including any plausible alternative approaches for flash flood forecasting; and
identify lessons that could benefit forecasters, facility planners, and decision makers as they deal with other NEXRAD installations and similar instruments deployed in the future.
The Committee to Assess NEXRAD Flash Flood Forecasting Capabilities at Sulphur Mountain, California, carried out this requested study during the first half of 2004. In doing so, the committee assessed the Sulphur Mountain radar and its availability, coverage, and use in flash flood forecasting; it also considered how this example could be applied to other NEXRADs located in regions of complex terrain for improved flash flood forecasting and warning. This report is the result of the considerations and deliberations undertaken by the committee.
For the interested reader, Chapters 2 through 4 provide technical background information relevant to this study. Chapter 2 provides basic information about the physical processes of flash floods. Chapter 3 provides an overview of the NWS, its modernization effort, and the general process undertaken by NWS forecasters to issue flash flood forecasts, watches, and warnings. An extensive description of NEXRAD is presented in Chapter 4, including discussions of the radar characteristics and the network and its use for precipitation estimation.
The reader more interested in the committee’s analysis, findings, and recommendations should see Chapters 5 through 9. Chapter 5 presents special challenges of low-level radar coverage in regions of complex terrain. Chapters 6 and 7 look specifically at Los Angeles and Ventura Counties, with the warning process presented in Chapter 6 and the analysis of the Sulphur Mountain radar and the flash flood warning performance of the Los Angeles-Oxnard NWS office in Chapter 7. Chapter 8 outlines potential improvements in flash flood warning capabilities, and finally, Chapter 9 provides the concluding thoughts of the committee.