Warning system
Many of the National Weather Service's Weather Forecast Offices—primarily those located within the Central and Southern Region Headquarters—use a multi-tier impact-based warning (IBW) system of impact statements to notify the public and emergency management officials of the severity of specific severe weather phenomena. The impact statement system—initially used only for tornado and severe thunderstorm warnings—was first employed by the WFOs in Wichita and Topeka, Kansas, and Springfield, St. Louis and Kansas City/Pleasant Hill, Missouri beginning with the 2012 Spring severe weather season, eventually expanded to include 33 additional National Weather Service Weather Forecast Offices within the Central Region Headquarters in 2013, and then to eight additional offices within the Eastern, Southern and Western Regions in the spring of 2014. Effective on or around April 28, 2021, the NWS will incorporate damage threat categories, similar to those used for tornado warnings since the implementation of the Impact Based Warning system, applying to higher-end severe thunderstorms containing destructive hail size and/or wind speeds (as “CONSIDERABLE” or “DESTRUCTIVE") at the bottom of the text products for severe thunderstorm warnings and related Special Weather Statements.