Hone — 2024

A slow-moving disturbance in the eastern Pacific organized into a tropical depression on 22 August about 1,000 nautical miles east‑southeast of the Hawaiian Islands, crossed into the Central Pacific the same day, and became Tropical Storm Hone on 22 August. Hone tracked generally west‑northwestward then westward along the southern edge of a subtropical ridge. It strengthened as it approached Hawaii, reached hurricane strength on 25 August, weakened to a tropical storm on 26 August, became a depression by 30 August well west of Kauai, briefly regained tropical storm strength on 31 August, then became a post‑tropical low and dissipated on 1 September. Hone passed just south of the Island of Hawaii (the Big Island) on 24–25 August, producing its closest approach and most impacts there. No direct landfall over a major island was recorded in the report; the center passed approximately 45 nautical miles south of South Point, Hawaii, at peak intensity on 25 August. Tropical storm warnings had been issued for the Big Island beginning 24 August and discontinued on 26 August. Maximum sustained winds peaked at 75 kt (about 86 mph surface estimate using standard reduction factors) around 1200 UTC 25 August, with a minimum central pressure near 988 mb. That peak corresponds to a Category 1 hurricane on the Saffir‑Simpson scale. Flight‑level and radar data, aircraft dropsondes, and satellite analyses supported the peak intensity estimate. Storm surge at Hilo Bay (Kuhio Bay) reached a modest 0.73 ft (0.22 m) above mean higher high water, with no reported coastal inundation. Heavy rainfall fell on the Big Island’s east and southeast slopes: 33.58 inches in Volcano Village over two days, 28.82 inches at Hakalau RAWS, 25.03 inches at Saddle Quarry, 24.46 inches at Kulani NWR, and more than 21 inches at Mountain View and Waiākea Uka. Hourly rates were generally below 1 inch per hour, but upslope totals produced flash flooding and road closures. There were no confirmed fatalities or serious injuries. Widespread downed trees and power lines occurred, and over 24,000 customers experienced power outages statewide, with the Big Island hardest hit. At least 38 damage claims were submitted for structures on the windward side of the Big Island; nine surveyed structures had major damage and one home (the former “Hobbit House” in Waiohinu) suffered extensive flood damage. Maui and Oahu experienced impacts from strong gradient winds as well. Forecasting and warnings performed well: the system’s development was anticipated in Tropical Weather Outlooks up to 7 days in advance, and official track and intensity forecasts generally outperformed many guidance models. Official intensity forecasts had lower errors than recent five‑year means at all forecast intervals; track forecast errors were lower than the five‑year mean at 12, 24, and 120 hours but higher at some other intervals.