Photo Credit: Jason Weingardt

West Kaua’i

Today: Breezy. Partly sunny with isolated showers. Highs around 86 near the shore to around 74 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows around 70 near the shore to around 60 above 3000 feet. East winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 20 percent.

Friday: Mostly cloudy with isolated showers. Highs around 86 near the shore to around 73 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 85. East winds 10 to 20 mph. Chance of rain 50 percent.

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

Friday: Mostly cloudy with scattered showers. Highs 78 to 85. East winds around 15 mph. Chance of rain 40 percent.

Kaua’i Mountains

Today: Mostly cloudy. Showers likely in the morning, then scattered showers in the afternoon. Highs 73 to 82 in the valleys to around 64 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 68 in the valleys to around 57 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Friday: Mostly cloudy with scattered showers. Highs 73 to 80 in the valleys to around 64 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

North Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 75 to 86. Southeast winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 72. Southeast winds up to 15 mph increasing to 10 to 15 mph after midnight. Chance of rain 50 percent.

Friday: Mostly cloudy with scattered showers. Highs 75 to 86. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly cloudy with scattered showers. Highs 71 to 82. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 74. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday: Mostly cloudy with scattered showers. Highs 71 to 82. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Moderate to breezy easterly trade winds will linger over the islands through the upcoming weekend. Clouds and showers will favor typical windward and mauka areas.

Discussion

Aside from some scattered showers over the Oahu and Kauai leeward waters; satellite and radar imagery continues to show low clouds and showers over mainly windward and mauka areas with patchy high clouds across the region early this morning. As expected, winds across the state have turned easterly overnight as the trough west of Kauai moves further away and the 1036 mb high currently 1300 miles north-northeast of Honolulu slowly drifts west.
Not much has changed with the forecast through the upcoming weekend. Moderate to breezy easterly trades will continue into the weekend as a series of reinforcing highs build to our north. Guidance continues to show drier air filtering into the region over the next couple of days resulting in a stable trade wind pattern. Expect mainly windward and mauka showers, with showers increasing in intensity and coverage during the overnight and early morning hours. A few of these showers may briefly spill over into leeward areas.
The biggest change to the forecast revolves around the evolution of the trough to the west of Kauai over the weekend. Guidance now shows the trough somewhat lingering in the region through early next week. This may cause the winds over the western end of the state to weaken slightly and become more southeasterly by early next week resulting in localized land/sea breezes across sheltered leeward areas of Oahu and Kauai. Otherwise, expect windward and mauka showers to continue through next week under moderate to locally breeze east to southeast winds.

Aviation

Moderate to breezy easterly trade winds will blow across the Hawaiian Islands today. Isolated to scattered showers today will favor the windward slopes. Brief MVFR conditions are possible in moderate showers.
AIRMET Sierra for mountain obscuration remains in effect for windward areas of Kauai, Oahu, Maui and the Big Island. Low cloud ceilings should decrease in coverage later this morning leading to cancelling this AIRMET for most of the affected areas.

Marine

High pressure will gradually build westward well to the north of the state through Friday, strengthening the trade winds across the island chain. Fresh to strong trade winds over the eastern end of the state will expand westward over the Oahu and Kauai waters today and hold at those levels through Friday. A Small Craft Advisory is now in effect for most waters around Maui and the Big Island through 6 AM Friday, and for the windier areas through 6 PM Saturday.
A trough of low pressure will amplify to the west of the islands this weekend and linger into early next week. This may ease the trades and shift them around to a more east-southeasterly direction over the western end of the state, while moderate to strong easterly trades prevail over the eastern waters.
South shore surf will remain small and below the summertime average through the middle of next week, with only small inconsistent pulses of southwest swell expected. The next significant south-southwest swell appears to move in late next week.
East shore surf will remain near the seasonal average through Friday. A slight decrease is expected this weekend through the middle of next week as the trades ease over and upstream of the islands. Surf along north shores will remain very small with a slight bump possible late Sunday through Monday.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Friday for Maui County Windward Waters, Big Island Windward Waters.
Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov