Irwin — 2023

Tropical Storm Irwin formed from a tropical wave that moved westward from Central America and became a distinct system in the eastern North Pacific on 26 August 2023. It was short-lived, existing as a tropical cyclone from 26–29 August before weakening to a remnant low and dissipating by 3 September. The storm moved generally west-northwestward and then westward over the central-eastern Pacific during its lifetime, tracking away from the coast of Mexico and well over open water. Irwin did not make any landfalls. There were no coastal watches or warnings issued for the storm, and no ship or land-based reports of tropical-storm-force winds associated with it. Irwin reached a maximum sustained wind speed of 40 knots (about 46 mph) with an estimated minimum central pressure of 998 millibars. At its peak it was a minimal tropical storm (below hurricane strength). Because the storm stayed over open water and did not approach the coast, recorded storm surge impacts are not applicable. The NHC report did not list measurable coastal surge heights or notable rainfall totals for named cities or counties tied to Irwin. There were no reports of casualties or damage associated with Irwin. The report notes no direct fatalities and no reported destruction linked to the storm. Noteworthy items include that long-range forecasts of Irwin’s genesis were poor but shorter-term genesis probabilities improved quickly, and no watches or warnings were needed. Official track forecast errors for Irwin were larger than recent 5-year averages, while intensity forecast errors were smaller than the recent averages; however, the sample size for verification was too small for robust comparisons.