Niala — 2015

A tropical disturbance south of the Main Hawaiian Islands gradually organized into Tropical Depression Six‑C on 0000 UTC 25 September 2015 and was named Tropical Storm Niala later that morning. Niala tracked generally northwestward then westward and slowed on 26 September, reached peak intensity that day, and turned southwest as wind shear increased. The system weakened to a tropical depression by 1200 UTC 28 September, became a remnant low at 0000 UTC 29 September, and dissipated on 1 October. Niala did not make any landfalls. A tropical storm watch was issued for the Island of Hawai‘i (the Big Island) at 2100 UTC 25 September because of its approach, but the watch was discontinued at 1500 UTC 27 September after the storm tracked well south of the island and weakened. The maximum sustained winds were 55 kt (about 63 mph) with a minimum central pressure of 992 mb at 1800 UTC 26 September, making Niala a moderate tropical storm at its peak. There were no observations of tropical‑storm‑force winds at land stations. Measured storm surge impacts were not reported in the record, and no significant surge heights are listed. Rainfall and streamflow observations associated with Niala are not detailed in the report and no specific rainfall totals for cities or counties were provided. There were no reports of damage or casualties—no deaths or injuries were attributed to Niala. The greatest impacts were avoided because Niala remained south of the Hawaiian Islands and weakened before approaching land. Noteworthy items: the storm formed from a disturbance first mentioned in forecasts on 20 September, and its genesis was reasonably well predicted. Forecast track and intensity errors by the Central Pacific Hurricane Center were generally lower than or comparable to recent averages for several forecast intervals.