Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 91 near the shore to around 79 above 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 73 to 78 near the shore to around 64 above 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Sunday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 91 near the shore to around 79 above 3000 feet. East winds up to 10 mph. Chance of rain 50 percent.

South Kaua’i

Today: Partly sunny with scattered showers. Highs around 88. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 71 to 77. Northeast winds around 10 mph. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers. Highs around 88. East winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 78 to 85 in the valleys to around 69 above 4000 feet. East winds 10 to 15 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy. Numerous showers in the evening, then frequent showers after midnight. Lows 64 to 69 in the valleys to around 59 above 4000 feet. East winds 10 to 15 mph. Chance of rain 60 percent.

Sunday: Mostly cloudy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 78 to 85 in the valleys to around 69 above 4000 feet. East winds 10 to 15 mph. Chance of rain 60 percent.

North Kaua’i

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 81 to 90. East winds 10 to 15 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 67 to 77. East winds around 10 mph. Chance of rain 60 percent.

Sunday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 81 to 90. East winds 10 to 15 mph. Chance of rain 60 percent.

East Kaua’i

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 81 to 89. East winds 10 to 15 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 65 to 78. Northeast winds around 10 mph. Chance of rain 60 percent.

Sunday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 81 to 89. East winds 10 to 15 mph. Chance of rain 60 percent.

Detailed Forecast

Synopsis

Trade winds will ease slightly through the weekend as the driving high to the north weakens. Expect clouds and showers to favor windward and mauka locations at night and during early morning hours, with some showers spilling over to leeward areas. Shower and cloud coverage may increase slightly over the next couple of days as an upper disturbance moves over the state.

Discussion

High pressure persists far north of the main Hawaiian Islands. However, upper troughing has put a damper on the effect this high has on local trade wind strength. While a Small Craft Advisory remains for the Alenuihaha Channel this morning, only moderate trade winds dominate elsewhere. Current radar and satellite loops show scattered to broken low clouds, with moderate to locally heavy showers, riding in with the trades near the smaller islands. These will favor windward areas there. Cloud cover is more pervasive around and across the Big Island, where broken to overcast low clouds across windward shores and slopes wrap around to Kona and Kau shores and slopes. Inversion heights from overnight soundings were around 8400 feet, enhancing showers and increasing shower coverage to include some leeward areas.
An upper trough will destabilize our airmass a bit this weekend. This, combined with the high weakening to our north, may trigger a subtle increase in windward cloud and shower coverage. Trade winds, already a bit weaker than yesterday, may decrease a bit more through Sunday. Models show this pattern persisting into early next week, followed by a return of drier air and strengthening easterly trades Tuesday through midweek as the high rebuilds north- northeast of the state.

Aviation

Moderate trade flow, along with a raised inversion height of 8 to 9 kft, will lead to scattered/numerous moderate to occasionally heavy showers over windward portions of the islands this morning. Isolated showers will likely continue to spill onto leeward locations. Brief periods of MVFR ceilings and visibility may accompany some of the more robust showers.
Shower activity is forecast to decrease slightly by late this morning and into the afternoon.
No AIRMETs are currently in effect.

Marine

High pressure north-northeast of the state will keep moderate to fresh trades through the weekend. The Small Craft Advisory (SCA) only includes the Alenuihaha Channel through this afternoon. Guidance shows high pressure restrengthening to the distant northeast Tuesday through the middle of next week, bringing trades back up into the fresh to locally strong range.
North and west shores remain flat through today with a small bump filling in Sunday evening through early next week as a small medium period northwest swell traverses area waters. The northwest swell will then fade out during the middle of next week.
Surf along east facing shores will remain tiny through early next week as local winds weaken slightly. Surf then trends up toward the summer average by the middle of next week as trades restrengthen.
Surf along south facing shores will remain small through Monday, with mainly background southerly swells moving through. This will be followed by a modest bump mid-week as medium-sized, long-period energy reaches the area.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST this evening for Alenuihaha Channel.

Data Courtesy of NOAA.gov