West Kaua’i

Tonight: Partly cloudy with isolated showers. Lows around 72 near the shore to around 63 above 3000 feet. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 20 percent.

Saturday: Breezy. Mostly sunny with isolated showers. Highs 84 to 91 near the shore to around 76 above 3000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Saturday Night: Mostly clear with isolated showers. Lows around 72 near the shore to around 63 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 71 to 76. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Saturday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 78 to 88. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Saturday Night: Mostly cloudy with scattered showers. Lows around 73. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Breezy. Mostly cloudy with numerous showers. Lows around 68 in the valleys to around 61 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 72 to 80 in the valleys to around 66 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

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

North Kaua’i

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 64 to 74. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 70 percent.

Saturday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 70 to 86. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Saturday Night: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 64 to 74. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 67 to 75. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 76 to 84. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Saturday Night: Mostly cloudy with scattered showers. Lows 67 to 75. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Breezy trade winds will usher in windward clouds and showers through Monday. Hurricane Fausto is expected to weaken to a tropical storm as it approaches the islands and will potentially bring heavy rain, winds and surf to portions of the state Tuesday through Wednesday. Trades will fill in Thursday night in the wake of Fausto.

Discussion

Breezy trade winds will usher in windward clouds and showers through Monday. Incoming clouds and showers will focus over windward and mauka areas, mostly occurring during the nighttime and early morning hours. 00Z soundings show a stable environment across the islands with an inversion around 7000 feet.
The highlight next week will be the approach of now Hurricane Fausto. Fausto is expected to weaken over the next several days as it tracks west across higher shear and cooler waters, reaching the vicinity of the Hawaiian Islands on Tuesday. Main impacts Tuesday and Wednesday include winds, rain and east shores surf, and will be dependent upon Fausto's eventual path. Mitigating effects will be Fausto's quick 15 mph west movement limiting how long it will rain across the same areas. Winds could also be mitigated on a more northerly swing of the track, but more impactful if it slides southward. Still lots of possibilities, so best to look at preparations this weekend and stay tuned for updates to the forecast and any issuance of watches and warnings. Trades will fill in Thursday night in the wake of Fausto and continue into next weekend.

Aviation

Breezy trades continue through the forecast period. Periodic MVFR likely windward and mauka within pockets of deeper moisture and greater shower activity embedded in the trades. Otherwise VFR anticipated.
AIRMET Tango remains in effect for lee turb.

Marine

Robust high pressure far north of the state continues to produce fresh to strong trade winds, but winds drop down a notch tonight. The Small Craft Advisory (SCA) has been trimmed back to just the typically windy waters around Big Island and Maui County due to slight easing of the trades as the high drifts westward. Trades may decline slightly Sunday into Monday, but wind trends become less clear Tuesday due to uncertainty in the eventual track and strength of Hurricane Fausto. Generally speaking, expect winds to veer northeast and strengthen ahead of the cyclone, while winds will actually diminish somewhat south of the storm at a distance from the center. This appears more favored for an area south of the islands. The current National Hurricane Center forecast calls for Fausto to be a tropical storm by Monday with continued weakening as it passes near the islands Tuesday and Wednesday.
The current south-southwest swell continues to produce advisory level surf this afternoon. With a slow decline expected through at least the first part of the night, the High Surf Advisory has been extended through Saturday. Surf along south facing shores may briefly dip below advisory thresholds late tonight or early Saturday, but this will be followed by another pulse of swell that will likely push surf above the advisory level for Saturday and Sunday. The south-southwest swell will then slowly decline early next week, with a smaller south- southwest swell possible during the middle of the week.
Rough east shore surf will remain a notch above seasonal average into Saturday as a result of fresh to strong trade winds. Long-period swell from Hurricane Fausto arrives tonight into Saturday and builds through early next week. The Fausto swell will likely produce advisory- level surf along east facing shores by Sunday or Monday, with the largest surf expected Tuesday or Wednesday depending on the eventual track of the tropical cyclone.
Surf along north-facing shores will remain at flat to tiny levels through the weekend. Some increase is expected as Fausto or its remnants pass over the area Tuesday and Wednesday.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Saturday for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.
Small Craft Advisory until 6 AM HST Sunday 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.

Check out their Kaua‘i Helicopter Tours today!

Data Courtesy of NOAA.gov