Photo Credit: Braden Jarvis

West Kaua’i

Today: Breezy. Mostly sunny with isolated showers. Highs around 87 near the shore to around 75 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 70 near the shore to around 60 above 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny with isolated showers. Highs around 88 near the shore to around 76 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 around 84. East winds 10 to 20 mph. Chance of rain 50 percent.

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

Tuesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 81 to 88. East winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered 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 70 percent.

Tonight: Breezy. Mostly cloudy with numerous showers. Lows 64 to 69 in the valleys to around 58 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 74 to 83 in the valleys to around 67 above 4000 feet. East winds 10 to 20 mph. Chance of rain 60 percent.

North Kaua’i

Today: Partly sunny. Breezy. Numerous showers in the morning, then isolated showers in the afternoon. Highs 77 to 86. East winds up to 20 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 64 to 73. East winds 10 to 15 mph. Chance of rain 70 percent.

Tuesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 77 to 88. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 77 to 85. East winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 65 to 75. East winds 10 to 15 mph. Chance of rain 50 percent.

Tuesday: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 73 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

A high pressure ridge will remain locked in place north of the Hawaii region through the rest of this week. A weak upper low drifting over the state into Tuesday will help produce periods of showers mainly over the windward and mountain areas in the overnight to early morning hours. The ridge to the north will strengthen from Wednesday onward, producing breezy to locally windy trade winds into next weekend.

Discussion

Radar imagery this morning shows scattered to numerous showers developing over and upstream of windward mountain ranges. Satellite imagery shows a band of low level clouds upstream of each island, moving into the windward slopes. This cloud band and a weak upper level low shown on the water vapor satellite channel will likely spread periods of showers along the windward and mountain slopes through the early morning hours. The weak upper level low continues to lift trade wind inversion heights this morning to around 7,000 feet at both Lihue and Hilo upper air observation sites. Temperature inversion heights at this level will support continued periods of trade wind showers favoring the windward and mountain areas through early Tuesday morning. This shower activity will decrease slightly during the mid morning to afternoon hours.
A subtropical high pressure ridge north of the Hawaiian Islands will produce moderate to breezy trade winds lasting through Tuesday. A slight increase in the easterly trade winds into the breezy to locally windy range will start on Wednesday and continue into next weekend as the ridge north of the islands strengthens. A cloud band from the likely remnants of an old East Pacific front may roll through the islands by Saturday, enhancing shower activity a bit for next weekend.
Otherwise little changes are forecast in the day to day island weather pattern with just more typical trade wind weather continues through the end of this week.

Aviation

Breezy easterly trades will continue, with clouds and showers favoring windward and mauka locations. Periods of MVFR conditions will continue over these windward sections through the morning hours. Otherwise, VFR conditions will prevail.
AIRMET Sierra for tempo mountain obscuration is in effect for most windward areas. Conditions should improve by mid morning.

Marine

Surface high pressure will remain north-northeast of the area, then gradually strengthen during the second half of the week. As a result, the trades will become fresh to locally strong, with near-gale winds in the Alenuihaha Channel and waters south of the Big Island beginning Wednesday. The Small Craft Advisory (SCA), currently in effect for the normally windier areas around Maui County and the Big Island, will likely continue through the week, with an expansion to include the waters around Kauai and Oahu on Wednesday.
Surf along south facing shores will continue to slowly decline as the south swell fades today. For the rest of the week, expect only background small, medium to long period, south to southeast swell energy moving through the local waters.
North shore surf is expected to be small through the week, coming from small, mainly medium-period, northwest swells. Surf along east shores will become increasingly rough and choppy from Wednesday onward as the trade winds strengthen across the state.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov