Nolo expected to reach hurricane strength near Hawaii by Friday, flooding threat grows

A tropical system southeast of Hawaii is expected to become Tropical Storm Nolo by Wednesday and a hurricane by Thursday — putting the Big Island in the path of potentially feet of rain starting as early as Wednesday evening, according to forecasters. It would be the fourth tropical system to threaten Hawaii this season.

The system, the remnants of Tropical Depression 15-E, had previously fizzled after running into strong wind shear. But it kept moving west and has now entered an environment with less shear, allowing it to reorganize. The Central Pacific Hurricane Center gives it a 60% chance of becoming a cyclone within two days and a 90% chance within the week, according to The Garden Island.

The most likely track, according to The Weather Company, keeps the storm's center south of the Big Island — slowing and meandering there starting Thursday before resuming a west-northwest track early next week. A second scenario has it tracking closer to or even making landfall on the Big Island. Tropical storm watches could be posted for parts of Hawaii later Wednesday.

Either way, the rainfall threat is severe. Hawaii News Now reports wet weather could begin for Hawaii Island as soon as late Wednesday, with up to two feet of rain or more possible by Sunday. Winds could gust to 60 or 70 mph on Big Island summits and on the upper slopes of Haleakalā on Maui. The Weather Company notes that at higher elevations, rainfall could be measured in feet rather than inches if the worst scenario plays out. A Flash Flood Watch and Wind Advisories are expected to be posted.

The concern is compounded by what the islands have already endured this season. Hurricane Lala's eyewall grazed the southern Big Island, causing torrential rain, power outages, and — according to The Garden Island — flooding that damaged hundreds of homes and killed two residents in the Kau district. Tropical Storm Moke followed, hitting the Big Island with rain and winds from its outer bands; flooding still occurred because the ground was already saturated from Lala. Then Hurricane Lowell, which reached Category 5 strength at its peak, weakened before its closest pass but still slammed the western islands with wind, rain, and waves.

The possibility of another round of heavy rainfall in areas hit hard by Hurricane Lala is a major concern. As this develops, we will continue to provide the public with updates as well as work closely with the weather service and our other partners to prepare for whatever this storm might send our way.— Kimo Alameda, Big Island Mayor

We can hope it stays weak or stays away, but we need to respect the potential power of the storm and be ready for whatever it brings.— Darryl Oliveira, Acting Civil Defense Administrator, Hawaii County

Hawaii County officials said forecast models vary greatly on potential impacts, ranging from a few inches of rain to as much as two feet with strong winds in isolated areas. They noted it is difficult to predict the storm's track precisely until it fully organizes into a cyclone.

Hawaii County's Civil Defense Administrator urged residents to make a shelter plan, trim vegetation that could be downed by wind, clear drainage areas and gutters, stock emergency food, water, and medication for all household members including pets, and prepare for potentially lengthy power outages.

Hawaii Island and Maui County are considered most likely to see the largest rain accumulations, according to Hawaii News Now. The Garden Island noted that Kauai County, still recovering from Hurricane Lowell, is also monitoring the situation.

Why it matters — Hawaii Island and Maui face potentially catastrophic flooding from a fourth tropical system this season, arriving before communities and saturated ground have fully recovered from Lala, Moke, and Lowell.

Reported by hawaiinewsnow.com, weather.com, kitv.com, thegardenisland.com