A tropical storm is a tropical cyclone with maximum sustained winds of 63–118 km/h (34–63 knots). It is the stage at which the system receives a proper name (Alex, Bret, etc.) from WMO lists for each ocean basin.
Structure and evolution
It features a well-defined closed circulation, organised rain bands, and deep convection, but has not yet developed a clear eye. If winds exceed 118 km/h, it is classified as a hurricane (Atlantic/East Pacific) or typhoon (West Pacific). Tropical storms can cause torrential rain and flooding even without reaching hurricane strength.