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, , Day 2, Day 3" in Table 5 might have confused some since the text ofNWSI995 did not take time to explain that a "Day" did not have to begin and end at midnight. The daily period being referred to in NWS 1995 is, by convention, an unconstrained period oftime and could begin at anv time, That being said, it is in the realm of likelihood to have the most intense 6 hours of precipitation begin at or somewhat before I 0 P~, We do not agree completely with the analysis presented in paragraph 5 on page 12, With a front immediately south of the Cherry Creek target area during the day, light precipitation produced by upslope flow could exist along with increasingly destabilized columns of air aloft, The approach of forcing energy from the west or southwest subsequently could act to relocate the front north of the target area, thereby making the entire atmospheric column from the surface to the tropopause available for overturning as well as for dynamically forced convection, The larger hourly amounts in Table 5 ofNWS 1995 immediately preceding the most intense 6 hours of precipitation could be repositioned to follow that period, with some of the smaller amounts from other times replacing them. While such a selection might be meteorologically somewhat more likely, such a rearrangement HAS NO BEARING upon the values to be assigned to the most intense I-hour, 6-hour, "., or n-hour accumulated basin averaged depths from which the hourly increments were extracted, The basin averaged amounts shown in Table 4 ofNWSI995 are probable, These amounts were developed from information found in HMR 55A (along with supporting documents) which was produced according to rules adopted over decades of practice. Any sequence of hourly amounts consistent with Table 4 would be acceptable for use in developing the probable maximum flood and need not mimic the sequence found in any one storm or collection of storms. We do not agree with the characterization that "The NWS study did not identify this discrepancy." The values shown in Table 4 do not depend on a specific storm chronology. The depth- area-duration relations developed for HMR 55A, which played a role in creating the values found in Table 2 ofNWS1995, and which in turn determined what the values of Table 4 would be, were based on comparisons with known extreme storms, See Chapter II ofHMR 55A for details on how these relationships were developed, It appears that the authors ofIR#1 believe that if one gets a storm's hourly amounts correct, the cumulative amounts will follow correctly. We agree, however if you "miss" anyone ofthe hourly amounts, you will either underestimate or overestimate cumulative PMP amounts for one or many durations. We would try to discourage anyone from adopting such a "bottom-to-top" methodology. The NWS approach is to estimate the cumulative PMP first and then arrive at possible temporal distributions. 9