Photo Credit: Jason Weingardt

West Kaua’i

Today: Mostly sunny with isolated showers. Highs around 91 near the shore to around 79 above 3000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Lows around 73 near the shore to around 62 above 3000 feet. Northeast winds up to 15 mph.

Wednesday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs around 91 near the shore to around 78 above 3000 feet. East winds up to 15 mph. Chance of rain 50 percent.

South Kaua’i

Today: Breezy. Partly sunny with scattered showers. Highs 81 to 90. East winds 10 to 20 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy with isolated showers. Lows around 73. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Wednesday: Mostly cloudy with scattered showers. Highs 82 to 90. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kaua’i Mountains

Today: Mostly cloudy with scattered showers. Highs 75 to 88 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 64 to 72 in the valleys to around 59 above 4000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Wednesday: Mostly cloudy with showers likely. Highs 75 to 88 in the valleys to around 67 above 4000 feet. East winds up to 15 mph. Chance of rain 70 percent.

North Kaua’i

Today: Partly sunny with scattered showers. Highs 77 to 92. East winds up to 15 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 66 to 74. East winds up to 10 mph. Chance of rain 50 percent.

Wednesday: Partly sunny with scattered showers. Highs 77 to 91. East winds up to 15 mph. Chance of rain 50 percent.

East Kaua’i

Today: Mostly cloudy with scattered showers. Highs 74 to 87. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 65 to 77. Northeast winds 10 to 15 mph decreasing to up to 10 mph after midnight. Chance of rain 50 percent.

Wednesday: Mostly cloudy with scattered showers. Highs 75 to 87. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Detailed Forecast

Synopsis

Tropical Storm Hone continues to move westward away from the Hawaiian Islands. High pressure far north of the state will maintain a typical moderate to breezy trade wind pattern through much of the week. Tropical Cyclone Gilma far east of the state will weaken as it approaches later this week and bring the potential for more rain.

Discussion

Satellite imagery continues to show Tropical Storm Hone moving westward away from the Hawaiian Islands this morning, with high pressure re-establishing itself as the dominate feature far north of the state. This will bring the return of moderate to breezy trade winds with isolated to scattered showers over windward and mauka areas.
Dry air will continue to filter across the state today as the moisture field associated with Hone departs to the west. This swath of drier air will be short-lived as CIMSS MIMIC precipitable water imagery continues to show a broad moisture plume extending well out ahead of Tropical Cyclone Gilma. This moisture plume is expected to move into the area late tonight. This will bring an uptick in windward and mauka showers through the end of the week.
The latest forecast from the National Hurricane Center shows that Gilma has moved into the Central Pacific Basin this morning. The Central Pacific Hurricane Center will assume responsibility of Gilma later today. The current forecast shows Gilma passing near the islands sometime on Friday as a Post-Tropical/Remnant Low. This will bring another break in the trade wind pattern. Local impacts will depend on the track of this weakening system. Consensus continues to show developing troughing northwest of the region will cause Gilma to slowly recurve upon approach to the islands, potentially leading to a period of warmer weather featuring higher humidity and light southeast winds. A more southerly track would bring a greater probability of wet trade wind weather. The Central Pacific Hurricane Center will continue to monitor the progress of Gilma as it inches closer to the state.
The remnants of Tropical Cyclone Hector will follow closely behind Gilma as potentially a weak surface trough with a diffuse moisture plume sometime Saturday night into Sunday. Little to no impacts are expected from Hector at this time.

Aviation

Tropical Storm Hone will continue to drift slowly west today, away from the islands. In its wake, expect a return to typical summertime trade wind weather with scattered showers possible along windward portions of the islands. Brief MVFR conditions may accompany some of the showers, but not expecting anything widespread. Shower coverage looks increase again tonight, but again, mainly for windward areas.
There are currently no AIRMETs in effect.

Marine

Fresh to strong easterly trades will continue today as Tropical Storm Hone tracks westward and away from the Hawaiian waters. The pressure gradient will gradually weaken over the region through the week as Hone continues westward and Hurricane Gilma approaches from the east. A Small Craft Advisory is now in place for the windier waters and channels around Maui County and the Big Island through this afternoon. Winds should ease into the moderate to fresh category tonight through midweek, likely allowing the advisory to be lowered.
Although the current forecast by the National Hurricane Center shows Gilma quickly weakening as it approaches and passing the islands to the north later this week through the weekend, any deviation in the forecast track could have a more significant impact on the Hawaiian nearshore waters this weekend. The current forecast has Gilma passing north of the state Friday into the weekend as a remnant low. If that scenario is realized, the local winds could become light and variable. Refer to the latest advisories issued by the National Hurricane Center for more information on Gilma.
Surf along east facing shores will quickly ease through midweek as the easterly winds trend down. An upward trend is possible later in the week, as a medium-period easterly swell from Gilma begins to fill in.
Surf along south facing shores will hold into midweek due to a combination of a small south swell and some residual short- to medium-period south-southeast swell generated by Hone. A downward trend back to the summertime average is expected through the second half of the week.
Surf along north and west facing shores will remain near the seasonal average this week, but could slightly rise this weekend for north facing shores as Gilma approaches the region and a small northwest swell fills in.

HFO Watches/Warnings/Advisories

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

Data Courtesy of NOAA.gov