Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny with isolated showers. Highs around 78 near the shore to around 66 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 66 near the shore to around 55 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Mostly sunny with isolated showers. Highs around 79 near the shore to around 67 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 77. East winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 62 to 67. East winds 15 to 20 mph. Chance of rain 50 percent.

Saturday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 78. Northeast winds 15 to 20 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 65 to 73 in the valleys to around 60 above 4000 feet. East winds 10 to 20 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy. Breezy. Numerous showers in the evening, then frequent showers after midnight. Lows 55 to 60 in the valleys to around 49 above 4000 feet. East winds 10 to 20 mph. Chance of rain 80 percent.

Saturday: Mostly cloudy. Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 66 to 74 in the valleys to around 61 above 4000 feet. East winds 15 to 20 mph. Chance of rain 80 percent.

North Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 70 to 77. 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 58 to 67. East winds 10 to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 71 to 78. East winds around 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly cloudy with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 70 to 77. East winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 56 to 68. East winds 10 to 15 mph. Chance of rain 70 percent.

Saturday: Mostly cloudy with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs 71 to 78. East winds around 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Breezy trade winds will prevail through the forecast period, potentially strengthening early next week. Clouds and showers will favor windward and mauka areas, with shower enhancement likely as destabilizing upper troughs pass by.

Discussion

Satellite loop shows a broad anticyclonic circulation associated with a high far north of the main Hawaiian Islands. Along the southern flank of this high, breezy easterly trade winds persist across local waters this morning. Models show this flow will continue through the weekend as the high moves slowly southeastward and gradually weakens. The high will dissipate far northeast of the islands on Monday, but a new high building northwest of the islands will drive breezy to strong trade winds through next week.
Upper troughing will prevail into next week, except for a brief period tonight and Saturday, when weak upper ridging will develop over the islands. Weak upper troughing exists across the islands this morning, with deep convection south of the islands and high clouds across the Big Island marking its eastern flank. The overall weather pattern will be fairly wet, especially for windward areas. Expect afternoon showers over leeward Big Island slopes as well. Another upper trough, expected to develop Sunday into Tuesday, may form a closed low over the islands, leading to a period of increased instability and very wet trade wind weather. Models show this upper trough may linger all week once formed. A few thunderstorms may develop during this time, depending on how the trough evolves, but confidence remains too low to include these in the gridded database.

Aviation

VFR conditions will prevail with breezy trade winds bringing occasional MVFR clouds and showers to windward and mauka areas. Will see an uptick in showers across the state this morning as a plume of moisture moves through which could result in a period of tempo mountain obscurations and the issuance of AIRMET Sierra.
Otherwise, no AIRMETs are in effect.

Marine

Surface high pressure centered far north of the main Hawaiian Islands will move southeast closer to the state and stall over the next several days. The high will dissipate far northeast of the islands on Monday, but a new high building northwest and north of the islands will continue to support breezy to locally strong trade winds through next week. The strongest winds will be confined to the typically windier waters around Maui County, the Big Island, and the Kaiwi Channel today. Therefore, the Small Craft Advisory (SCA) continues for these areas through today, then gets pulled back to the typically windier waters around Maui County and the Big Island tonight through Saturday. It is possible that the remaining coastal zones will be added back into the SCA early next week with strong to locally near-gale force trade winds expected Monday and Tuesday.
Choppy wind waves are expected well into next week, keeping surf along east facing shores rough throughout the forecast period. Surf along north facing shores will remain small through the morning, then trend upwards slowly this afternoon as a moderate north- northeast swell begins to fill in across the islands. This north- northeast swell will peak over the weekend and gradually trend down early next week. Additionally, a long period northwest swell will arrive on Saturday. Surf will likely build and peak near High Surf Advisory thresholds across exposed north and west facing shores late Sunday into early Monday before the west- northwest swell declines Monday night. A small to moderate, long-period south swell has filled in across south facing shores this morning and will peak later today into Saturday, before easing Saturday night.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov