West Kaua’i

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 81 near the shore to around 68 above 3000 feet. East winds 10 to 25 mph. Chance of rain 40 percent.

Tonight: Breezy. Mostly clear with isolated showers. Lows around 69 near the shore to around 59 above 3000 feet. East winds 10 to 20 mph decreasing to up to 20 mph after midnight. Chance of rain 20 percent.

Sunday: Breezy. Sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 81 near the shore to around 69 above 3000 feet. East winds up to 20 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.

South Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 74 to 81. East winds 15 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 68. East winds 15 to 20 mph. Chance of rain 50 percent.

Sunday: Partly sunny. Breezy. Scattered showers in the morning, then numerous showers in the afternoon. Locally heavy rainfall possible in the afternoon. Highs 75 to 81. East winds 15 to 25 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Breezy. Partly sunny with scattered showers. Highs 69 to 76 in the valleys to around 61 above 4000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 60 to 67 in the valleys to around 57 above 4000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Sunday: Mostly cloudy. Windy. Scattered showers in the morning, then numerous showers in the afternoon. Highs 70 to 77 in the valleys to around 61 above 4000 feet. East winds 10 to 20 mph increasing to 10 to 30 mph in the afternoon. Chance of rain 70 percent.

North Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 72 to 81. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 62 to 70. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 50 percent.

Sunday: Breezy. Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 72 to 81. East winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Locally heavy rainfall possible in the morning. Highs 68 to 79. East winds 10 to 20 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 72. East winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Mostly cloudy. Breezy. Scattered showers in the morning, then numerous showers in the afternoon. Locally heavy rainfall possible in the afternoon. Highs 68 to 78. East winds 10 to 15 mph increasing to 15 to 25 mph in the afternoon. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Trade winds will continue into next week, bringing showers to the usual windward and mauka locations. A slight increase in showers is expected Sunday and Sunday night. Winds will increase through the weekend and into next week as the pressure gradient strengthens over the islands. Trade winds will become southeast Tuesday night and remain that way through the end of next week.

Discussion

Isolated showers are ongoing across most windward and mauka areas this morning. A trough is bringing in some upper level clouds from the south as evident on satellite imagery. Trade winds will continue through the weekend, and strengthen through Sunday. This should continue the windward and mauka showers that are typical in a trade wind regime. Winds will strengthen slightly and continue well into next week. An upper level trough approaching from the northwest around midweek appears strong enough to turn our surface winds to out of the southeast Tuesday night. Though is it forecast to weaken as it swings through the state it should be enough to keep our winds out of the southeast through the forecast period.

Aviation

Moderate to breezy easterly trade winds will prevail across the islands through the weekend and well into next week. Showers and occasional low clouds embedded within the trade wind flow will generally favor north through east sections of the islands throughout this period. While VFR flight conditions are expected to prevail at most locations today, a band of moisture moving into the state from the east early this morning is expected to increase windward and mountain shower activity, particularly over the eastern end of the state. Looking ahead, guidance continues to show an additional, more robust, band of showers moving into the islands on Sunday. This will likely lead to an increase in MVFR conditions across windward and mountain locations for most islands.
AIRMET Tango remains in effect for moderate turbulence downwind of island terrain. These conditions are expected to continue into the foreseeable future, as the breezy to strong trades will persist for several days. Additionally, AIRMET Sierra has been issued early this morning for mountain obscuration along north through east sections of Maui. This AIRMET may need to be expanded to include windward portions of other islands as well later this morning.

Marine

Strong high pressure far north of the state will continue to produce rough conditions into next week. Trade winds are expected to gradually strengthen through Sunday, where we could see gales over the windier waters and channels around Maui County. A Small Craft Advisory (SCA) has been extended for all coastal water due to a combination of winds and seas through Sunday night. A Gale Watch may be needed for the Alenuihaha Channel on Sunday and possibly the Pailolo Channel this afternoon.
The current small medium period northwest swell will continue to hold this morning before a gradual decrease expected through Sunday. Minimal energy is expected from the northwest during the first half of next week, although select exposures should see some wind swell.
Surf along east facing shores will continue to build over all waters into this weekend and early next week due to the persistent strong trades locally and upstream of the islands. Surf heights look to stay just below High Surf Advisory today but may reach criteria Sunday.
Surf along south shores remains small with some background trade wind swell for select exposures through the forecast period.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Monday for all Hawaiian waters,

Data Courtesy of NOAA.gov