Evaluation of a Radar-Based Multi-Scale Storm Tracking Technique for Very Short-Term QPF

Flash flood warnings require accurate quantitative precipitation estimation (QPE). To increase the warnings’ lead-time, a short-term quantitative precipitation forecast (QPF) is also needed. Numerical weather prediction models can provide QPFs, although the model forecasts in the first several hours often suffer from “spin up” issues and have relatively low accuracy. Radar extrapolations have been used for qualitative storm nowcasts for decades but have not been commonly used for QPF. This study examines a radar-based multi-scale storm tracking technique and its potential capability for 0-3hr QPF. The tracking scheme segregates radar observed precipitation fields into storm entities at different scales and estimates the storm movements for each scale. Radar QPE fields are then extrapolated forward in time assuming a steady movement. The extrapolated/forecast precipitation fields are validated with the radar observed QPEs. This study examines the sensitivity of the radar extrapolation QPF to various parameters in the storm segregation, tracking and extrapolation processes. Preliminary results from case studies will be presented at the conference.