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rain rate threshold on this day had the Z-R parameters been set at more appropriate values, and one should not attempt in general to control PPS overestimation by decreasing the rain rate threshold in the PPS adaptation data when such overestimation is widespread over the radar umbrella as was the case here, The PPS Adjustment algorithm was evaluated using the available gauge data to determine if it could properly correct (i.e., reduce) the radar overestimates to bring them more in-line with the gauge estimates as it is designed to do. The algorithm performed suboptimally, not due to any deficiency in the Kalman filter formulation, but instead due to the particular methodology employed in the algorithm when it forms the hourly gauge-radar pairs that are input to the filter. The algorithm did not make large enough bias corrections to the radar estimates to fully account for the observed biases because the gauge-radar pairs it generated as input were themselves biased by this procedure. The algorithm computed bias estimates that moved the radar estimates in the right direction (that is, decreasing them) as it should have, but it didn't move them far enough to bring them into satisfactory agreement with the gauges. An alternate and simpler methodology for forming the gauge-radar pairs by using the radar bin directly over the gauge was tested and found to significantly improve the algorithm's performance even though it did not totally remove all of the gauge-radar bias, The storm-total radar overestimation was reduced from 63% to 25% by running the Adjustment algorithm with input gauge-radar pairs in which the radar estimate collocated with the gauge was chosen. The one-hour basin-average radar rainfall never reaches more than one-third of the one- hour Flash Flood Guidance rainfall for the Buffalo Creek basin, yet a flash flood occurred. If the computed gauge-radar bias estimates had been applied to the radar estimates, the basin average 25