Unala — 2013

Tropical Storm Unala formed very quickly in the central North Pacific near the International Date Line. It developed from a broad area of disturbed weather and is estimated to have become a tropical storm at 0000 UTC on 19 August 2013, about 325 nautical miles northeast of Tropical Cyclone Pewa. Unala was short-lived: it weakened to a tropical depression by 0600 UTC the same day and dissipated before 1200 UTC on 19 August after being absorbed by the circulation around Pewa. Unala did not make any landfalls. It remained over open ocean throughout its life and was absorbed by the nearby circulation of Tropical Cyclone Pewa while still well east of the International Date Line. The storm’s peak intensity was 35 knots (40 mph) with a minimum central pressure of 1005 mb, corresponding to a minimal tropical storm. The best-track placed that peak at 0000 UTC on 19 August 2013. Because Unala stayed far from land, there were no reports of storm surge or measured rainfall impacts on named cities or counties. No ships or coastal stations reported tropical-storm-force winds associated with Unala. There were no reported deaths, injuries, or damage attributable to Unala. The system was notable mainly for its very short lifespan and close proximity to two other circulations (Pewa and the disturbance that became Tropical Depression Three‑C), which contributed to its rapid weakening and absorption. Forecasters had difficulty predicting Unala’s development despite tracking the parent disturbance for several days; genesis was poorly forecast and no watches or warnings were issued.