Photo Credit: Brendan Stephen

West Kaua’i

Today: Partly sunny. Scattered showers early in the morning. Isolated showers late in the morning, then scattered showers in the afternoon. Highs 89 to 94 near the shore to around 79 above 3000 feet. Northeast winds up to 10 mph in the morning becoming light. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 75 near the shore to around 65 above 3000 feet. Light winds. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers. Highs around 90 near the shore to around 78 above 3000 feet. South winds around 10 mph. Chance of rain 50 percent.

South Kaua’i

Today: Mostly cloudy. Scattered showers early in the morning. Isolated showers late in the morning, then scattered showers in the afternoon. Highs 84 to 91. Northeast winds around 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 75. Light winds. Chance of rain 50 percent.

Saturday: Mostly cloudy with scattered showers. Highs 82 to 90. Light winds becoming south around 10 mph in the afternoon. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy. Scattered showers in the morning, then numerous showers in the afternoon. Highs 75 to 88 in the valleys to around 69 above 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows 67 to 74 in the valleys to around 62 above 4000 feet. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 70 percent.

Saturday: Mostly cloudy with numerous showers. Highs 77 to 88 in the valleys to around 68 above 4000 feet. South winds up to 10 mph in the morning becoming light. Chance of rain 70 percent.

North Kaua’i

Today: Mostly cloudy. Scattered showers until late afternoon, then numerous showers late in the afternoon. Highs 78 to 92. Northeast winds around 10 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy with numerous showers. Lows 69 to 76. Northeast winds up to 10 mph in the evening becoming light. Chance of rain 70 percent.

Saturday: Mostly cloudy with numerous showers. Highs 78 to 92. Light winds. Chance of rain 70 percent.

East Kaua’i

Today: Mostly cloudy. Scattered showers until late afternoon, then numerous showers late in the afternoon. Highs 76 to 88. Northeast winds around 10 mph. Chance of rain 70 percent.

Tonight: Cloudy with numerous showers. Lows 68 to 78. North winds up to 10 mph in the evening becoming light. Chance of rain 70 percent.

Saturday: Mostly cloudy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 76 to 89. South winds around 10 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

A wet weather pattern remains in the short range forecast as unstable tropical moisture associated with the remnants Gilma pass just north of the island chain. This will be more of a beneficial rain event for Hawaii and not a wind threat as the best dynamics for wind and weather will remain on the north and east sides of the remnant low center. Additional wet weather will move westward into the islands from Saturday night into Sunday as a weak disturbance associated with the remnants of Hector move through the state. The East Pacific high will drift south and strengthen early next week, increasing stability across the region and keep trade winds blowing from moderate to breezy levels.

Discussion

The satellite picture this morning shows convective showers and thunderstorms developing within a band on the northeast side of the post-tropical remnants of Gilma. Isolated thunderstorms are developing this morning along the southern flank of the surface low center just north of the Big Island. Some of these developing thunderstorms may drift into Maui and Molokai later today as the low center drifts westward. Bands of clouds on the south side of the low will drift into the islands later today spreading periods of clouds and showers from east to west across the state through tonight. Farther to the east a weak disturbance associated with the remnants of Hector are approaching the islands with yet another round of enhanced showers spreading westward across the state from Saturday night into Sunday. Isolated thunderstorms are possible along the northern slopes of Molokai, Maui and the Big Island today.
The wind forecast keeps a hybrid light to moderate trade wind and sea breeze pattern through Sunday. These weaker large scale winds are due to the low center of the Gilma remnants passing north of the state, which weakens the local area pressure gradient and the wind speeds. Afternoon sea breezes will tend to build clouds over island mountain and interior sections. Brief showers are possible in this pattern even over areas leeward of island mountains as the background lighter trade winds converge with the onshore sea breeze winds.
Trade winds will then strengthen into the moderate to breezy range by Sunday night, after the remnants of Hector pass through the island chain, and the high pressure ridge builds back over the region. More stable conditions will build into the Hawaii region next week as the Gilma and Hector remnants move out and the high pressure system far northeast of the state builds back in. Brief passing showers will linger mainly over windward and mountain areas next week, and these showers will favor the typical overnight to early morning hours.

Aviation

Trades will be weaker across the island chain as remnants of Gilma pass northwestward along the islands. Deeper moisture levels will enhance SHRA over windward and mauka areas through the rest of today. MVFR conds are possible in SHRA but VFR should generally prevail.
AIRMET Sierra for mtn obsc is in effect for windward portions of all islands as low cigs and SHRA fill in. This will likely be needed for most of today due to the remnants of Gilma.

Marine

Remnants of Gilma, just outside the coastal waters about 60 miles northeast of Hilo is forecasted to pass just north of the islands through tonight. A small area of fresh to strong easterly winds will persist along the northern portion of the circulation of Gilma and affect outer areas of windward waters. Elsewhere, trade winds will decline to gentle to moderate strength and turn northerly ahead of Gilma, then switch out of the southeast to south after the circulation passes by. Heavy showers and isolated thunderstorms may develop near Gilma as it moves through. Southeasterly winds will slowly build and become more easterly on Saturday, followed by moderate to locally strong easterly trade winds Sunday through Tuesday. Trades may diminish during the middle of next week.
Surf along east facing shores of Oahu and Kauai could remain slightly elevated for Oahu and Kauai today as short to medium period swell from Gilma moves through. For the rest of the islands, surf along east facing shores will continue to diminish today. Returning trade winds will produce moderate east shore surf Sunday into early next week.
Generally small surf will prevail on other shores. Tiny to small background swells from the south and southeast will keep the surf from going entirely flat for south facing shores. A small northwest swell is expected to slowly fill in today, then diminish during the weekend.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov