The NWS end-to-end quantitative precipitation forecasting process: Status and future plans

The primary mission of the National Oceanic and Atmospheric Administration's (NOAA's) National Weather Service (NWS) Hydrologic Services Program is to provide (1) advanced, short-term river and flood forecasts and warnings for the protection of life and property, and (2) basic hydrologic forecast information for the nation's economic and environmental well-being, including extended-range forecast information for water resource management. The End-to-End (ETE) Quantitative Precipitation Forecasting (QPF) process is comprised of many steps which include collecting and assimilating observations, running numerical weather prediction (NWP), statistical, and hydrologic models, preparing forecasts and warnings, and coordinating these products with a diverse user community.

In support of these hydrometeorological missions of the NWS, the operational ETE QPF Process has been streamlined and enhanced to more efficiently utilize resources and capitalize on recent technological and scientific advances. Recent and planned improvements to QPF process are based primarily on requirements and recommendations outlined in (1) the NWS strategic planning document published in 1999 and entitled "The Modernized End-to-End Forecast Process for Quantitative Precipitation Information: Hydrometeorological Requirements, Scientific Issues, and Service Concepts," and (2) two formal assessments of the resources utilized and the value added at each step of the QPF process which were conducted for the period November through March of 1998-1999 and 1999-2000, respectively. An overview of enhancements in NWP, statistical modeling, forecaster input, verification, and training, as well as an update of NWS demonstration efforts to transition to probabilistic QPF will be presented. These modifications to the forecast process yield and an operational framework which is more efficient and which more effectively couples advanced meteorologic and hydrologic prediction to improve the accuracy, reliability, temporal span, and timeliness of hydrometeorological forecasts and warnings. The projected generation of probabilistic QPFs and their incorporation into the NWS River Forecast System to prepare Advanced Hydrologic Prediction Services-based guidance, will enable forecast offices to ultimately provide user-requested river and flood warning and forecast products which quantify forecast uncertainty and convey risk.