Maximum sustained wind 50% of the geostrophic wind speed aloft; while over open water or ice, the reduction is between 10% and 30%. In most basins, maximum sustained winds are used to define their category. In the Atlantic and northeast Pacific oceans, the Saffir–Simpson scale is used. This scale can be used to determine possible storm surge and damage impact on land. In most basins, the category of the tropical cyclone (for example, tropical depression, tropical storm, hurricane/typhoon, super typhoon, depression, deep depression, intense tropical cyclone) is determined from the cyclone's maximum sustained wind. Only in Australia is this quantity not used to
Tropical Storm Emilia (2006) storm briefly became disorganized, with the low-level circulation becoming ill-defined. Around the same time, Emilia passed about 175 mi (280 km) southwest of Manzanillo, which was its closest approach to southwestern Mexico; it is believed to have caused tropical storm force wind gusts along the coastline. Later that day, after turning west-northwestward, the convection increased markedly as an eyewall began to form. Operationally, it was estimated to have reached winds of 70 mph (115 km/h), and it was forecast to continue strengthening to attain Category 2 status on the Saffir-Simpson scale. However, the NHC later re-assessed Emilia as reaching peak