Some NWS forecast offices, such as the one serving the Des Moines, Iowa metropolitan area, have created standardized criteria and purpose for the usages of the heightened wording. Because data about the tornado and its exact path are often ascertained after the initial tornado warning is issued, this designation is usually added to the Severe Weather Statement (SAME code: SVS) that is used to follow up a tornado warning.
Some NWS offices, like the one covering the Des Moines, Iowa region, have established standardized criteria and purposes for employing enhanced language. As information about the tornado and its precise course is usually obtained after the initial tornado warning is issued, this label is typically added to the Severe Weather Statement (SAME code: SVS) that follows up a tornado warning.