Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny in the morning then becoming partly sunny. Isolated showers. Highs around 89 near the shore to around 77 above 3000 feet. Northeast winds up to 10 mph shifting to the west in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy. Isolated showers in the evening, then scattered showers after midnight. Lows 70 to 75 near the shore to around 61 above 3000 feet. Northeast winds up to 10 mph. Chance of rain 50 percent.

Saturday: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs around 89 near the shore to around 77 above 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

South Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs around 86. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 68 to 74. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 85 to 90. Northeast winds 10 to 15 mph. Chance of rain 60 percent.

Kaua’i Mountains

Today: Partly sunny with scattered showers. Highs 76 to 83 in the valleys to around 67 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 61 to 66 in the valleys to around 56 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Saturday: Mostly cloudy. Numerous 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 15 mph in the afternoon. Chance of rain 60 percent.

North Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 79 to 88. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 64 to 74. East winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers. Highs 79 to 88. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Partly sunny with scattered showers. Highs 79 to 87. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 62 to 75. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Saturday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 79 to 88. Northeast winds 10 to 15 mph. Chance of rain 60 percent.

Detailed Forecast

Synopsis

Expect trade winds to continue in the moderate range as the high pressure ridge far north of the region weakens through the weekend. An easterly wave will drift into the Hawaiian Islands from the east this weekend, boosting cloud and shower activity mainly in the overnight to early morning hours. High pressure builds back in from the north on Monday decreasing shower activity and producing locally breezy trade winds through Wednesday.

Discussion

The large scale weather pattern continues to show a weak high pressure ridge far north of the Hawaiian Islands producing moderate trade winds. A narrow upper level trough remains locked in place over the Hawaii region with a few embedded unstable lows. A band of cirrus clouds drifting up from the south, outlines the subtropical jet stream and an upper level ridge over the islands. Satellite imagery shows cooler/higher cumulus cloud tops moving into the windward slopes of Maui County and Oahu this morning. Expect periods of showers mainly over north through east sections of these islands at least through the morning hours.
Typical trade wind weather for this time of year will continue through Friday night with brief passing showers possible mainly over windward slopes of each island favoring the overnight to early morning hours. A subtle change will develop this weekend as another weak easterly wave, currently near 148W longitude, will drift westward over the island chain by Saturday and lift cloud heights to produce a slight boost in shower activity into Sunday.
By Monday the weather pattern changes yet again, as the easterly wave passes west of the state and high pressure builds in from the north. Expect trade wind speeds to increase into the moderate to breezy range with more stable conditions aloft decreasing shower activity. Drier and breezy weather should last from Monday through at least Wednesday.

Aviation

Surface high pressure north of the state will continue to help generate moderate to locally breezy trades across the islands through the forecast period. Thus, scattered showers will mainly focus along the windward slopes. Some of the more robust activity may produce brief periods of MVFR ceilings and visibility. Isolated showers expected elsewhere.
AIRMET SIERRA remains in effect for north through east sections of Kauai for mountain obscuration above 2500 ft due to clouds and showers.
AIRMET TANGO remains in effect below 9000 feet over and immediately south through west of mountains due to tempo moderate turbulence.

Marine

A ridge of high pressure north of the state has weakened slightly overnight, dropping winds below Small Craft Advisory levels across the adjacent coastal waters. As a result, the SCA has been cancelled with the morning forecast package.
Not much change in the overall trade wind strength is during the next couple days, with the driving ridge remaining anchored to the north of the state and keeping trades in the moderate to fresh range. The ridge is expected to strengthen Sunday, boosting the trades into the moderate to locally strong range, with further strengthening bringing fresh to strong trades to the waters Tuesday through late next week.
Surf along south facing shores will remain small and below the summertime average through next Friday with mainly background southerly swells moving through.
Surf along north facing shores will remain small and near typical summertime levels through next Friday.
East shore surf will remain small through Monday, then gradually trend upward and close to seasonal levels Tuesday through next Friday.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov