The generation of increasingly accurate quantitative precipitation forecasts (QPFs) has been identified as a top priority of the National Weather Service (NWS) and United States Weather Research Program (USWRP). The primary applications of QPFs are:

• Flood forecasting
• Water resource management
• Prediction of significant snowfall

In light of the devastating socioeconomic impacts of flash and river flooding and significant snowfall, QPFs have emerged as a critical facet of the end-to-end forecast process. Timely and accurate flood and winter storm forecasts are essential for the preservation of life and property. In an average year, the number of fatalities and property damage owing to flash and river flooding exceeds that for all weather-related natural phenomena. Although the death toll associated with heavy snow events is typically small, heavy snow can cripple transportation and often has a prolonged economic impact.

Improving QPF and its effect on flood forecasting and water resource management is being recognized as an immense challenge, and will require that the academic and research communities be engaged through the Collaborative Science, Technology, and Applied Research Program (CSTAR) and the United States Weather Research Program (USWRP). Progress in QPF, especially in flash-flood forecasting, will require better understanding of cloud microphysical processes and of land-surface-atmospheric interactions, improved measurements of atmospheric water vapor, better understanding of the dynamics of mesoscale convective systems, better parameterizations of cloud turbulent and microphysical processes, and further development of mesoscale numerical models.

In addition to the many scientific issues relating to QPF, there are also issues in provision of improved, real-time service to users, not the least of which involves the interaction of the important components of the modernized National Weather Service (NWS), including the National Centers for Environmental Prediction (NCEP), the Weather Forecast Offices (WFOs), and the River Forecast Centers( RFCs) that constitute an end-to-end forecast process. Several years ago, a Hydrologic Information Working Group was reformed to determine requirement for the production and use of QPF in these NWS components. An operations concept was developed by this working group for the production and use of quantitative precipitation information was developed in the modernized NWS. The next task is to develop a QPF implementation plan based on these concepts which accounts for the role of NCEP Service Centers, the WFOs and RFCs, and the implementation of Advanced Weather Interactive Processing System (AWIPS.)