Converting National Weather Service Deterministic Monthly and Seasonal Drought Outlooks to an Objective Format

Each month, the National Weather Service issues monthly and seasonal U.S. drought outlooks. These forecasts support drought decision-making and situational awareness for national, regional, and state governments and other stakeholders. The current drought outlook maps highlight the change in drought category from the start to the end of the forecast period. These outlooks are deterministic, meaning they provide a single, direct forecast of future drought conditions—such as whether conditions will improve, persist, or worsen—based on expert forecaster assessment rather than a range of statistical probabilities.

This project’s goal was to improve the National Weather Service deterministic monthly and seasonal drought outlooks and services by automating the production and verification process, converting the outlooks to an objective format, and using these in the development of probabilistic drought outlooks. Developing deterministic outlooks for short-term and long-term drought can support agricultural crop planning, and the long-term drought outlooks can support hydrologic applications and water resource management. 

To do this, the research team developed an objective drought monitor to represent current drought conditions for the U.S. drought outlooks. The previous deterministic drought outlooks used the U.S. Drought Monitor as a starting point. To integrate various drought forecast information, researchers used newly developed objective tools at the National Weather Service to blend forecasts made at different lead times. Finally, the researchers revamped the format and presentation of the outlooks based on findings from the social science component of this project.

This work is part of a broader NIDIS-supported research effort to  improve NOAA National Weather Service drought outlooks. For more information, please contact Amanda Sheffield (amanda.sheffield@noaa.gov).