A Path Toward Short-Term Probabilistic Flash Flood Prediction

Abstract There are ongoing efforts to move beyond the current paradigm of using deterministic products driven by observation-only data make binary warning decisions. Recent works have focused on severe thunderstorm hazards, such as hail, lightning, and tornadoes. This study discusses one first steps toward having probabilistic information combined with convective-scale short-term precipitation forecasts available for prediction flash flooding. Participants in Hydrometeorology Testbed–MRMS Hydrology (HMT-Hydro) experiment evaluated several probabilistic-based hydrologic model output from Flooded Locations Simulated Hydrographs (PRO-FLASH) system during experimental real-time operations. Evaluation flood performance product surveys highlighted how forecasters perceived biases within different approaches influenced warnings that were verified versus those unverified. The incorporation Warn-on-Forecast System (WoFS) ensemble into PRO-FLASH generation provided an opportunity evaluate coupling subhourly modeling at time scale through archived case simulations. addition WoFS resulted increase lead time, including four events ≥29 min additional but increased probabilities false alarms. Additional feedback participants insights application decisions, expectations confidence evolved forecast can positively influence communications potential