NOUS41 KWBC 181804  



Technical Implementation Notice 11-38 Amended

National Weather Service Headquarters Washington DC

205 PM EDT Thu Oct 18 2012


To:         Subscribers

            -Family of Services

            -NOAA Weather Wire Service

            -Emergency Managers Weather Information Network


            -Other NWS Partners and Employees


From:       Richard J. Vogt

            Director, WSR-88D Radar Operations Center


Subject:    Amended to Extend Test Period: NWS Field Test Using

            New WSR-88D in Grays Harbor County, WA


Amended to extend the 1 year test of an additional scan angle less than 0.5 deg. elevation angle on the WSR-88D in Grays Harbor County, WA, (KLGX) for another year.


The NWS is planning to continue, for another year, the field test of an additional scan angle less than 0.5 deg. elevation (0.176 deg.) on the Weather Surveillance Radar-1988 Doppler (WSR-88D) in Grays Harbor County, WA (KLGX). The purposes of extending the test are to continue to determine the operational benefit(s) of having a lower scan angle and the effectiveness of the Clutter Mitigation Decision (CMD) algorithm to identify ground clutter.  The test will begin November 1, 2012 (i.e., no lapse in use of the lower scan angle). The software containing the new CMD algorithm is scheduled to be loaded on KLGX between late January and early February 2013.


As announced in TIN 38-11, Level III products will not include data from the lower scan angle. Thus, the product formats and contents will not change during the field test. Users will notice volume coverage pattern (VCP) durations increase by 30 to 150 seconds when the experimental additional lower scanning angle is in use.


To support the real-time and post-analysis of the impacts of the lower scan angle data, the Level II data stream will include the data from the lower scan angle when in use. The Seattle Weather Forecast Office will be able to turn the lower elevation scan on and off at their discretion.  Changes in Level II data when the additional test scan angle is being used are as follows:


- Experimental VCP numbers will increase by two, i.e., VCP11 will

  be VCP13

- Lower scan data will be the first data in a Level II file

- Lower scan will be a Split Cut


If you have questions or comments, please contact:


     Tim Crum

     WSR-88D Radar Operations Center


National Technical Implementation Notices are online at: