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. . . NWS 11 May 2001 5. Since the western limit for the application of HMR 52 has varied from publication to publication, what is the current western limit and how was it derived? (Tomlinson) The group did not reach consensus. The NWS will examine a way to verify this assumption. Answer 5. The westen! limit for HMR 52 procedures has always been and remains the 105th meridian. This limit is not based on physical principles and is not "derived." Rather, it has been based on the requirements established first in HMR 23 and subsequently in HMR 33 and HMR 51 for those studies. 6. HMR 52 was not developed using storms considered transpositionable to the Cherry Creek drainage basin. What analysis (i.e., analysis vs opinion) has been performed to demonstrate the HMR 52 is appropriate for use for the non-orographic component of PMP for the Cherry Creek location? (Tomlinson) The group did not reach consensus. The NWS will examine a way to verify this assumption. Answer 6. Analysis of storms through their classification by type (discussed in HMR 55A, Section 2.5.3 and shown in Table 2.3) reveals that the storms at Cherry Creek and Hale in 1935 were both of the complex convective, least orographic type. This means that the same type of least-orographic, synoptic scale mechanisms in 1935 were operating at each storm location. Use of storm classification by storm type is a recognized method for transposition (see Section 2.5 and especially Section 2.5.2.2 of the Manual for Estimation of Probable Maximum Precipitation, WMO, 1986). Thus, the least-orographic characteristics of the storms at either location may be relocated to the other after appropriate adjustments for elevation. Since the storm at Hale occurred east of the 105th meridian, it was appropriate to use information about it to develop HMR 52 procedures. HMR 52 procedures may be used at any drainage east of the 105th meridian in connection with the non- orographic component of precipitation. HMR 52 does nothing to "set the level" of (non-orographic) PMP for a drainage, but simply sets out how an already predetermined PMP level will be "distributed areally." In accomplishing this task, the HMR 52 procedures ensure that levels of precipitation within a drainage will never exceed PMP levels for any subarea of that drainage. The predetermined levels of PMP that must apply to a given drainage at storm area sizes near the actual area of that drainage, are reduced by HMR 52 when it takes the drainage's 8