Photo Credit: Brendan Stephen

West Kaua’i

Today: Mostly sunny with isolated showers. Highs around 85 near the shore to around 72 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 69 near the shore to around 59 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Friday: Mostly sunny with isolated showers. Highs around 85 near the shore to around 72 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 77 to 85. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 70. East winds around 15 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with showers likely in the morning, then mostly sunny with scattered showers in the afternoon. Highs 77 to 85. East winds 15 to 20 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Breezy. Partly sunny with scattered showers. Highs 72 to 80 in the valleys to around 63 above 4000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows 62 to 68 in the valleys to around 56 above 4000 feet. East winds 15 to 20 mph. Chance of rain 70 percent.

Friday: Partly sunny. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs 72 to 80 in the valleys to around 62 above 4000 feet. East winds 15 to 20 mph. Chance of rain 70 percent.

North Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 74 to 85. East winds 10 to 15 mph. Chance of rain 30 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 72. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with scattered showers. Highs 74 to 86. East winds 10 to 20 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 71 to 82. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 73. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Breezy. Partly sunny with scattered showers. Highs 70 to 81. East winds 15 to 20 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Trade winds will strengthen today, then become breezy Friday through the weekend. Clouds and showers will favor typical windward slopes, with an increase in showers expected this weekend through the first half of next week as a disturbance aloft passes overhead.

Discussion

Stable easterly trade wind flow remains over the islands early this morning with a weak trough northwest of Kauai and a 1030 mb surface high to the far northeast. Satellite imagery continues to show partly to mostly cloudy skies across the region, with radar showing isolated showers across mainly windward slopes. Expect trades to strengthen today as the trough weakens further and high pressure builds over the region, with clouds and showers favoring windward and mauka areas. With no areas of organized moisture upstream of the islands rain totals will remain limited today.
Breezy to locally windy trades look to develop over the state on Friday, then continue through the weekend as high pressure settles to the northeast. This will drive an uptick in clouds and showers over windward and mauka areas, with a few showers drifting into leeward areas due to the stronger winds. Expect the strongest winds over the windier areas of Maui County and the Big Island.
Guidance continues to show an upper level low stalling to the west of Kauai over the weekend, then slowly moving across the state early next week. As the low moves across the state expect a boost in to our trade wind showers, with a few brief downpours possible through the first half of next week. Details are still uncertain, but windward and mauka areas could become quite showery through early next week, especially across the western end of the state where the best instability exists. Guidance also continue to hint at an outside chance for some isolated thunderstorms during this time period.
Expect a return to a more typical moderate to breezy trade wind pattern by Wednesday as the upper low moves away from the state.

Aviation

Moderate E winds will gradually strengthen today. SHRA and isol MVFR conds expected windward and mauka locations. VFR conditions will prevail leeward, except for isolated areas of MVFR conds over leeward Big Island in the afternoon and evening.
No AIRMETs are posted, but increased low-level turb to the lee of the terrain is expected by late this morning, likely prompting the issuance of AIRMET Tango.
AMD NOT SKED in for Midway due to missing wind speed and direction.

Marine

Moderate to locally strong easterly trades will gradually return today as a high pressure far northeast of the state shifts south and a weak trough northwest of the state moves farther west. Trades will strengthen to fresh to locally strong Friday and persist into early next week as another high builds north of the state and remains nearly stationary. The Small Craft Advisory (SCA) for typical windy waters around Maui and the Big Island has been extended through Monday. Maalaea Bay has also been added to the SCA as well as the wind direction becomes for favorable for this area and winds strengthen. Additional waters will likely be added Friday as trade winds continue to strengthen and expand in coverage.
Tiny surf will persist along north and west facing shores through Friday. A small, long period northwest swell is expected to fill in Friday night and peak Saturday, bringing small surf along north and west facing shores. Another small, long period northwest swell will fill in late Sunday, maintaining small surf along north and west facing shores into early next week. Small background south swells will continue into Saturday, providing tiny surf for south facing shores. A small, long period south swell may arrive Sunday providing a boost in surf along south facing shores into early next week. Surf along east facing shores will gradually become rough and choppy today through the weekend as trades return.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov