Photo Credit: Jason Weingardt

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. Lows 69 to 74 near the shore to around 60 above 3000 feet. Northeast winds up to 15 mph.

Monday: 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. Northeast winds 15 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.

Monday: Partly sunny. Breezy. Isolated showers in the morning. Highs around 84. East 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 becoming 10 to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 60 to 65 in the valleys to around 55 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Monday: 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.

North Kaua’i

Today: Breezy. Partly sunny with isolated showers. Highs 77 to 86. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. 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.

Monday: 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. Northeast 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.

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

Detailed Forecast

Synopsis

Breezy trade wind conditions will persist through the 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 late Monday through midweek due to an upper 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 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 7,000 feet, and precipitable water (PW) levels will generally range from 1.0 to 1.25 inches. Rainfall amounts will remain limited, even in windward areas, except possibly during the first half of the week when an upper-level low drifts westward across the state, drawing up more moisture.
Guidance indicates PW values increasing 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 areas may persist into the latter part of the week as the pressure gradient tightens, resulting in brisk easterly trades across the islands.

Aviation

Moderate to locally breezy trades will continue at least through midweek. Low cigs and SHRA will favor windward and mauka zones. Brief periods of MVFR conds are possible. A few SHRA may make it to lee sides heading into Monday.
AIRMET Sierra is in effect for mtn obsc for windward Big Island.
AIRMET Tango is in effect for low level turb lee of terrain due to gusty trade winds.

Marine

A high pressure ridge north of the islands will keep moderate to strong trade winds blowing across the Hawaii region. The ridge north of the state will strengthen from Wednesday onward with increasing wind speed trends in the easterly trades. A Small Craft Advisory (SCA) remains in effect for the windier channels and waters around Maui County and the Big Island through Monday. This SCA for these windier waters will likely continue through the week, expanding in coverage from Wednesday onward.
Surf along south facing shores has fallen below High Surf Advisory levels this morning. Surf heights will continue to slowly decline as the south swell fades through Monday. Only background small, medium to long period, south to southeast swell energy will move into the region for the rest of the week.
North shore surf will see only small medium period northwest pulses providing a tiny increases through the week. Surf along east shores will remain small and choppy each day due to continued trade winds.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Monday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov