Tropical Storm Darby’s exact path toward Hawaii Island remained something of a mystery Friday afternoon, but one thing was clear: Effects from the storm were unavoidable.
Tropical Storm Darby’s exact path toward Hawaii Island remained something of a mystery Friday afternoon, but one thing was clear: Effects from the storm were unavoidable.
“Even though Darby’s essentially on the doorstep of the Big Island, there’s still some uncertainty about the eventual path it’s going to take,” National Weather Service forecaster Tom Birchard said Friday afternoon.
The NWS anticipated the storm system, which entered the Central Pacific basin earlier this week and was moving on a westward track, would take a turn to the northwest at some point.
As of 5 p.m. Friday, it had not yet turned. The NWS forecast issued at that time said the northwest turn was expected Friday night.
“It was also expected to slow down in its forward motion, and it hasn’t yet,” Birchard said.
By contrast, he said, Tropical Storm Iselle had a stable track before it made landfall on the Big Island in 2014.
Heavy rains and high winds were predicted to arrive Friday evening and continue through today. Forecasters advised residents to be prepared for all weather-related scenarios.
If the storm system did not make a northwest turn, there was a possibility its center could come ashore. There also was a possibility it could pass by to the south instead.
“There’s still that much uncertainty,” Birchard said.
Darby, he said, could be one of the uncommon cases where the storm center lies outside the NWS cone of uncertainty used on forecast maps.
At the time of the late afternoon forecast, Darby was 205 miles east-southeast of Hilo and moving at a speed of 12 mph. Tropical storm-force winds extended 125 miles from its center, and maximum sustained winds were at 60 mph.
Expected rainfall for the Big Island was somewhere between 10 and 15 inches.
“There’s going to be no avoiding the heavy rain,” Birchard said.
Tropical storms bring “a triple threat,” he said. Besides the rain, which can lead to flash flooding and ponding of water, high surf and strong winds are expected.
On Friday afternoon, surf already was being reported at 20 feet in some windward locations, Birchard said. Honolii was reporting regular 10- and 12-foot swells with occasional 18-foot peaks.
“Like we saw with Iselle, especially on the windward side, we see a similar type of wave run-up (on shore properties),” Birchard said. “The other thing that affects more places would be the strong, gusty winds.”
Gusts of up to 55 mph were expected beginning Friday evening.
Winds tend to accelerate while moving through the Hilo and Puna districts, Birchard said.
“I think there’s still plenty of albizia to be taken out,” he said.
Depending on the storm’s eventual path, wind and surf should diminish by late Sunday, Birchard said.
Residents were advised to have their storm preparations taken care of on Friday. Emergency shelters, including many pet-friendly locations, opened across the island.
As of 5 p.m. Friday, a tropical storm warning also was in effect for Maui County. A tropical storm watch also was issued for Oahu.
Gov. David Ige and Hawaii County Mayor Billy Kenoi issued emergency proclamations Friday ahead of Darby’s arrival.
Ige’s proclamation “authorizes the expenditure of state monies for quick, easy and efficient relief of disaster-related damages, losses and suffering resulting from the storm,” according to a release.
“The state is standing by to assist the counties — particularly Hawaii and Maui counties — which are expected to be the first to feel the impact of Tropical Storm Darby,” Ige said.
Email Ivy Ashe at iashe@hawaiitribune-herald.com.