Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny with isolated showers. Highs around 86 near the shore to around 76 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 70 to 75 near the shore to around 61 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Monday: Mostly sunny with isolated showers. Highs around 86 near the shore to around 76 above 3000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 84. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 70 to 76. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Monday: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 84. East winds 10 to 15 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 75 to 80 in the valleys to around 67 above 4000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows around 65 in the valleys to around 57 above 4000 feet. East winds 10 to 15 mph. Chance of rain 70 percent.

Monday: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 75 to 80 in the valleys to around 67 above 4000 feet. East winds 10 to 20 mph. Chance of rain 70 percent.

North Kaua’i

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 75 to 85. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 65 to 73. East winds around 10 mph. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs 75 to 85. East winds 10 to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs 76 to 85. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 75. East winds 10 to 15 mph. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs 76 to 85. East winds 10 to 15 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

High pressure far northeast of the state will drive moderate to breezy trade winds across local waters through the forecast period, keeping a trade wind weather pattern intact. Expect clouds and showers to favor windward and mountain areas, especially at night and during the early morning hours. An upper trough forecast to move in from the northwest could enhance showers late next week.

Discussion

Trade wind flow persists across the main Hawaiian Islands this morning, thanks to high pressure far to the northeast filling in with the departure of troughing west of 160W. Our airmass has dried out and stabilized as ridging builds aloft. Overnight soundings show the trend, with Hilo's 1.19 inch PW contrasting slightly with Lihue's 1.33 inch PW. Both soundings show development of strong subsidence inversions. Radar shows isolated to scattered showers beginning to fill in across windward waters, poised to move across windward sections of the islands. Satellite loop shows patchy broken low clouds just east of the islands.
Expect moderate to breezy trades through the week. Shower coverage should remain limited today through Wednesday as ridging caps available moisture and vertical cloud development. Clouds and showers will favor windward and mauka areas, with the highest likelihood for showers occurring during overnight and early morning hours. While models show a trade wind weather pattern continuing through the forecast period, an upper trough forecast to pass across the islands from the northwest may enhance trade showers Thursday into Saturday.

Aviation

High pressure building far northeast of the state will bring moderate easterly trades to the region through the remainder of this weekend. Thus, expect scattered showers to mainly affect windward areas with mainly dry conditions elsewhere. Brief MVFR conditions may occur with this activity, though not expecting anything widespread.
No AIRMETs are currently in effect.

Marine

A strong high pressure system far northeast of the Hawaiian Islands will produce moderate to breezy trade winds today. A low pressure system far northwest of the state will slowly drift north away from the region over the next few days as another strong high pressure ridge passes from west to east across the northern Central Pacific basin. The Small Craft Advisory (SCA) was extended through Monday afternoon for the typical windier waters near Maui County and the Big Island. This SCA will likely continue into next weekend, and some expansion in areal coverage is possible, as another high pressure system passing far north of the state drifts eastward.
A small north to northwest swell will slowly decline today. A series of small background north to northwest swells are expected through the next seven days keeping north shore surf heights in the small to fun size range. Surf heights will also slowly decline along west facing shores as south swell declines and northwest swell energy shifts back to the north by the end of next week.
Small long-period south swell energy will decline today. Expect a series of background small south swells through the week, keeping small to fun sized surf along south facing shores lasting into next weekend. The return of breezy trade winds will produce small and choppy surf along east facing shores through next weekend.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov