Photo Credit: Brendan Stephen

West Kaua’i

Today: Partly sunny. Breezy. Isolated showers in the morning. Highs around 90 near the shore to around 78 above 3000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy. Lows around 72 near the shore to around 62 above 3000 feet. East winds 10 to 15 mph.

Friday: Partly sunny. Breezy. Highs around 90 near the shore to around 77 above 3000 feet. East winds 15 to 20 mph.

South Kaua’i

Today: Breezy. Partly sunny with isolated showers. Highs 82 to 89. East winds 15 to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows around 74. Northeast winds 15 to 20 mph. Chance of rain 20 percent.

Friday: Breezy. Partly sunny with isolated showers. Highs 81 to 89. Northeast winds 20 to 25 mph. Chance of rain 20 percent.

Kaua’i Mountains

Today: Breezy. Partly sunny with isolated showers. Highs 74 to 86 in the valleys to around 66 above 4000 feet. East winds 10 to 25 mph. Gusts up to 45 mph in the morning. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 64 to 71 in the valleys to around 59 above 4000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Friday: Breezy. Partly sunny with isolated showers. Highs 74 to 85 in the valleys to around 66 above 4000 feet. East winds 15 to 20 mph. Chance of rain 20 percent.

North Kaua’i

Today: Breezy. Partly sunny with isolated showers. Highs 77 to 91. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 66 to 74. East winds 10 to 20 mph. Chance of rain 20 percent.

Friday: Breezy. Partly sunny with isolated showers. Highs 76 to 90. East winds 15 to 20 mph. Chance of rain 20 percent.

East Kaua’i

Today: Breezy. Partly sunny with isolated showers. Highs 74 to 86. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 66 to 76. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Friday: Breezy. Partly sunny with isolated showers. Highs 74 to 86. Northeast winds 15 to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Expect gusty trade winds through early Friday as dry and stable air settles over the region. Trades will gradually decrease over the weekend into next week as relatively dry conditions continue.

Discussion

Our airmass continues to slowly dry and stabilize this morning. Shower activity decreased noticeably since yesterday afternoon and rainfall amounts were small overnight compared to the past several days. Satellite loop shows patchy broken high clouds somewhat obscuring the view of lower clouds. However, only sparse windward low cloud cover is noted through the high cloud cover gaps. Relative humidity is trending lower and trade winds remain breezy in many locations. Overnight soundings show an inversion strengthening near 4500 feet. This inversion, while somewhat elevated yesterday afternoon, is expected to lower over the next 24 to 48 hours as upper ridging builds in.
Expect gusty winds for the next few days due to the lowering inversion and a steepened pressure gradient. Models show the areas normally prone to accelerated trades, such as South Point and Leeward Kohala on the Big Island and leeward West Maui, may expect strong wind gusts near wind advisory threshold. This condition will need to be closely monitored over the next day or two. Trade winds look to ease to breezy levels this weekend and hold, along with relatively dry conditions, through early next week.

Aviation

Breezy to strong trades should persist over the next few days. SHRA and low cigs will favor windward and mauka locations. SCT SHRA look to also build up on the Kona slopes of the Big Island during the afternoon hours. MVFR conds will be possible within SHRA but VFR should prevail.
AIRMET Sierra is not in effect but with lowering cigs and SHRA it may be needed tonight for windward locations.
AIRMET Tango for mod low level turb is in effect for areas downwind of island terrain and will likely be needed for the next couple of days due to the strong trades.

Marine

Surface high pressure far northeast of the waters will continue to produce strong to locally near gale trade winds through Friday. A Small Craft Advisory (SCA) has been extended for all Hawaiian waters through Friday. As the high weakens this weekend, trade winds should ease back to fresh to locally strong speeds. The SCA may need to be trimmed by the weekend to just the typical windier areas around Maui County and the Big Island.
Rough and choppy surf will continue over the next few days along east facing shores before gradually easing early next week. Local wind swell may wrap into select north and south facing shores. All other shores look to remain nearly flat today before a background south swell could produce some small surf along south facing shores on Friday. Otherwise, no significant swells are expected for the rest of the week.

Fire weather

Gusty trade winds tonight through Friday could present some fire weather concerns in the normally windier trade wind areas and downslope leeward locations such as West Maui and leeward Kohala on the Big Island. The strongest wind gusts are more likely on Thursday and Friday as the inversion strengthens. Trade winds will gradually decrease this weekend into early next week, but dry leeward conditions will likely persist. Humidity will generally trend downward over the next few days, especially across leeward areas, adding to the fire weather concerns in those areas with gusty winds.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Friday for all Hawaiian waters,

Data Courtesy of NOAA.gov