QUANTITATIVE PRECIPITATION FORECASTING - REPORT OF THE 8TH PROSPECTUSDEVELOPMENT TEAM, US WEATHER RESEARCH-PROGRAM

Quantitative precipitation forecasting (QPF) is the most important and significant challenge of weather forecasting. Advances in computing a nd observational technology combined with theoretical advances regardi ng the chaotic nature of the atmosphere offer the possibility of signi ficant improvement in QPF. To achieve these improvements, this report recommends research focusing on 1) improving the accuracy and temporal and spatial resolution of the rainfall observing system; 2) performin g process and climatological studies using the modernized observing sy stem; 3) designing new data-gathering strategies for numerical model i nitialization; and 4) defining a probabilistic framework for precipita tion forecasting and verification. Advances on the QPF problem will re quire development of advanced ensemble techniques that account for for ecast uncertainty, stemming from sampling error and differences in mod el physics and numerics and development of statistical techniques for using observational data to verify probabilistic QPF in a way that is consistent with the chaotic nature of the precipitation process.