West Kaua’i

Tonight: Partly cloudy. Isolated showers in the evening. Lows 71 to 76 near the shore to around 62 above 3000 feet. Light winds becoming northeast up to 10 mph after midnight. Chance of rain 20 percent.

Friday: Mostly sunny. Isolated showers in the afternoon. Highs 87 to 94 near the shore to around 79 above 3000 feet. East winds up to 10 mph. Chance of rain 20 percent.

Friday Night: Mostly cloudy. Lows around 74 near the shore to around 62 above 3000 feet. East winds around 10 mph.

South Kaua’i

Tonight: Partly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows around 74. Northeast winds around 10 mph. Chance of rain 30 percent.

Friday: Mostly sunny with isolated showers. Highs 84 to 92. East winds 10 to 15 mph. Chance of rain 20 percent.

Friday Night: Mostly cloudy with isolated showers. Lows around 75. East winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Tonight: Mostly cloudy with scattered showers. Lows 65 to 71 in the valleys to around 60 above 4000 feet. East winds around 10 mph. Chance of rain 50 percent.

Friday: Mostly sunny with scattered showers in the morning, then partly sunny with isolated showers in the afternoon. Highs 77 to 86 in the valleys to around 70 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Friday Night: Mostly cloudy. Scattered showers in the evening, then isolated showers after midnight. Lows 66 to 71 in the valleys to around 61 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

North Kaua’i

Tonight: Partly cloudy with scattered showers. Lows 66 to 74. East winds around 10 mph. Chance of rain 40 percent.

Friday: Mostly sunny with isolated showers. Highs 80 to 89. East winds 10 to 15 mph. Chance of rain 20 percent.

Friday Night: Mostly cloudy. Isolated showers in the evening. Lows 66 to 76. East winds 10 to 15 mph. Chance of rain 20 percent.

East Kaua’i

Tonight: Mostly cloudy with scattered showers. Lows 66 to 78. Northeast winds around 10 mph. Chance of rain 40 percent.

Friday: Mostly sunny with isolated showers. Highs 76 to 89. East winds 10 to 15 mph. Chance of rain 20 percent.

Friday Night: Mostly cloudy with isolated showers. Lows 67 to 79. East winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Light trades continue through tonight as a low-level trough north of the islands moves west. High pressure will build back in across the region Friday into early Sunday bringing the return of moderate to locally breezy trade winds. Another brief increase in clouds and showers will develop Sunday afternoon into Monday as another low-level trough (remnants of former Tropical Cyclone Ivo) moves westward across the islands. Stable drying trends return beyond Tuesday.

Discussion

Regional satellite imagery shows a low-level trough northeast of the islands this afternoon. This has resulted in a hybrid sea breezy pattern setting up across the state, with radar imagery showing a few showers developing over sheltered leeward locations. Guidance continues to show this trough moving west tonight which will bring a slight increase in clouds and showers over windward and mauka areas, with any lingering activity over leeward areas dissipating this evening.
By Friday, a surface ridge will build north of the Hawaiian Islands allowing moderate to locally breezy trades to return. Drier air will filter in from the east as a very stable upper- level ridge nudges its way back over the state. This will bring lower trade wind inversion heights, with clouds and showers over mainly windward and mauka areas through Sunday morning.
By Sunday afternoon, yet another disturbance will move from east to west across the islands. This trough will have slightly different island by island impacts as deeper moisture and dynamics are associated with the remnants of former Tropical Cyclone Ivo. This trough will increase humidity levels across the state from Sunday afternoon through Monday. Inversion heights will lift to around 8,000 to 9.000 feet enhancing clouds and showers in a moderate trade wind weather pattern. Confidence in this brief period of enhanced shower activity is only fair at the moment. Typically these remnant tropical systems tend to be compact in size and may possibly track a bit further north than currently predicted. If this system does move further north then our current weather forecast will change, resulting in less clouds and showers reaching the Hawaiian Islands. Stay tuned for further updates.
A high pressure ridge will swiftly build back into the region on Tuesday, just as the remnant trough continues on its westward journey away from the state. This returning ridge will bring strong stable trends with drier humidity levels, and a return to more typical dry summer weather across the state through the middle of next week.

Aviation

Light trades have given way to a hybrid sea breeze pattern this afternoon with flow directed increasingly onshore depending on the degree of sheltering. Limited afternoon showers over leeward zones will diminish with the loss of heating this evening. Trades then gradually strengthen during Friday with any shower activity focused windward and mauka.
No AIRMETs in effect.

Marine

Surface trough moving westward north of the waters will keep light to locally moderate flow through tonight. Trade winds will gradually strengthen Friday into the weekend as the high builds north of the state. A Small Craft Advisory for the windier waters and channels around Maui County and the Big Island could start as early as Friday morning and hold through the weekend.
Surf along south facing shores will remain small through tonight with mainly background medium to long period energy. Surf should see a slight bump early Friday and hold through early next week as a series of small long period southerly energy fills in.
A small, medium period northeast swell will keep surf along east facing shores elevated through the weekend. As this swell declines, the short period energy will fill in as trade winds increase into the weekend. North facing shores will remain flat to tiny through the forecast period except for areas that may be exposed to the small northeast swell.

Fire weather

Weather conditions should remain below critical fire weather thresholds into early next week. A low-level trough north of the islands will continue to move westward tonight producing a slight increase in clouds and showers. Another low-level disturbance associated with the remnants of former Tropical Cyclone Ivo will likely increase humidity levels and shower trends on Sunday and Monday. A return to lower humidity levels will develop by Tuesday as a stable upper-level ridge builds back over the island chain.

HFO Watches/Warnings/Advisories

None.

Kauai Now Weather is brought to you by Blue Hawaiian Helicopters.