An Updated Radar-Based Storm Rotation Climatology for the CONUS

Beginning in 2012, a partnered effort titled the Multi-Year Reanalysis of Remotely Sensed Storms (MYRORSS) was started to process the WSR-88D archive through the Warning Decision Support System Integrated Information (WDSS-II) software suite to produce three dimensional mosaics and derived severe weather products on a CONUS latitude-longitude grid with 0.01 x 0.01 degree spacing. One severe weather product that is derived is azimuthal shear calculated using the linear least-square derivative technique (LLSD), which is created over two merged composite layers of 0-2 km AGL and 3-6 km AGL. In 2014, an initial examination of the processed azimuthal shear data revealed some data issues related to the simplifications of the LLSD equations involved in the azimuthal shear calculation. An updated version of the azimuthal shear algorithm with improved LLSD equations was completed in 2016 with subsequent reprocessing of the product for the MYRORSS dataset beginning in 2017. A presentation of the updated azimuthal shear processing within MYRORSS will be shown, including improvements of velocity dealiasing and azimuthal shear feature tracking, as well as the existing challenges related to the updated derived data. Discussions on future work and initial climatological results will also be included.