West Kaua’i

Today: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 81 near the shore to around 70 above 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 68 near the shore to around 58 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 81 near the shore to around 68 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

South Kaua’i

Today: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 74 to 82. East winds 15 to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then numerous showers after midnight. Lows around 68. East winds 15 to 20 mph. Chance of rain 70 percent.

Saturday: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 74 to 80. East winds 15 to 20 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 70 to 76 in the valleys to around 61 above 4000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.

Tonight: Breezy. Scattered showers in the evening, then occasional showers after midnight. Lows 59 to 67 in the valleys to around 57 above 4000 feet. East winds 10 to 25 mph. Chance of rain near 100 percent.

Saturday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 70 to 75 in the valleys to around 60 above 4000 feet. East winds 15 to 25 mph. Chance of rain 70 percent.

North Kaua’i

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 72 to 81. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers in the evening, then mostly cloudy with numerous showers after midnight. Lows 61 to 69. East winds 10 to 15 mph. Chance of rain 70 percent.

Saturday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 71 to 80. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 69 to 79. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Scattered showers in the evening, then occasional showers after midnight. Lows 62 to 72. East winds 10 to 15 mph. Chance of rain near 100 percent.

Saturday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 68 to 79. East winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Trade winds will continue into next week, bringing showers to the usual windward areas. Winds will increase over the weekend as a new high strengthens north of the islands.

Discussion

No significant changes to the forecast this morning. The forecast has been updated with the latest National Blend of Models solution, which is very similar to the previously issued forecast. High pressure to the northeast is maintaining a breezy trade wind pattern over the islands. Winds should decrease a bit today as the high weakens. However winds will be on the uptick once again over the weekend as a new high moves far north of the islands and strengthens.
With the trade wind pattern, expect clouds and showers to be focused over the windward sides of the islands. As trades increase this weekend, some of the showers could reach leeward locations.
An upper level trough to the west of the islands will move towards the islands and weaken. By Sunday this upper level features is expected to weaken and be near the islands, and could enhance some of the trade wind showers. As this feature washes out, we will return to a more typical trade wind shower pattern.
The GFS is more progressive than the ECMWF with a front/trough moving towards the islands from the northwest next week. The GFS solution would have the boundary near Kauai Wednesday night, while the ECMWF could still have it to the northwest of Kauai at that time. Will continue to monitor this feature in future model runs.

Aviation

High pressure northeast of the islands will maintain a breezy trade wind pattern through the weekend. Clouds and showers riding in on the trade winds will bring passing MVFR conditions mostly to windward locations, while leeward areas are expected to remain VFR.
AIRMET Sierra is in effect for mountain obscuration for Kauai, and Oahu for windward sections due to ongoing showers and low ceilings. Conditions improved overnight over the islands of Maui County and the Big Island, and improvement over Kauai and Oahu is expected today.
AIRMET Tango remains in effect for moderate turbulence below 7 kft for leeward sides of the islands. Conditions are expected to persist for the next several days.

Marine

Strong high pressure building far north of the waters will continue to drift east supporting moderate to strong easterly trade winds and elevated seas into next week. Winds look to maintain strong speeds but veer slightly early next week as high pressure continues to tracks east and a potential disturbance may develop to the west northwest of the islands too. A Small Craft Advisory (SCA) has been extended for all coastal water zones through Saturday night due to a combination of winds and seas reaching criteria during the next 48 hours.
A small to moderate medium to long period northwest swell will continue to build through the day and peak late tonight into Saturday below High Surf Advisory (HSA) levels, before declining through the weekend. Looking into next week, small background northwest swell energy is expected through the forecast period.
Surf along east facing shores will continue to build over all waters into this weekend and early next week due to persistent strong trades locally and upstream of the islands. A HSA is likely for east facing shores over the weekend.
Surf along south shores remains small with some background trade wind swell for select exposures.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Sunday for All Hawaiian Coastal Waters.

Data Courtesy of NOAA.gov