Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Mostly sunny. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 90 near the shore to around 78 above 3000 feet. Light winds. Chance of rain 40 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows 73 to 78 near the shore to around 64 above 3000 feet. Light winds. Chance of rain 20 percent.

Sunday: Mostly sunny. Highs around 90 near the shore to around 78 above 3000 feet. Northeast winds up to 10 mph shifting to the south in the afternoon.

South Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 87. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows 71 to 77. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs around 87. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Partly sunny with scattered showers. Highs 77 to 84 in the valleys to around 68 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows 64 to 69 in the valleys to around 59 above 4000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 77 to 84 in the valleys to around 68 above 4000 feet. East winds up to 10 mph. Chance of rain 40 percent.

North Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 89. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows 67 to 77. East winds up to 10 mph in the evening becoming light. Chance of rain 20 percent.

Sunday: Mostly sunny with isolated showers. Highs 80 to 89. East winds up to 15 mph. Chance of rain 20 percent.

East Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 88. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows 65 to 78. Northeast winds around 10 mph. Chance of rain 20 percent.

Sunday: Partly sunny in the morning then becoming mostly sunny. Isolated showers. Highs 80 to 88. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Rather dry trade wind weather will prevail through the weekend, with brief showers favoring mainly windward and mauka areas. The trade winds will increase slightly beginning late Sunday and become breezy Monday through Tuesday as the remnant trough of former Tropical Cyclone Fernanda passes by to the south of the state. Deep tropical moisture associated with Fernanda will move into the eastern islands late Sunday night, and spread to the rest of the state Monday and Monday night. Wet weather and locally heavy rainfall can be expected across windward areas, particularly windward Maui and the Big Island, with leeward portions of all islands seeing some rain as well. A drier and more typical trade wind pattern is expected Tuesday night through late next week.

Discussion

Currently at the surface, a 1033 mb high is centered around 1950 miles north-northeast of Honolulu, while the remnant trough of Greg is located around 875 miles southwest of Kauai and the remnant low of Fernanda is located around 875 miles east-southeast of the Big Island. The gradient locally continues to produce moderate trade winds in unsheltered areas early this morning. Infrared satellite imagery shows mostly clear to partly cloudy conditions in most areas. Radar imagery shows isolated to scattered showers moving into windward areas, with a few decaying showers or a few sprinkles reaching leeward areas at times. Main forecast focus continues to revolve around the potential for some heavier rainfall associated with the remnants of Fernanda early next week.
Moderate trade winds will hold in place through the weekend, with a slight increase expected late Sunday as the remnant trough of former Tropical Cyclone Fernanda approaches from the east. The trades will strengthen to breezy levels Monday and Tuesday as the remnant trough of Fernanda slides by to the south of the state, then hold at breezy levels through late next week as strong high pressure builds to the distant north-northeast.
As for the remaining weather details, very little change to the overall weather forecast is expected during the next couple days, with rather dry trade wind weather prevailing. There will be some light showers affecting windward and mauka areas, particularly at night and during the early morning hours each day, with mostly dry conditions persisting in leeward locales.
The persistent dry pattern we've been experiencing for quite some time appears to come to an abrupt halt beginning late Sunday night over the eastern end of the state as deep tropical moisture associated with the remnant trough of Fernanda moves in. The deep tropical moisture will spread westward across the state Monday and Monday night. Periods of wet weather with locally heavy rainfall can be expected in windward areas as the remnants of Fernanda move through, and even leeward communities will see some rainfall, although the rain shadowing effects of the terrain should limit rainfall totals here. The deepest moisture and highest chances for heavy rainfall appear to be over windward sections of the Big Island and perhaps windward Maui at this time.
Drier conditions are forecast to move in from east to west across the island chain on Tuesday, with typical trade wind weather featuring brief windward and mauka showers and the occasional leeward spillover then prevailing Tuesday night through late next week.

Aviation

Mostly dry conditions, with scattered clouds favoring north through east sections of the islands, will persist through the weekend. Expect cloud cover to reform along the Kona slopes of the Big Island this afternoon before diminishing again tonight. Although a diurnal increase in shower activity is possible this morning across windward locations, VFR conditions will prevail through the forecast period for most locations. Moderate trade winds will continue through Sunday.
There are currently no AIRMETs, and none are anticipated at this time.

Marine

Surface high pressure moving far north and northeast of the islands will result in moderate to locally fresh trade winds through Sunday. The remnants of Fernanda will pass south of the islands Monday and this will help strengthen trades to generally fresh to locally strong magnitudes through the remainder of next week. This will likely prompt Small Craft Advisories for the typical windier waters around Maui County and Big Island.
East-facing shore surf will remain below normal through the weekend due to lighter trades upstream of the state. Short period east wind wave swell generated by the remnants of Fernanda, along with long period east swell generated from Hurricane Hilary currently moving west of the southern tip of Baja California Sur, will likely increase eastern shore surf from Monday night through Wednesday. East-facing shore surf heights are forecast to peak out below surf advisory thresholds Tuesday night into Wednesday morning as this triple shot of locally-generated trade wind wave swell and swells from both Fernanda and Hilary arrive. South shore surf will remain small through the day with a small, medium period swell arriving early next week.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov