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109 There are approximately 100 forecast offices in the U. S., and an individual forecaster works 1/5 of the shifts in a typical office. Assuming Forecaster A has a 20-year career, he or she will work about 4 % of the annual national average of events during the course of his or her career. Thus, for the estimated annual average of25 6 inches/hour events, Forecaster A will encounter one such event during his or her entire career. Forecaster B, on the other hand, at a national center, works 1/5 of the shifts and, thus, is on duty for 1/5 of the events every year. As a result, Forecaster B will be on duty for five 6 inches/hour events each year or 100 times as many events as Forecaster A. Thus, the relative levels of experience for both Forecasters A and B have critical implications for their roles in successfully anticipating, forecasting, and warning about flash floods. In the absence of quality guidance, a local forecaster must get the biggest precipitation event in his or her career "right" the first time, and many forecasters never get a second chance. However, even though extreme precipitation events are rare at any single location, they are relatively common from the national perspective. Thus, the national center forecasters develop significant experience in dealing with rare, extreme events in a relatively short time. As a result, the national centers have primary guidance responsibility, identifying general regions of greatest threat, while the local office has primary forecast and warning responsibility, narrowing the area of threat in short-term forecasts and identifying the exact location of extreme precipitation in warnings Brooks, Stensrud, and Mitchell Discussion The nature of flash flooding requires an understanding of the climatology of extreme precipitation. The HPD represents the most complete description of short time-scale precipitation measurements covering a significant time period over the entire United States. However, as we have seen, it still misses most of the truly large precipitation events that actually occur. The data allow us to"make reasonable estimates of the real frequency of heavy precipitation. These estimates should be of value, both for emergency managers and for weather forecasting concerns to allocate resources and plan for the inevitable flash flood events. National network radar estimates of precipitation can be used to refine the climatology presented here, although it will be years before a significantly long period of radar observations exists to allow for reasonable estimates.