West Kaua’i

Tonight: Partly cloudy with isolated showers. Lows 67 to 72 near the shore to around 58 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Monday: Breezy. Mostly sunny with isolated showers. Highs around 83 near the shore to around 73 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Monday Night: Breezy. Partly cloudy with isolated showers. Lows 66 to 71 near the shore to around 57 above 3000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

South Kaua’i

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows 65 to 71. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Monday: Partly sunny. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs around 81. Northeast winds 15 to 25 mph. Chance of rain 70 percent.

Monday Night: Breezy. Mostly cloudy with scattered showers. Lows 64 to 70. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Kaua’i Mountains

Tonight: Breezy. Mostly cloudy with frequent showers. Lows around 61 in the valleys to around 53 above 4000 feet. East winds up to 20 mph shifting to the northeast 10 to 20 mph after midnight. Chance of rain 90 percent.

Monday: Breezy. Mostly cloudy with frequent showers. Highs around 76 in the valleys to around 65 above 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 90 percent.

Monday Night: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows around 60 in the valleys to around 52 above 4000 feet. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

North Kaua’i

Tonight: Mostly cloudy. Showers likely in the evening, then frequent showers after midnight. Lows 61 to 70. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 90 percent.

Monday: Partly sunny. Breezy. Frequent showers in the morning, then showers likely in the afternoon. Highs 76 to 82. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 90 percent.

Monday Night: Breezy. Mostly cloudy with scattered showers. Lows 60 to 69. East winds 10 to 20 mph. Chance of rain 50 percent.

East Kaua’i

Tonight: Mostly cloudy with frequent showers. Lows 59 to 72. Northeast winds 10 to 15 mph. Chance of rain 90 percent.

Monday: Mostly cloudy. Breezy. Frequent showers in the morning, then showers likely in the afternoon. Highs 74 to 80. Northeast winds 10 to 20 mph. Chance of rain 90 percent.

Monday Night: Mostly cloudy with scattered showers. Lows 58 to 71. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Breezy trades will deliver clouds and showers to windward and mauka areas through the week.

Discussion

A 1035mb high northwest of the islands combined with inversion heights around 6 kft this afternoon have caused winds to reach the Wind Advisory threshold in portions of Maui Countya nd the Big Island this morning into this afternoon. The advisory remains in good shape and remains in effect through 10pm HST this evening.
The high will weaken slightly tonight and Monday, but the gradient locally will remain quite strong keeping breezy trades in place. A front passing by to the north of the state and a weak trough moving in from the east should weaken the gradient Tuesday into Wednesday, easing the trades to moderate levels. A new strong high building north of the islands Thursday into next weekend, could bring a return of breezy trades to the state.
Moisture associated with an old front will remain in close proximity to Kauai through Monday keeping shower coverage the highest here, while drier trade wind weather prevails over the remainder of the state. The frontal remnants will push southward Monday night and Tuesday bringing an increase in shower coverage from Oahu to the Big Island with little change in the weather across Kauai. The band of enhanced moisture will then meander over the islands Tuesday night through Thursday, bringing periods of showery weather mainly to windward areas, although the trades will allow some showers to reach leeward communities at times as well, mainly overnight and during the early morning hours. The deepest moisture then lifts northward Friday and Saturday, allowing a more uniform distribution of showers to return to the island chain.

Aviation

Breezy to locally windy trades will persist through the several days, bringing passing low clouds and showers to windward and mountain areas statewide. Moisture in the vicinity of a weakening stationary front just north of the state will continue to deliver enhanced low clouds and showers to windward Kauai through Monday. Periods of MVFR, or even brief IFR conditions, can be expected in showers. Otherwise, VFR conditions will prevail. AIRMET Sierra may be needed later tonight as trade showers increase in coverage over windward areas.
AIRMET Tango remains in effect for low-level turbulence over and downwind of terrain due to the breezy to locally windy trades across the state.

Marine

Rough marine conditions are expected through Monday due to a combination of fresh to strong trade winds, rough seas, and a large north swell. Small Craft Advisory conditions are expected across all Hawaiian waters and will likely persist into Monday before gradually improving. Trade winds are forecast to ease slightly on late Monday and Tuesday, then rebuild by late Wednesday. Winds and seas should drop below Small Craft Advisory levels by Tuesday for most marine zones as the large north swell fades and the strong trades ease some.
Due to the strength and direction of this northerly swell (340-360 degrees), moderate to heavy harbor surges are anticipated to continue in north-facing harbors through at least tonight and possibly into Monday. A marine weather statement remains posted for this hazard.
The current large north swell will continue to produce warning level surf to most north and east facing shores through tonight, with advisory level surf expected for many west facing coastlines. Latest near-shore and offshore buoys suggest a gradual decline in surf tonight through the middle of the week. Surf should drop to advisory levels along north facing shores on Monday. A small long-period swell may give a slight boost to north and west shore surf late Thursday and Friday, with small surf then expected for next weekend.
A series of overlapping small south swells should bring a boost to south shore surf starting on Monday and continuing through the middle of the week. Surf should return to small mostly background levels Friday into next weekend.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 AM HST Monday for Niihau, Oahu North Shore, Olomana, Maui Windward West, Kauai North, Kauai East, Koolau Windward, Molokai Windward, Molokai North, Maui Central Valley North, Windward Haleakala, Big Island East, Big Island North.
High Surf Advisory until 6 AM HST Monday for Kauai Leeward, Waianae Coast, Maui Leeward West, Molokai West.
Wind Advisory until 10 PM HST this evening for Lanai Mauka, Kahoolawe, Maui Windward West, Maui Leeward West, Kohala, Lanai Windward, Lanai Leeward, Maui Central Valley North, Maui Central Valley South, South Haleakala, Big Island South, Big Island Southeast, Big Island North.
Small Craft Advisory until 6 AM HST Monday for all Hawaiian waters,

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