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In 2012 the NWS Central Region identified five offices to begin the impact based convective warning experimental product to better communicate threats to partners and constituents. The “Impacts-Based Warnings” demonstration was well received and the demonstration was expanded to all 38 Central Region offices in the spring of 2013. The positive feedback is supporting a continued expansion in the spring of 2015 to include 19 Southern Region offices, 7 in Eastern Region and 3 in Western Region.




Any effort to change core convective warning products must operate under tight restrictions, including time constraints and procedural limitations. In addition, any radical changes to the convective warning products would demand a rather large adjustment by core customers and partners, and a massive public education effort. Therefore, this demonstration will work within the boundaries of the well-established weather enterprise infrastructure to ensure easy absorption into mass communication channels.

The demonstration will build upon pre-existing Central Region efforts to employ “event tags” at the bottom of each warning for severe thunderstorm and tornado warnings. The additional tornado event tags will have tornado threat information attached to them as a quick means to provide users and partners with potential high impact risk signals that prompt faster risk assessment and protective action.



The Impact Based Warning experimental product began in 2012. Positive feedback is supporting a continued expansion in the Spring of 2015 to now include 38 offices in Central Region, 19 in Southern Region, 7 in Eastern Region and 3 in Western Region.

Full list of offices and contact information


Project Goals

  • Provide additional valuable information to media and Emergency Managers

  • Facilitate improved public response and decision making

  • Better meet societal needs in the most life-threatening weather events


Intended Outcomes


  • Optimize the convective warning system within the existing structure

  • Motivate proper response to warnings by distinguishing situational urgency

  • Realign the warning message in terms of societal impacts

  • Communicate recommended actions & precautions more precisely

  • Evaluate ability to distinguish between low impact and high impact events


Warnings enhanced by:


  • Improving communication of critical information

  • Making it easier to quickly identify the most valuable information

  • Enabling users to prioritize the key warnings in your area of interest

  • Providing different levels of risk within the same product

  • Enabling the NWS to express a confidence level of potential impacts

  • Highlighting storms that are particularly dangerous

  • Allowing users and vendors to develop apps and tools for the public and broadcast meteorologists to better communicate areas of increased risk


This project will be evaluated by:


  • Social science research groups and National Weather Service

  • Using focus groups and surveys

  • Media partners

  • Emergency Management

  • Public

  • NWS Forecasters


Examples of Impact Based Warning Tags


Example - Tornado Warning

Tag: Radar Indicated or Observed

Radar Indicated: Evidence on radar and near storm environment is supportive, but no confirmation.
Observed: Tornado is confirmed by spotters, law enforcement, etc.


Click on the images to enlarge

note: Red highlighted areas indicate changes


Example  - Tornado Warning

Tag: Considerable

When there is credible evidence that a tornado, capable of producing considerable damage, is imminent or ongoing.



Click on the images to enlarge

note: Red highlighted areas indicate changes
note: After 2012 feedback, "Considerable" takes the place of "Significant" in the 2013 Impact Based Warning Products



Example - Tornado Warning

Tag: Catastrophic

When a severe threat to human life and catastrophic damage from a tornado is occurring, and will only be used when reliable sources confirm a violent tornado.



Click on the images to enlarge

note: Red highlighted areas indicate changes


Example - Severe Thunderstorm Warning

Tag: Tornado Possible

A severe thunderstorm has some potential for producing a tornado although forecaster confidence is not high enough to issue a Tornado Warning.



Click on the images to enlarge

note: Red highlighted areas indicate changes