Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 89 near the shore to around 77 above 3000 feet. East winds up to 20 mph. Chance of rain 40 percent.

Tonight: Partly cloudy with isolated showers. Lows 71 to 76 near the shore to around 62 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Monday: Breezy. Mostly sunny with isolated showers. Highs around 89 near the shore to around 77 above 3000 feet. East winds up to 20 mph. Chance of rain 20 percent.

South Kaua’i

Today: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 86. Northeast winds 15 to 20 mph. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Breezy. Scattered showers. Lows 69 to 75. Northeast winds 15 to 20 mph. Chance of rain 40 percent.

Monday: Breezy. Partly sunny with isolated showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs around 86. East winds 15 to 20 mph. Chance of rain 40 percent.

Kaua’i Mountains

Today: Partly sunny. Breezy. Scattered showers in the morning, then numerous showers in the afternoon. Highs 76 to 83 in the valleys to around 67 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 62 to 67 in the valleys to around 57 above 4000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Monday: Breezy. Partly sunny with scattered showers. Highs 76 to 83 in the valleys to around 67 above 4000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

North Kaua’i

Today: Mostly sunny with scattered showers in the morning, then partly sunny with numerous showers in the afternoon. Highs 79 to 88. East winds up to 15 mph. Chance of rain 70 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 65 to 75. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 40 percent.

Monday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 79 to 88. East winds up to 20 mph. Chance of rain 40 percent.

East Kaua’i

Today: Partly sunny. Scattered showers in the morning, then numerous showers in the afternoon. Highs 79 to 87. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 76. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Monday: Partly sunny with scattered showers. Highs 79 to 87. East winds 10 to 15 mph. Chance of rain 40 percent.

Detailed Forecast

Synopsis

High pressure northwest of the state will support moderate to breezy trade winds through the middle of the week. Fairly typical trade wind weather is expected during this time, with mainly windward and mauka showers and the occasional leeward spillover. The trades are expected to ease for the tail end of the upcoming work week into next weekend, with the potential for an increase in showers as a disturbance aloft pivots southward over the islands, while the remnant trough of tropical cyclone Jova approaches from the east.

Discussion

Currently at the surface, a 1027 mb high is centered around 1300 miles north-northwest of Kauai, with a 1022 mb high around 1650 miles northeast of Honolulu. The resulting gradient is producing moderate trade winds across the island chain early this morning. Infrared satellite imagery shows partly to mostly cloudy conditions in windward areas, with clear to partly cloudy skies in most leeward locales. Meanwhile, radar imagery shows scattered showers moving into windward slopes and coasts, with some of these showers spilling over into leeward communities. Main short term focus revolves around trade wind trends and rain chances.
The high to the distant northwest will remain anchored northwest of the state through the middle of the week, keeping moderate to breezy trades blowing across the island chain. A front approaching from the northwest and the remnant trough of tropical cyclone Jova approaching from the east, should ease the trade winds back into the light to moderate range for the tail end of the upcoming work week and into next weekend.
As for the remaining weather details, fairly typical trade wind weather will prevail through the middle of the week, with bands of clouds and showers moving through the islands from time to time, favoring primarily windward and mauka locations, with the occasional shower reaching leeward communities. We could see an increase in trade wind shower coverage and intensity toward the tail end of the upcoming work week and into next weekend, as troughing aloft pivots southward over the state, while the remnant trough of tropical cyclone Jova approaches and eventually moves through the islands from east to west.

Aviation

Moderate to locally breezy trades will persist through twenty-four hours and beyond. Clouds and scattered showers will favor windward and mauka areas with isolated spillover showers impacting leeward areas at times. Brief MVFR ceilings and visibilities are possible in passing showers, otherwise VFR conditions will prevail statewide.
AIRMET TANGO for moderate low level turbulence remain in effect. Conditions are expected to persist through twenty-four hours and beyond.

Marine

A high far northwest of the main Hawaiian Islands will push southeastward over the next few days, strengthening the ridge north of the state. This will keep trade wind speeds in the moderate to locally strong range through the first half of the work week. A Small Craft Advisory (SCA) remains in effect for the typical windier waters around Maui County and the Big Island through Tuesday afternoon.
Surf along south facing shores will get a boost over the next few days as a small, long-period south swell fills in. The swell and surf are forecast to peak Monday slightly above the summer average, then gradually decline through the middle of the week.
Strengthening trade winds, along with a small to moderate, long- period east swell from Tropical Storm Jova in the East Pacific, will boost east shore surf heights through the middle of the week. A High Surf Advisory (HSA) for east facing shores is not expected at this time, but will continue to monitor the nearshore buoys as this swell unfolds.

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