Powerful kona storm brings warning level winds and flash flood risks

A powerful kona storm is producing periods of hazardous weather impacts across the Hawaiian Islands through the weekend. Threats range from significant flash flooding, damaging winds, strong to severe thunderstorms, and snow and ice over the highest Big Island summits.

The National Weather Service reports southerly to southwesterly winds will be strongest from today to tomorrow and will produce damaging wind gusts. “The highest threats for damaging winds remain along north and east of the island mountains. Unsettled wet weather conditions with decreasing southwesterly wind trends will continue into early next week,” the NWS reports.

This kona storm begins to lift northward on Monday, and unsettled weather will start to ease across the state. High pressure will build back in north of the state on Wednesday allowing trade winds to return spreading from north to south down the island chain reaching Maui and the Big Island by Thursday morning.

A High Wind Warning is in effect for Maui County through 6 a.m. on Sunday. South to southwest winds 30 to 40 mph with gusts up to 70 mph are expected. Island wide strong gusty winds are possible, but areas most at risk are communities north and east of steep mountains.

A Flood Watch is now in effect for Maui County through Sunday night. Considerable flash flooding is possible as a large and powerful kona storm northwest of the state draws deep tropical moisture across the islands. Persistent bands of heavy rain and thunderstorms may produce intense rainfall rates, leading to rapid rises in streams and flooding of roads and low-lying areas.

A Flood Advisory has been extended until 1 p.m. for the island of Maui. At 9:50 a.m., radar showed areas of heavy rain continuing to move over Maui from the southwest, falling at a rate of 1 to 2 inches per hour. Rainfall is heaviest along the south and southeast facing areas of the island, including Piʻilani Highway on south slopes of Haleakalā. Additional areas of heavy rain are expected over the next few hours.

A Flood Advisory is now in effect until 11:15 a.m. for the island of Molokaʻi in Maui County. At 9:35 a.m., radar showed heavy rain continuing to move over the island, falling at a rate of 1 to 2 inches per hour. Water levels in Kawela Gulch stream were rising rapidly, though no significant impacts have yet been reported. Rainfall is expected to ease over the next hour, but lingering flood impacts are still possible.