Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 89 near the shore to around 77 above 3000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 69 to 74 near the shore to around 60 above 3000 feet. Northeast winds up to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly sunny with isolated showers. Highs around 89 near the shore to around 77 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

South Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs around 86. Northeast 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 67 to 73. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Wednesday: Breezy. Mostly cloudy with numerous showers in the morning, then mostly sunny with scattered showers in the afternoon. Highs around 86. Northeast winds 10 to 20 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 76 to 83 in the valleys to around 67 above 4000 feet. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 70 percent.

Tonight: Cloudy and breezy. Numerous showers in the evening, then frequent showers after midnight. Lows 60 to 65 in the valleys to around 55 above 4000 feet. East winds 10 to 20 mph decreasing to up to 15 mph after midnight. Chance of rain 80 percent.

Wednesday: Mostly cloudy. Breezy. Frequent showers in the morning, then scattered showers in the afternoon. Highs 76 to 83 in the valleys to around 67 above 4000 feet. East winds up to 15 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 80 percent.

North Kaua’i

Today: Partly sunny. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 88. East winds up to 20 mph increasing to 10 to 20 mph in the afternoon. Chance of rain 60 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 63 to 73. East winds up to 15 mph. Chance of rain 70 percent.

Wednesday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 88. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 70 percent.

East Kaua’i

Today: Mostly cloudy. Breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 87. Northeast winds 10 to 20 mph. Chance of rain 60 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then numerous showers after midnight. Lows 61 to 74. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Wednesday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 87. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Gusty easterly trade winds will linger today, then ease into the moderate to breezy range Wednesday through the weekend. As areas of moisture move through, showers will be common over windward and mauka locations, while only a few make it to the drier leeward areas.

Discussion

Guidance remains in good agreement and depicts the strong ridge north of the state that has been driving the gusty easterly trades over the past several days gradually eroding as several fronts pass quickly from west to east over the far northern Pacific. Expect the local winds to respond and begin to ease into the more typical moderate to breezy category later today through Wednesday, which should persist through the weekend. Shallow pockets of moisture moving through periodically combined with the strong trades have been producing modest rainfall each day across wetter windward areas, with some managing to make it over leeward areas from Kauai to Maui overnight through the morning periods. This trend will continue into Wednesday, as a band of moisture, currently located a couple of hundred miles to the north- northeast, approaches and clips the western end of the state later today through Wednesday. While showers will remain common for windward areas overnight through the mornings during the second half of the week, lower rainfall chances are expected for leeward areas of the smaller islands due to a combination of the stable conditions, inversion height hovering around 7000 ft, and the trades easing slightly.

Aviation

Expect breezy trade winds to continue today with a high pressure ridge anchored north of the Hawaii region. The ridge will slowly weaken starting on Wednesday with a gradual decrease in wind speeds into the second half of the week. An upper level low will produce periods of showers mainly along northeast mountain slopes of each island in the overnight to early morning hours. Brief periods of showers are possible during the day. Stronger showers may occasionally drift into leeward airfields.
AIRMET Sierra remains in effect for mountain obscuration along windward areas of the Big Island and Maui through the overnight hours. These conditions may diminish by this morning.
AIRMET Tango will remain in place for low level turbulence over and downwind of island mountains today and these conditions will likely continue into tonight.

Marine

A ridge of high pressure will remain nearly stationary north of the islands and gradually weaken over the next couple of days. The Small Craft Advisory (SCA) will be scaled down to the typically windy zones around Maui County and the Big Island this morning through the end of this week.
Another pulse of long-period, south-southeast swell will hold today, maintaining advisory level surf through this afternoon. Surf will gradually subside Wednesday through Thursday to the summer average or lower.
Surf along east facing shores will remain rough and choppy due to the fresh to locally strong trades, but gradually subside into the weekend as the trades ease. A small north-northwest swell will continue to diminish today, though some trade wind swell will still wrap into exposed north shores.

HFO Watches/Warnings/Advisories

High Surf Advisory until 6 PM HST this evening for Niihau, Kauai Leeward, Waianae Coast, Kahoolawe, Maui Leeward West, Kona, Kauai South, East Honolulu, Honolulu Metro, Ewa Plain, Molokai Southeast, Molokai Leeward South, Lanai Leeward, Lanai South, Maui Central Valley South, South Maui/Upcountry, South Haleakala, Big Island South, Big Island Southeast.
Small Craft Advisory until 6 AM HST early this morning for Oahu Leeward Waters, Kaiwi Channel, Maui County Windward Waters.
Small Craft Advisory until 6 AM HST Saturday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov