NOUS41 KWBC 261555



Service Change Notice 18-45

National Weather Service Headquarters Silver Spring MD

1155 AM EDT Thu Apr 26 2018


To:         Subscribers

            -NOAA Weather Wire Service

            -Emergency Managers Weather Information Network


            Other NWS Partners and Employees


From:       Terrance J. Clark

            Director, WSR-88D Radar Operations Center


Subject:    WSR-88D Low Elevation Angle Field Test to begin on

            or around July 2, 2018 at Medford, OR, and San

            Francisco, CA


The Radar Operations Center will begin the Low Elevation Angle

Field Test at Medford, OR (KMAX) and San Francisco, CA (KMUX) on

or around July 2, 2018. The test will continue for approximately

one year. During the test period, the radars will operate

standard Volume Coverage Patterns (VCPs) using a supplemental

low elevation angle of +0.2, 0.0, or -0.2 degrees. Only one

supplemental elevation angle will be used at a time. The

operators will have the ability to switch between +0.2, 0.0, and

-0.2 angles during successive volume patterns. Upon the

conclusion of the test, one of the three angles will be chosen

as the permanent supplemental angle.


The Supplemental Adaptive Intra-Volume Low-Level Scan (SAILS)

feature uses the lowest elevation available, which will be the

active supplemental angle (+0.2, 0.0, or -0.2) instead of +0.5.

The Mid-Volume Rescan of Low-Level Elevations (MRLE) feature

will also use the supplemental low elevation angle, but will

still use +0.5 as part of the lowest 2, 3, or 4 elevations.


Since December 2017, KMUX has been operating with an angle of

+0.2 degrees:


Environmental assessments have determined a Finding of No

Significant Impact (FONSI) at both KMAX and KMUX. These

assessments are available online:


For questions or comments, please contact:


      Jessica Schultz

      NWS Radar Focal Point

      Radar Operations Center


National Service Change Notices are online at: