Real-time Radar-based Flash Flood Forecast System in the U.S

This presentation will describe the Flooded Locations and Simulated Hydrographs (FLASH) project that has been designed to develop, evaluate, and transition the latest rainfall-driven flash flood prediction tools to the National Weather Service (NWS). The FLASH system is based on NEXRAD radar-based rainfall estimates from the Multi-Radar Multi-Sensor (MRMS) system, providing mosaicked rainfall rates at 1-km/2-min resolution across the conterminous U.S. Products include rainfall average recurrence intervals (ARIs), ratios of rainfall to flash flood guidance (FFG) values, and simulated streamflow ARIs from a distributed hydrologic modeling framework.

FLASH skill is assessed using a dataset of over 88,000 observed streamflow events as measured by US Geologic Survey (USGS) stream gauges. Qualitative evaluations have been made possible using NWS forecaster inputs through the Hydrometeorological Testbed (HMT) Hydro Experiment run during the summers of 2014 and 2015. The presentation will provide an overview of the latest advances in the FLASH project including forthcoming impact-specific products, probabilistic forecasts, and forcing from short-term precipitation forecasts.