QIWI—A Web-Based Flash Flood Monitoring Tool

The Areal Mean Basin Estimated Rainfall (AMBER) algorithm uses WSR-88D reflectivity data to estimate average rainfall accumulations in small watersheds. Its utility has been demonstrated in the Honolulu, HI, Pittsburgh, PA, Tulsa, OK, and Sterling, VA National Weather Service Forecast Offices (NWSFOs). AMBER alerts forecasters when basins are receiving heavy amounts of rainfall relative to Flash Flood Guidance (FFG) values. The value of AMBER as a flash flood monitoring tool is limited by uncertainty in WSR-88D rainfall estimates and the applicability of county-wide or region-wide FFG values to small basins. In response to these potential shortcomings, a real-time system has been devised to ingest improved radar estimates of precipitation from QPE SUMS algorithm. These accumulations are averaged in small basins (i.e., typical areas are 20 mi²) and fed into a web-based AMBER display system called QIWI (QPE SUMS Interactive Web Interface). The QIWI interface includes average basin rainfall in addition to terrestrial attributes for each basin. Basin attributes include basin area, maximum elevation difference, potential infiltration rate, and potential runoff rate. These derived parameters assist forecasters in determining the flash flood potential of a basin given heavy rainfall. Results from QIWI's real-time deployment in Arizona NWSFOs during the summer of 2000 will be presented.