Photo Credit: Jason Weingardt

West Kaua’i

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 88 near the shore to around 76 above 3000 feet. East winds up to 10 mph shifting to the southwest in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy. Isolated showers after midnight. 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: Mostly sunny. Isolated showers in the morning. Highs around 88 near the shore to around 76 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 85. East winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Isolated showers. Lows 68 to 74. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Partly sunny with isolated showers in the morning, then mostly sunny in the afternoon. Highs around 85. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 75 to 82 in the valleys to around 66 above 4000 feet. East winds up to 10 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 66 in the valleys to around 56 above 4000 feet. Light winds. Chance of rain 50 percent.

Sunday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 75 to 82 in the valleys to around 66 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

North Kaua’i

Today: Partly sunny with scattered showers. Highs 78 to 87. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 74. Southeast winds up to 10 mph in the evening becoming light. Chance of rain 30 percent.

Sunday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 78 to 87. East winds up to 15 mph. Chance of rain 30 percent.

East Kaua’i

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 78 to 86. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 76. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 30 percent.

Sunday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 78 to 86. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 30 percent.

Detailed Forecast

Synopsis

Light to moderate trades will persist today, with a band of enhanced moisture bringing some showery weather to portions of the state this morning. Drier conditions are expected this afternoon, however sea breeze development will allow for a few showers to develop in leeward areas this afternoon. The trades will ramp back up tonight, then hold at moderate to breezy levels Sunday through Thursday. Rather dry conditions will prevail Sunday through Wednesday, with a trend toward more showery conditions late next week.

Discussion

Currently at the surface, a ridge of high pressure located around 225 miles north of Kauai is producing light trade winds with land breezes present in many areas across the island chain. Infrared satellite imagery shows mostly cloudy conditions across much of the state, with a few areas around the Big Island seeing a bit less cloud cover. Radar imagery shows scattered showers moving into windward areas, with the coverage highest from Oahu to Big Island where leeward areas are seeing some shower activity as well. Main short term focus revolves around trade wind trends and rain chances during the next couple days.
The ridge of high pressure north of the islands will remain nearly stationary today, keeping light to moderate trades in place and allowing some sea breeze development in leeward areas. The ridge will lift northward late today through the remainder of the weekend, allowing the trades to gradually increase to moderate and breezy levels by Sunday, and hold at these levels through much of next week.
As for the remaining weather details, an area of enhanced moisture will bring some showery weather to windward areas and send some of these showers into leeward locales through the morning hours today. Drier conditions should develop by afternoon, with a few showers developing over leeward terrain with the assistance of localized sea breezes. Rather dry conditions are then expected tonight through the middle of next week, with mid-level ridging and stronger trades keeping light showers confined primarily to windward and mauka areas. Mid-level ridging begins to break down late next week, which should bring an increase in trade wind showers to the island chain.

Aviation

Light to moderate easterly trade winds will persist through this afternoon. Flow should be light enough to bring nighttime land breezes and daytime sea breezes over each island. Clouds and showers will favor windward and mauka areas through the period, with some afternoon development over leeward interior areas. Brief MVFR ceilings and visibility will be possible in showers, especially over windward portions of the smaller islands, but expect VFR conditions to generally prevail at the TAF sites.
AIRMET Sierra is currently in effect for mountain obscuration above 2500 feet for north thru southeast sections of Kauai, Oahu, Molokai, and Maui.

Marine

Trades will steadily increase over the weekend as the surface ridge nearby lifts northward and strengthens. The strongest winds are expected over the windier waters and channels around Maui County and the Big Island beginning tonight, which will require a Small Craft Advisory. Little change in wind speed is expected through the first half of next week.
Surf along south-facing shores will remain up through Monday as a medium period south-southwest swell moves through. The nearshore and offshore buoy observations reflect this swell and show the peak energy holding within the 13-14 second bands this morning. A downward trend is expected Tuesday through midweek, with mainly background southerly energy expected. A similarly sized south- southwest swell is possible next weekend.
Surf along north and west-facing shores will trend up late Sunday through Monday as an out-of-season, small north-northwest swell arrives. This trend with small north-northwest pulses could persist through a good portion of the upcoming week due to broad low pressure positioned far north of the state near the Aleutians.
Surf along east-facing shores will pick up slightly later this weekend through early next week as the trades increase. Although confidence remains low being so far out in time, guidance is hinting at a medium- to long-period easterly swell arriving late next week through next weekend due to the uptick in tropical activity across the far eastern Pacific.
Higher-than-predicted water levels combined with near-peak monthly tides and a decent south swell moving through could lead to minor coastal flooding/runup impacts through the weekend. The best chance for coastal impacts will occur during the afternoon hours around the peak daily high tide cycles.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov