Photo Credit: Braden Jarvis

West Kaua’i

Today: Sunny and haze. Highs 80 to 85 near the shore to around 72 above 3000 feet. Light winds.

Tonight: Mostly clear. Haze through the night. A 20 percent chance of showers after midnight. Lows 63 to 68 near the shore to around 54 above 3000 feet. Light winds becoming northeast up to 10 mph after midnight.

Sunday: Haze in the morning. Mostly sunny with a 20 percent chance of showers. Highs around 83 near the shore to around 71 above 3000 feet. East winds around 10 mph.

South Kaua’i

Today: Sunny and haze. Highs 80 to 85. Light winds.

Tonight: Partly cloudy. Haze through the night. A 20 percent chance of showers after midnight. Lows around 64. Light winds becoming northeast around 10 mph after midnight.

Sunday: Haze in the morning. Partly sunny with a 20 percent chance of showers. Highs 80 to 85. East winds around 10 mph.

Kaua’i Mountains

Today: Sunny and haze. Highs 73 to 79 in the valleys to around 65 above 4000 feet. Light winds.

Tonight: Partly cloudy. Haze through the night. A 20 percent chance of showers after midnight. Lows 56 to 62 in the valleys to around 53 above 4000 feet. Light winds becoming east up to 15 mph after midnight.

Sunday: Mostly sunny in the morning then becoming partly sunny. Haze in the morning. A 20 percent chance of showers. Highs 72 to 78 in the valleys to around 63 above 4000 feet. East winds 10 to 15 mph.

North Kaua’i

Today: Sunny and haze. Highs 74 to 82. Light winds.

Tonight: Partly cloudy. Haze through the night. A 20 percent chance of showers after midnight. Lows 57 to 67. Light winds becoming east up to 10 mph after midnight.

Sunday: Mostly sunny in the morning then becoming partly sunny. Haze in the morning. A 20 percent chance of showers. Highs 74 to 82. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon.

East Kaua’i

Today: Sunny and haze. Highs 73 to 83. Light winds.

Tonight: Mostly clear in the evening, then mostly cloudy with a 20 percent chance of showers after midnight. Haze through the night. Lows 57 to 69. Light winds becoming northeast up to 10 mph after midnight.

Sunday: Haze in the morning. Partly sunny with a 20 percent chance of showers. Highs 72 to 83. East winds around 10 mph.

Detailed Forecast

Synopsis

An upper level ridge over the state will continue to produce dry and stable weather conditions with limited cloud cover today. Light background east to southeast winds will continue to develop this week. These light winds will continue to bring up volcanic emissions from Kilauea in the form of vog, affecting all Hawaiian Islands. Land and sea breezes will also develop over each island through most of the forecast period. A brief period of moderate easterly trade winds will blow in on Sunday, then light winds return from Monday morning onward. The pattern may shift by the end of next week with a trend towards more clouds and shower activity.

Discussion

A stable and dry weather pattern continues this morning with very stable and shallow stratocumulus clouds showing up in the regional satellite imagery. Local radar imagery also shows zero showers across the state. Upper air balloon observations in Hilo and Lihue continue to show trade wind temperature inversion heights in the 3,000 to 5,000 foot range over the past few days. This means cloud heights will be capped around the 4,000 to 6,000 foot range and any clouds that do develop will not grow deep enough for measurable shower activity. These highly stable conditions are due to strong subsidence (downward moving air) under an upper level ridge directly over the island chain. This upper ridge will linger into Wednesday of next week, where long range guidance hints at changes to the large scale weather pattern.
In addition to stable weather conditions, winds will also remain light with background east to southeast directions for most of the next seven days. Sunday will be the exception with a brief period of moderate easterly trade winds in the forecast as a surface high pressure center temporarily builds just north of the state. Light winds return from Monday morning onward. Land and sea breezes will develop over the islands each day. Southeasterly wind flow just above the surface will pull up sulfur emissions from the Kilauea Volcano, in the form of vog (Volcanic smOG) each day affecting all Hawaiian Islands for most of the next seven days. A brief decrease in vog will develop over the smaller islands from Maui to Kauai on Sunday as moderate easterly trade winds push the vog plume further westward. A slight increase in shower chances are forecast from Sunday onward.
Long range weather guidance continues to show the large scale weather pattern shifting from Wednesday onward. The upper level ridge transitions to an upper level trough as colder air moves closer to the Hawaii region with a series of cold fronts approaching the state from the northwest. This pattern shift will produce increasing clouds and showers under the influence of a more unstable upper level trough. Stay tuned.

Aviation

A strong ridge aloft will maintain dry and stable conditions with prevailing VFR today and tonight. Land and sea breezes will continue over each island for the next 12 to 18 hours, with moderate trade winds building into the state by early Sunday morning.

Marine

Surf is expected to return to High Surf Advisory (HSA) levels today and persist for most north and west facing shores through the weekend as another long period northwest swell (310 degrees) builds across the islands. Therefore, the HSA will remain in effect for most north and west facing shores through Sunday afternoon. The HSA may need to be extended if the swell lingers through Monday. Surf for east facing shores will remain small, except for some areas exposed to the declining north swell wrap today. A small south swell is expected this weekend. Current trends support surf heights remaining below HSA criteria early next week along all shores.
Surface high pressure centered northeast of the state will remain relatively stationary through the weekend, then lift northeast early next week. Light to moderate east to southeast winds will persist today, before increasing to locally breezy from the east Sunday as a ridge briefly strengthens north of the state. The ridge is expected to weaken as a front approaches the state during the first half of next week, for slightly weaker east to southeast winds.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST Sunday for north and west facing shores of Niihau, Kauai, Oahu, Molokai, and north facing shores of Maui.

Data Courtesy of NOAA.gov