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4 Guidelines for Assessing Possible Degradation of Service in Specific Areas The pane! conducted an assessment of the adequacy of NEXRAD coverage for the nation in terms of the "no degradation of service" requirement imposed by the Weather Service Modernization Act. Accordingly, the pane} examined the relative capabilities of the pre-NEXRAD and NEXRAD systems on a national level. In the course of this analysis the pane! identified some geographic areas where there appears to be a potential for degraded radar-detection coverage with the new system. However, the pane! deliberately did not attempt to make specific determinations as to the possible degradation of service at particular locations; nor did it conduct a site-by-site investigation of the possi- ble need for additional radars. As discussed in previous sections, service is a much more complex and subjective matter than radar-detection coverage. Many factors, apart from technical considerations, enter into decisions regarding the need for additional radars, including budgets, congressional interests, pressure from the public, and similar input. It is beyond the panel's purview to make such determinations; however, these factors, as well as economic vulnerability and impacts, are important and should be considered by the NWS. The pane! recognizes that the NWS will be pressed to make such determinations with regard to specific sites as the modernization progresses. The public concerns discussed in the following section reflect these kinds of site-specific issues. A set of general criteria are provided in Chapter 4 under "Assessment Criteria and Procedures." These criteria can be used to assess possible degradation of service in particular locations and to determine whether additional radars are warranted. CONSIDERATION OF PUBLIC CONCERNS Concern about possible degradation of services in the course of the NWS modernization program has generated considerable public comment. In accordance with a Federal Register announcement of November 4, 1994, the NWS received comments from approximately 67,000 people in the form of letters, postcards, collections of information, and signatures on resolutions and petitions. About 65,000 of these people (largely from 3 areas) signed petitions or sent form postcards as part of organized efforts to obtain additional NEXRAD coverage for their communities. In contrast, of the approximately 1,800 individually formulated letters and postcards, most (90 percent) commented on the need for continued services from their local weather office. About 10 percent provided technical data or other information about deficiencies in radar coverage that might be encountered when an existing radar was decommissioned and the coverage for an area would be provided by a NEXRAD relatively distant (usually 80 or more miles) from their community. Figure 4-! shows-the 32 areas of the nation from which public comments were received. Comments from 15 areas (solid circles) were concerned primarily with Me planned closure of a local weather office. The other 17 areas (~e open circles and 47

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Guidelines for Assessing Possible Degradation 49 the hatched area) were concerned about radar coverage or about both radar coverage and office closure. The NWS forwarded the comments to the NRC for use by the NEXRAD panel. Technical information included in the public comments was incorporated into the panel's analyses and was considered during He course of the study. ASSESSMENT CRITERIA The panel's charge included the task of "establish[ing] criteria for evaluating the adequacy of coverage of Be pre-NEXRAD and the proposed NEXRAD network and areas for decommissioning of existing radars." In response to this task, the panel recommends the following criteria and procedures for use in evaluating the adequacy of NEXRAD coverage for specific areas. The suggested evaluation criteria are as follows: I. Weather phenomena of concern to the area Are the weather phenomena of concern detectable by weather radar? 2. Degradation of radar coverage relative to the weather phenomena of concern- Do the radar-detection coverage maps for specific weather phenomenon show degraded coverage by NEXRAD? Performance of the composite system relative to the phenomena of concern-Does the composite system evaluation indicate that the new system performs as well as the old system? The suggested evaluation procedures are as follows: I. Determine the weather phenomena of concern in the area of interest. 2. Examine the relevant weather phenomena radar coverage maples) to identify regions where radar coverage of each phenomenon is reduced from what had existed with the pre-NEXRAD system. 3. Assess the composite system capability and its impact; especially on reducing the risk to life and property. The composite system elements include, but are not limited to, those listed below. characteristics of local weather phenomena; radar coverage and terrain features; data quality and availability; local spotter network and the user community; adequacy of communications within the composite system and with users; education and training for the forecasters and user community; and other composite system elements, such as ASOS, satellite data, soundings, prior RADAP IT and/or ICRAD capability, AWIPS, centralized support products and services, and similar elements. If an assessment of composite system performance and its consequences concludes that services related to radar coverage would be degraded, then there is inadequate radar coverage for the area. Wherever Were is inadequate radar coverage, the NWS should take appropriate actions to reduce the risk of adverse weather consequences to human life and property to acceptable levels. One of the options would be to determine the cost and benefits of providing the needed detection coverage for the area of concern by adding or relocating a NEXRAD or by using some other radar alternative.

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so Assessment of NEXRAD Coverage The detection coverage charts for specific weather phenomena Mat were developed by the panel, along with the suggested assessment criteria and procedures, provide a baseline for the NWS (or others) to make decisions on the adequacy of NEXRADs to meet the coverage and service requirements for specific areas. The panel's assessment criteria and procedures should be incorporated into official NWS guidelines and used in conjunction wig the requirements in P.~. 102-567.~ ~ The certification criteria for decommissioning an existing radar and consolidating weather offices were published in the Federal Register, Vol. 59, No. 41, March 2, 1994, "Rules and Regulations." These criteria included formal actions that certify and commission the supporting NEXRAD, provide adequate notification to users, provide user confirmation of associated services, and determine that the existing radar is no longer needed for service coverage of that area.