At 2014z the MXX radar showed a line of convection extending to the southwest of the radar location. SRM depicts convergence along the line but it is limited since it is down the radial. There are some notches in the reflectivity, and some wiggles in the convergence line, but there are not direct areas of rotation at this time.
The single radar azimuthal shear supported the idea of a convergent line with a corridor of slightly positive values along the line.
Stepping ahead 5 min some changes appear to be ongoing immediately to the SSW of the radar. The low-level reflectivity depicts that there is some discrete nature to the cell on the northern portion of the line. Of note, this does appear the be occurring near a surface low per the analysis, and upstream of a tornadic supercell. At this same time a kink does develop within the convergence line on the low tilt SRM.
At the same time, the AzShear product shows some enhanced values at the northern end of the line that have become somewhat discrete from the remainder of the line. However, there are some enhanced values immediately south of the aforementioned area.
Advancing ahead about 2 min, the two areas become more enhanced in the AzShear product. At the same time the SRM does continue to show a kink in the line with the northern area of interest, and some weak and broad circulation on the southern area of interest.
At this time, it is plausible to at least draft a polygon for a tornado warning based on the combination of increasing azimuthal shear and a favorable low-level environment. By 2024z the southern area of interest on the azimuthal shear has become dominant, and there is now a circulation on the 0.5 SRM. The reflectivity also shows high values associated with this circulation. In my opinion, using all three sources of information a tornado warning should be issued at least by this time.
A tornado would develop out of this line shortly thereafter about 2727z and would be rather long-lived. After examining this particular storm in this case I see the single radar azimuthal shear as a ‘confidence builder’ that can be used along-side reflectivity and base velocity or SRM. The azimuthal shear product shows potential in highlighting particular areas of interest, which may provide a few additional minutes of lead-time.