Photo Credit: Brendan Stephen

West Kaua’i

Today: Mostly sunny. Breezy. Highs around 87 near the shore to around 75 above 3000 feet. East winds up to 20 mph.

Tonight: Partly cloudy. Breezy. Lows 69 to 74 near the shore to around 60 above 3000 feet. East winds up to 20 mph shifting to the northeast 10 to 15 mph after midnight.

Sunday: Mostly sunny. Breezy. Highs around 87 near the shore to around 75 above 3000 feet. East winds up to 20 mph.

South Kaua’i

Today: Partly sunny. Breezy. Isolated showers in the morning. Highs around 84. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 67 to 73. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Sunday: Partly sunny. Breezy. Isolated showers in the morning. Highs around 84. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 74 to 81 in the valleys to around 65 above 4000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 60 to 65 in the valleys to around 55 above 4000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Sunday: Mostly cloudy. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 74 to 81 in the valleys to around 65 above 4000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

North Kaua’i

Today: Breezy. Partly sunny with isolated showers. Highs 77 to 86. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 63 to 73. East winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Breezy. Partly sunny with isolated showers. Highs 77 to 86. East winds up to 20 mph. Chance of rain 20 percent.

East Kaua’i

Today: Mostly cloudy with isolated showers. Highs 77 to 85. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows 61 to 74. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Mostly cloudy with isolated showers. Highs 77 to 85. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Breezy trade wind conditions will persist through next week. Clouds and showers will predominantly favor windward and mauka areas overnight into the morning as areas of moisture move through. An increase in windward shower coverage is possible from Monday night through midweek due to a mid- to upper-level disturbance drifting westward across the state. Some of these showers may briefly extend to the dry leeward areas of the smaller islands.

Discussion

Guidance remains consistent, showing a strong surface ridge north of the state throughout the upcoming week, possibly strengthening later on. This will sustain breezy easterly trade winds with clouds and mostly brief showers favoring windward and mauka locations. The trade wind inversion will be situated between 6,000 and 7,500 feet, and precipitable water (PW) levels will generally range from 1.0 to 1.25 inches. Rainfall amounts will likely be limited, even in windward areas, except possibly during the first half of the week when an upper-level trough moves westward across the state, drawing up more moisture.
Guidance indicates PW values increasing above average starting Monday night through Tuesday in the eastern part of the state, and later spreading to the western areas by Tuesday night into midweek. While most showers during this period will favor windward and mauka areas, some could reach leeward areas, especially Tuesday night into Wednesday. This pattern of occasional light showers in our typically dry leeward regions may persist into the latter part of next week as the pressure gradient tightens, resulting in brisk easterly trades across the islands.

Aviation

Moderate to locally breezy trade winds will continue. Clouds and light showers will favor east and northeast facing slopes and coasts. Isolated spillover showers are expected along leeward slopes of the smaller islands, especially in the late night and morning hours.
A weak eddy just west of the Big Island is keeping the leeward coast and adjacent waters of the Big Island south of Hilo shrouded in occasional VFR cloudiness. Clouds should lift and dissipate after sunrise.
AIRMET Sierra remains in effect for mountain obscuration along windward slopes of the Big Island. Conditions are expected to improve by late morning. Elsewhere, VFR conditions will prevail except for brief MVFR CIG or VIS in passing showers.

Marine

A high pressure ridge north of the islands will keep moderate to strong trade winds blowing across the Hawaii region. A Small Craft Advisory (SCA) remains in effect for the windier channels and waters around Maui County and the Big Island through the weekend. This SCA for the windier waters may continue into much of next week.
The High Surf Warning (HSW) was extended through this afternoon as long period south swell heights in the 5 to 6 foot range continues to show up in this mornings southern offshore buoy observations. A gradual downward trend is expected starting tonight to High Surf Advisory levels lasting through Sunday. Only background small, medium to long period, south to southeast swell energy will move into the region for the rest of next week.
North shore surf will remain small for the next few days. Small medium period northwest pulses may provide a tiny bump from Sunday night into middle of next week. Surf along east shores will remain small and choppy each day due to continued trade winds.

HFO Watches/Warnings/Advisories

High Surf Warning until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.
Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov