Emergency managers (EMs) play a critical role in communicating severe weather and tornado warnings to the public, and as such are an integral component of a weather warning system. However, communicating the uncertainty of when, where or if a tornado may hit remains a great challenge for EMs. This study employs a mixed methods approach using survey and focus group data with Oklahoma and Texas Emergency Managers. The goal of this study is to identify: 1) the types of weather warning systems used by EMs to disseminate warnings to the public including the advantages and disadvantages of those systems; 2) EM warning practices including preferred lead times for warnings; and 3) the use of storm spotters in EM decision-making. Results indicate weather observing spotters are key sources of verification data. With respect to warning the public about tornado threats, outdoor warning sirens are widely used but EMs stress that redundant warning methods are critical as not all of the public can hear outdoor warning sirens. Emergency managers with the ability to warn by subregion are in general not employing this capability. Implications of this work are that technological, policy and educational interventions will be required to take advantage of warning by subregion. These findings are related to the development of a new radar system being developed by the Center for Collaborative Adaptive Sensing of the Atmosphere (CASA), so that this new technology can be designed to reduce uncertainty in the EM decision-making process.->