Rain has been the big story associated with now-Tropical Storm Lane in the central Pacific Ocean. Since midweek, some of the Hawaiian islands have been experiencing rain from this slow-moving, moisture-rich system, and the rains will continue across many of the islands this weekend.
The Big Island has been affected particularly hard so far. More than 2 feet of rain has been measured in a 36-hour time period by Friday night on the windward side of the islands. “Catastrophic flooding” has been reported, according to the National Weather Service at Honolulu.The 45.8 inches Waiakea Uka has gotten has singlehandedly made Lane the 4th rainiest US tropical cyclone.
A lack of steering winds has allowed for two things: to move the storm to the north and to move at a very slow pace. This Saturday, however, we’ll begin to see Lane take another turn to the west, traveling parallel to the northern Hawaiian islands. Thankfully, the storm will not make landfall and the increased wind shear as of late has allowed for Lane to weaken into a tropical storm. By Sunday, Lane will depart from the Hawaiian islands, allowing for conditions to improve. Lane will also weaken further into a tropical depression by next week.
According to the National Hurricane Center, “Tropical storm conditions are still expected in and near outer rain bands that will affect Oahu, Maui County and the Big Island today. Tropical storm conditions are possible on Kauai starting later today.” Tropical Storm Watches and Warnings remain in effect for all of the islands as a result of the possible tropical-storm-force winds (39 mph or greater).
What we’re more concerned about is the heavy rain. During the morning hours on Saturday, there will be clusters of heavy showers affecting some of the islands, while a more pronounced band of rain will be located to the south. This band will have to be watched very closely to see how far north it progresses. If it moves far enough to the north to affect islands like Maui, then that will definitely ramp up the flash flood risk.
The risk for additional heavy rain will then wind down beginning on Sunday, although lingering rain showers and gusty winds will remain possible. Localized areas may receive an additional 6+ inches of rainfall. Waves will also still be elevated through early next week as Lane gradually weakens and departs from Hawaii.