Toward the next generation of seasonal drought outlooks

The Climate Prediction Center (CPC) has published U.S. seasonal drought outlooks since the spring of 2000. The product provides indications of the general trends in drought over the ensuing 3 to 3 ½ months, and is issued twice each month. The Outlook depicts the likely change in drought status in terms of improvement or persistence/intensification, and includes areas where drought is expected to develop. Although this format appears to be adequate for the general public, and verification scores show consistent superiority over simple persistence, the lack of quantification makes it difficult to incorporate in decision-making by agricultural interests and water supply managers. As a result, CPC is working with a number of internal partners across NOAA and external partners (e.g., other agencies, academia and the private sector) to develop quantitative drought forecast products to complement the existing Outlook format. A major component of this project is the use of the North America Land Data Assimilation System (NLDAS), which provides near real-time hydrologic simulations across the continental United States with a spatial scale of 1/8th degree. Hydrologists at Princeton University, the NCEP Environmental Modeling Center (EMC), the University of Washington, and the NWS River Forecast Centers have been incorporating forecast data in the NLDAS models from various sources, including historic weather outcomes, seasonal dynamical forecast models, and the CPC temperature and precipitation forecasts to create probabilistic forecasts of soil moisture and streamflows. CPC is partnering with these organizations to evaluate existing products, consolidate them, and transition them to effectively depict national drought probabilities. A proposed suite of forecast products, including depictions of probabilities for total drought, agricultural drought, and hydrologic drought, will be discussed.