Conditions will deteriorate across Hawaii this weekend as Darby delivers locally heavy rain and rough surf. But the tropical storm will provide long-term benefits.
Darby will remain a tropical storm as it tracks onto Hawaii's Big Island later on Saturday and then near or in between Oahu and Kauai to end the weekend.
Rain and gusty winds will increase from east to west across the island chain through the weekend. Since Darby will slowly weaken as it crosses the area, the Big Island will face the most adverse impacts.
"The main impact from Darby will be in the form of significant rainfall," AccuWeather Meteorologist Evan Duffey said.
"The eastern half of the Big Island should see the most rainfall, with 2-4 inches along the coast and perhaps high amounts on the eastern flank of the island's volcanoes," he said.
Rain amounts are likely to exceed 8 inches on the eastern slopes of the higher terrain.
"Given the amount of rainfall expected, there is concern for some flash flooding and possibly a few landslides," Duffey said.
Rainfall will generally be on the order of 2-4 inches across the rest of the islands with more localized flash flooding.
Wind gusts of 40-50 mph will also be common throughout Hawaii with locally higher gusts expected on the Big Island, especially in the higher terrain. Sporadic power outages, tree damage and damage to some structures could occur.
"Area residents would be wise to secure their property as much as possible, especially outdoor items like lawn furniture," Duffey said.
Dangerously rough seas, occurring well ahead of Darby's rain and wind, will continue to pound the islands and threaten boaters, swimmers and surfers through the weekend.
The east-facing beaches will face the highest surf and greatest risk for dangerous rip currents. The pounding surf may also lead to coastal flooding, especially along the Big Island's eastern coast.
Despite the hazards and disruptions to weekend plans and vacations, Darby may be beneficial in one way.
"Much of Hawaii, especially away from the windward sides of the islands, is experiencing a drought," Duffy said. "The rainfall from Darby should put a dent in those conditions."
The majority of the abnormally dry and drought conditions are at the leeward locations, according to the U.S. Drought Monitor. However, Hilo has only received 60 percent of its normal rainfall so far this year.
As Darby departs, locally drenching showers will persist across Kauai on Monday as the rest of the islands are humid with spotty afternoon sea-breeze showers. A more typical trade wind shower pattern will resume by midweek.