Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 89 near the shore to around 77 above 3000 feet. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows around 72 near the shore to around 63 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Wednesday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 86 to 92 near the shore to around 77 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

South Kaua’i

Today: Partly sunny with scattered showers. Highs 84 to 91. Northeast winds around 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows 70 to 75. Northeast winds 15 to 20 mph. Chance of rain 70 percent.

Wednesday: Breezy. Partly sunny with scattered showers. Highs 84 to 90. East winds 15 to 20 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs 75 to 84 in the valleys to around 68 above 4000 feet. East winds around 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then occasional showers after midnight. Lows 66 to 71 in the valleys to around 60 above 4000 feet. East winds 15 to 20 mph. Chance of rain 80 percent.

Wednesday: Mostly cloudy. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs 75 to 85 in the valleys to around 68 above 4000 feet. East winds 15 to 20 mph. Chance of rain 70 percent.

North Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 78 to 89. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 67 to 74. East winds 10 to 20 mph. Chance of rain 50 percent.

Wednesday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 78 to 89. East winds 10 to 20 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 75 to 87. Northeast winds around 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows 66 to 77. East winds around 15 mph. Chance of rain 70 percent.

Wednesday: Breezy. Partly sunny with scattered showers. Highs 75 to 88. East winds 15 to 20 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Expect a trade wind weather pattern through the weekend, with clouds and showers favoring windward and mauka areas. Trade winds will remain in the moderate to locally breezy range. Total rainfall will be light as a persistent subsidence inversion caps cloud and shower development.

Discussion

There is little to no change in synoptic setup and forecast philosophy from last evening. High pressure far north of the main Hawaiian Islands continues to drive moderate to breezy trade winds across local waters this morning. Overnight soundings show that our airmass is not particularly dry or stable, but is capped at around 5000 feet by a subsidence inversion that limits cloud and shower development. Satellite loop shows a broad field of stable broken to overcast low clouds extending from Hawaiian windward waters almost all the way to the mainland. The western edge of this cloud field covers most windward shores and slopes at this hour. However, radar corroborates the effects of the capping inversion by showing very little activity beneath this cloud cover.
Models show high pressure will remain parked far north of the islands through the week, while ridging aloft caps cloud and shower development. This pattern will keep the state embedded within trade wind flow. Moderate to breezy east northeast trade winds will continue into the foreseeable future. Limited showers riding in on the trades will focus over windward shores and slopes. The leeward side of the Big Island will see a diurnal pattern of mostly clear skies in the morning and then increasing clouds and scattered showers each afternoon before clearing again overnight.

Aviation

Moderate to locally breezy trade winds will continue for the next several days. These locally breezy winds will support continuing AIRMET Tango for moderate low-level turbulence downwind of the terrain of all islands through at least mid-week.
As of 2 am Tuesday, satellite imagery showed thick bands of stratocumulus and scattered light showers hugging the northeast slopes and coasts of the Hawaiian Islands. AIRMET Sierra for mountain obscuration is currently in effect for Kauai and Oahu. Conditions may temporarily spread to the windward slopes of the other islands later this morning. Clouds are expected to lift and clear over inland areas in the afternoon.
This trade wind weather pattern with clouds and showers favoring windward locations, especially during the overnight through morning hours, will continue through the remainder of the week.

Marine

Surface high pressure centered far north northwest of the islands is producing a tight pressure gradient down across the state. This will equate to fresh to locally strong trade winds through the week. The Small Craft Advisory (SCA) for winds in effect for the typical windier waters surrounding Maui County and Big Island has been extended through early Thursday morning.
No significant swells are expected over the several days. Thus, small surf heights along all shores are forecast this week. A small, long period south swell that arrived yesterday and has produced a minor bump in south-facing surf heights that will linger through mid week. East-facing shore surf driven by trade wind wave energy will remain small and choppy for the foreseeable future.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Thursday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov