore surf to HSA levels as it peaks out early Friday. While confidence remains low, the next northwest swell that will come in just after Christmas may be high enough to produce XL warning level surf along north shores. A small, medium to long period south to southwest swell passing through late this week will keep south shore surf from going completely flat.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Olomana, Kauai East, Koolau Windward, Molokai Windward, Molokai Southeast, Windward Haleakala, Kipahulu, Big Island East, Big Island North.
Small Craft Advisory until 6 PM HST this evening for all Hawaiian waters,

Data Courtesy of NOAA.gov