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. . . NWS 11 May 2001 8. Table 14 in HMR 52 provides a list of the storms used to develop the within/without curves. Averages of values from these 29 storms were used and smoothed. It is stated that the authors of HMR 52 chose not to consider any regional variation that may exist in these storm ratios. They additionally state that they consider this conclusion (i.e., not to consider regional variations) to be justified at this time (1982) but add "however, future study should investigate regional variation in depth-area relations" (HMR 55A, Section 11.3, page 153 (ref. added)]. In the HMR 55A discussions related to Depth Area Duration Relations (Section 11), it states that "DAD relationships in the non-orographic regions west of the HMR No. 51 region should decrease with increasing area size at an even faster rate than they do within the HMR No. 51 region." In light of these identified variations west of the HMR 51 region and the suggestion that future studies should investigate regional variations in depth-area relations, why were not regional variations in the within/without curves considered in the site-specific PMP study for Cherry Creek? (Tomlinson) The group did not reach consensus. The NWS will examine a way to verify this assumption. Answer 8. The storms selected to develop the within-without relations in HMR 52 were ones in which, for a standard area size, the moisture-maximized average depth of precipitation came within 90% of PMP for that storm location. A regional variation from the "universal" within-without relations of HMR 52 would have to be based on storms of the same magnitude, and there would have to be a number of them to justify a regional departure from the "universal" relations. Neither condition was met when The Study was prepared, nor are they now. The second statement quoted here in full is, "This suggests that DAD relationships should decrease with increasing area size at an even faster rate than they do within the HMR 51 region." This sentence needs to be coupled with the previous sentence in HMR 55A, Section 11.3.1, page 153. This sentence reads, "Presumably, this is due to the difficulty of sustaining large area moisture inflows as the western edge of that study (l05th meridian) is approached." The Cherry Creek basin is completely east of the 105th meridian. This would indicate the second quote in the question above has no bearing upon The Study. HMR 55A is saying the storms to be investigated are storms west of the 105th meridian, not east of the 105th meridian. 10