Photo Credit: Sebastien Gabriel

West Kaua’i

Today: Mostly sunny. Breezy. Highs around 88 near the shore to around 77 above 3000 feet. East winds up to 20 mph.

Tonight: Partly cloudy. Lows around 70 near the shore to around 60 above 3000 feet. East winds up to 15 mph shifting to the northeast after midnight.

Saturday: Sunny and breezy. Highs around 88 near the shore to around 76 above 3000 feet. East winds up to 20 mph.

South Kaua’i

Today: Breezy. Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 81 to 87. East winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows around 71. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Saturday: Breezy. Mostly sunny with isolated showers. Highs 82 to 88. East winds 10 to 20 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Partly sunny with scattered showers. Highs 74 to 84 in the valleys to around 67 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 69 in the valleys to around 58 above 4000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 74 to 83 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 in the morning, then mostly sunny with isolated showers in the afternoon. Highs 77 to 88. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows 64 to 73. East winds 10 to 15 mph. Chance of rain 20 percent.

Saturday: Breezy. Mostly sunny with isolated showers. Highs 77 to 89. East winds up to 20 mph. Chance of rain 20 percent.

East Kaua’i

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 73 to 85. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy with isolated showers after midnight. Lows 65 to 75. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Mostly sunny with isolated showers. Highs 74 to 85. East winds 10 to 15 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A high pressure ridge will linger north of the Hawaiian Islands into next week producing moderate to breezy trade winds. Weak upper level troughing will keep brief periods of windward showers in the forecast favoring windward and mountain areas with drier conditions over leeward locations. Clouds and showers will develop along the Kona slopes of the Big Island each afternoon and evening.

Discussion

A combination of satellite and radar imagery this morning shows numerous light to moderate showers moving into the eastern slopes of the Big Island and Maui. Smaller islands show more isolated to scattered shower coverage. Weak upper level troughing will continue to keep brief periods of showers in the forecast. However, a weak low level easterly wave moves into the islands by Saturday night as shown on the 700 mb streamlines, producing a slight boost to shower activity through Sunday morning. A subtropical jet stream over the region will continue to spread high level ice crystal cirrus clouds from west to east across the islands. These clouds will likely enhance morning sunrise and evening sunset colors through the weekend.
A high pressure ridge will linger through this weekend and into next week. This ridge will maintain a fairly typical moderate to breezy trade wind weather pattern into the foreseeable future with little day to day variation. Weak upper level troughing will keep the trade wind temperature inversion heights between 5,000 to 7,000 feet for much of the forecast period. Expect brief showers at times, mainly over windward and mountain areas. Shower activity will trend higher in the overnight to early morning hours each day. Drier conditions are forecast over leeward locations.
Not much day to day change in the weather forecast is expected over the next seven days. Increasing trends in the easterly trade wind speeds may develop from next week Wednesday onward.

Aviation

With a ridge north of the islands, expect moderate to breezy trade winds to continue over the next couple of days. Low clouds and showers will favor windward and mauka areas, and will bring brief periods of MVFR conditions. A few showers may make it over to leeward areas at times, but otherwise, VFR conditions should prevail. An enhanced area of clouds and showers riding in on the trades upstream of the Big Island early this morning will continue to bring MVFR conditions to the east side through mid morning.
AIRMET Sierra has been posted for tempo mountain obscuration on the Big Island. Expect conditions to improve later today. No other AIRMETs are in effect at this time.

Marine

Fresh to locally strong easterly trades will continue through the weekend much of next week as a surface ridge remains north of the area. A Small Craft Advisory (SCA) remains in effect for the windier channels and waters around Maui County and the Big Island through Saturday and will likely be extended later today through the weekend. The ridge may weaken a touch early next week, that could ease winds to moderate to locally strong, however the SCA for the windier waters may continue through the forecast period.
Near shore buoys continue to show a small to medium, long period south swell filling quite nicely. A High Surf Advisory has been posted for all south facing shores today as this long period south swell continues to gradually build today. This swell could reach near warning- levels late tonight and Saturday as the swell peaks. Offshore buoy 51004 has been showing slightly more swell energy than buoy 51003 which could mean the bigger portion of the swell is farther east than expected. We will continue to monitor all observations to determine if the HSA needs to be upgraded to a High Surf Warning. A gradual downward trend is expected Sunday into early next week. After this swell moves out, very little swell is expected next week beginning around Tuesday. North- facing shore surf will become flat for the next few days. Small medium period northwest pulses may provide a tiny bump Sunday night into middle of next week. Surf along east- facing shores will remain small and choppy each day due to a limited trade wind fetch upstream of the islands.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Saturday for south facing shores.
Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov