Graphically depicting local threat assessment and potential impact information during Peninsular Florida tornado situations

Since 1999, a local scale depiction of tornado threat covering east central and southern Florida has been provided in graphic form on the internet. This experimental product is generated daily by the Weather Forecast Offices in Melbourne and Miami and posted on their respective web sites for customer use and feedback. Over the years, the tornado threat graphic has evolved from a simple prototype version to the current version and has been favorably received by the local emergency management, media, and public. Threat assessment is based on the likelihood that tornadoes will occur, combined with the anticipated strength of the most intense tornado (e.g., tornado vs. significant tornado). A color coded map is used to communicate all the threat assessment information in an easy to understand format. By including descriptions of potential impact, the map is designed to motivate individuals to take early protective measures that are proportional to the situation even before tornado watches and warnings are issued. In real-time operations, the graphics have been produced during many notable events ranging from killer tornadoes associated with mid-latitude systems to tornado outbreaks associated with tropical cyclones. This paper will examine the insights gained by the Weather Forecast Offices at Melbourne and Miami from these events in order to support the many efforts being undertaken elsewhere, and to deliver applied research results to the several teams within the National Weather Service who are working toward a national implementation of graphical hazardous weather outlooks and hurricane local statements. This paper will discuss the use of limited vs. full automation for the generation of threat assessments; the relative contributions of expertise from national centers and local field offices; the value of standardized national definitions vs. regionalized definitions of varying impacts; and other related issues, including the need for caution when attempting to issue threat assessments that extend well beyond Day 1.