The HIWeather project of the World Weather Research Programme has been successful in promoting an holistic view of the warning chain from observations and forecasts through Impact-Based Warning to communication and response. Key to this has been the building up of an active interdisciplinary community of social and physical scientists working together to better understand what makes an effective warning system. Building on previous work, including in the Weather Ready Nation initiative and in the THORPEX experiment, HIWeather has developed a concept of the warning chain based on partnerships among the many actors producing, delivering and using high impact weather information. This concept has been influential in designing the response to the UN Secretary General's call for Early Warnings for All, as well as in the construction of new and improved warning systems in several countries.

The session will address this topic through a combination of invited and submitted presentations on the implications of HIWeather and other projects for the development of more effective high impact weather warnings.