Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 84 near the shore to around 72 above 3000 feet. Light winds becoming southwest around 10 mph in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 69 near the shore to around 58 above 3000 feet. Northeast winds around 10 mph in the evening becoming light. Chance of rain 20 percent.

Saturday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 85 near the shore to around 72 above 3000 feet. Northeast winds around 10 mph shifting to the southwest up to 10 mph in the afternoon. Chance of rain 40 percent.

South Kaua’i

Today: Partly sunny. Showers likely in the morning, then isolated showers in the afternoon. Highs around 81. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 65 to 70. Northeast winds 10 to 15 mph. Chance of rain 40 percent.

Saturday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 80 to 85. East winds around 10 mph. Chance of rain 40 percent.

Kaua’i Mountains

Today: Partly sunny. Showers likely in the morning, then scattered showers in the afternoon. Highs 71 to 78 in the valleys to around 62 above 4000 feet. Northeast winds around 10 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows 58 to 63 in the valleys to around 51 above 4000 feet. Northeast winds around 10 mph. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 71 to 78 in the valleys to around 62 above 4000 feet. Northeast winds around 10 mph. Chance of rain 50 percent.

North Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 74 to 84. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 61 to 69. East winds around 10 mph. Chance of rain 40 percent.

Saturday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 74 to 84. Northeast winds around 10 mph. Chance of rain 40 percent.

East Kaua’i

Today: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 74 to 84. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 58 to 71. Northeast winds around 10 mph. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs 74 to 83. Northeast winds around 10 mph. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Light to moderate trade winds will become quite light over the weekend and early next week, with a mostly dry pattern developing. The light trade winds will deliver limited clouds and showers to windward areas, mainly during nights and mornings. Sea breezes will promote afternoon cloud development over leeward areas, also delivering just a few showers. Periods of high clouds will continue on and off through the weekend.

Discussion

Mid- and high-level clouds of varying thicknessES are over the islands this morning, moving rapidly ENE within the subtropical jet. The jet lies on the S side of an ENE-WSW oriented nearly stationary trough aloft that has an axis just N of the islands along ~25N. A low within the trough brought strong winds to the summits of Mauna Kea and Mauna Loa yesterday, but winds have diminished below Wind Advisory speeds. This trough continues to destabilize the island atmosphere, with morning soundings showing a somewhat moist and unstable profile. Light to moderate trade winds at the surface are being supported by a weakening ridge well N of the islands, with clusters of showery low clouds randomly embedded. Radar shows scattered to numerous showers around Kauai and Oahu (where showers have been most active overnight), with some small heavy cores noted. Fewer showers are noted over Maui County and the Big Island. Satellite shows very little in the way of low clouds immediately upstream of the islands.
Although showers have been fairly active in portions of the state the last couple of days, a drier air mass will bring lower PWAT values from later today into the weekend. Meanwhile, a pair of low pressure systems passing N of the islands over the next several days will weaken the trade-wind-supporting ridge, while also pushing it closer to the islands. Trade winds will weaken in response, becoming quite light on Sunday and Monday.
With the light trades and drier air mass, windward areas will see limited showers after this morning, mainly during nights and mornings. Nighttime land breezes over leeward areas will lead to mostly clear nights and mornings, giving way to onshore-flowing sea breezes in the afternoons that will fuel clouds and a few showers that will linger until sunset. Models have been trending toward a lighter wind solution for early next week, with the return of breezy trades likely delayed until midweek.
The semi-permanent trough aloft is not expected to move much over the next several days, but an embedded low will move E away from the islands today, leading to some short term stabilization of the island atmosphere. Additionally, high clouds are expected to remain fairly this over most of the state today. A new low will move the trough tonight and Saturday, potentially bringing another bout of high clouds and increased instability, although diminished PWAT and winds may prevent an increase in showers. Another shortwave moving through the trough is expected on Monday, likely with similar effects.

Aviation

A typical June tradewind pattern will persist through the forecast period thanks to a surface high far northeast of the state. Moderate trades, along with slightly enhanced low level moisture, will bring scattered to numerous showers to windward locations through this morning. Brief periods of MVFR ceilings and visibility may accompany this activity. A drier airmass will advect into the region by this afternoon and lead to decreasing shower coverage.
AIRMET Sierra remains in effect for north through east section of Oahu and Kauai for tempo mountain obscuration. AIRMET Tango remains in effect for tempo moderate upper level turbulence statewide.

Marine

Moderate to fresh trades will hold in place today, then gradually ease into the light to moderate range this weekend as the ridge north of the state weakens. The trades will strengthen back into the moderate to fresh range early next week as the ridge lifts back northward.
North shore surf will remain flat through early next week with only background northwest swell energy moving through. A new northwest swell is expected to build Wednesday, peak at moderate levels Thursday, then begin a slow decline Friday. This will give a nice, sizable, out-of-season boost to north and west shore surf late next week.
Surf along south facing shores will remain relatively steady below the seasonal average through the weekend. A slightly larger south swell is expected to arrive Sunday night, boosting south shore surf up close to seasonal levels Monday through Wednesday, with mainly background south swell energy then expected for the end of next week.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov