Photo Credit: Brendan Stephen

West Kaua’i

Today: Mostly sunny with isolated showers. Highs around 90 near the shore to around 78 above 3000 feet. Northeast winds up to 10 mph shifting to the south in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 70 to 75 near the shore to around 61 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 20 percent.

Sunday: Breezy. Mostly sunny with isolated showers. Highs around 90 near the shore to around 78 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 87. Northeast winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 68 to 74. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Sunday: Mostly sunny. Breezy. Isolated showers in the morning, then scattered showers in the afternoon. Highs around 87. Northeast winds 10 to 20 mph. Chance of rain 40 percent.

Kaua’i Mountains

Today: Partly sunny with scattered showers. Highs 77 to 84 in the valleys to around 68 above 4000 feet. 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 61 to 66 in the valleys to around 56 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Sunday: Breezy. Partly sunny with scattered showers. Highs 77 to 84 in the valleys to around 68 above 4000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

North Kaua’i

Today: Partly sunny with scattered showers. Highs 80 to 89. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 74. East winds up to 15 mph shifting to the southeast after midnight. Chance of rain 40 percent.

Sunday: Partly sunny with scattered showers. Highs 80 to 89. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 40 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 80 to 88. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 75. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Sunday: Partly sunny with scattered showers. Highs 80 to 88. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Detailed Forecast

Synopsis

Fairly typical trade wind weather featuring mainly windward and mauka showers is expected through the middle next week. The trades will be on the increase today and tonight as a high builds to the distant northwest, with moderate to breezy conditions expected Sunday through the middle of next week. The trades could weaken for the tail end of the upcoming work week as a front approaches from the northwest, with the potential for an increase in showers late in the week and into next weekend as the remnant trough of tropical cyclone Jova approaches the island chain from the east.

Discussion

Currently at the surface, a weak trough of low pressure is positioned around 550 miles north-northeast of Honolulu, while a 1027 mb high is centered around 1500 miles northwest of Kauai. The trough to the north continues to cut off the stronger gradient associated with the high, keeping the trades weaker and in the light to moderate range. Infrared satellite imagery shows partly to mostly cloudy conditions in windward and mauka areas, and clear to partly cloudy skies in leeward locales. Meanwhile, radar imagery shows scattered showers moving into windward slopes and coasts, with the occasional shower spilling over into leeward communities. Main short term focus revolves around trade wind trends and rain chances.
The trough north of the islands will dampen out and shift slowly westward today while a building high to the distant northwest moves closer to the island chain. As a result, the trades are expected to strengthen back to moderate and locally breezy levels from east to west across the island chain. The high will remain anchored northwest of the state tonight through the middle of next week, keeping moderate to breezy trades blowing. A front approaching from the northwest and the remnant trough of tropical cyclone Jova approaching from the east, should then ease the trade winds back into the light to moderate range for the tail end of the upcoming work week.
As for the remaining weather details, fairly typical trade wind weather will prevail through the middle of next week, with bands of clouds and showers moving through the islands from time to time, favoring primarily windward and mauka locations, with the occasional showers reaching leeward communities. We could see an increase in trade wind showers toward the tail end of the upcoming work week, but more likely next weekend in association with the remnant trough of tropical cyclone Jova nearing the islands.

Aviation

Light to moderate trade winds will become moderate to locally breezy later today and persist into Sunday. Clouds and isolated to scattered showers will generally favor windward and mauka areas. Overall, VFR conditions will prevail with occasional MVFR conditions in the passing showers.
No AIRMETs are in effect.

Marine

Surface high pressure far northwest of the state will push southeastward over the next few days as a ridge builds north of the state. This will reinforce the local pressure gradient and gradually increase the trade wind speeds into the moderate to locally strong range through the first half of next week. A Small Craft Advisory (SCA) for the typical windy waters around Maui County and the Big Island has been issued starting this morning through Tuesday afternoon.
Surf along south facing shores will remain tiny today, before a small, long period south swell is expected to fill in Sunday and peak Monday slightly above the summer time average before gradually declining during the middle of next week.
Strengthening trade winds will help to boost wind wave driven choppy surf heights by Sunday. A small to moderate, long period easterly swell from Hurricane Jova in the East Pacific could push up surf along east facing shores early next week. A High Surf Advisory (HSA) for east facing shores is not expected at this time. No other significant swells are expected.

HFO Watches/Warnings/Advisories

Small Craft Advisory from 6 AM this morning to 6 PM HST Tuesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov