Final answer:
The characteristic signature of a tornadic thunderstorm in radar images includes a hook-shaped echo indicating a rotating mesocyclone and potentially high winds from descending funnel-like clouds.
Step-by-step explanation:
The characteristic signature of a tornadic thunderstorm, often called a supercell, in a radar reflectivity image includes a well-defined, hook-shaped echo. This hook echo is indicative of a rotating updraft called a mesocyclone and is a result of the strong rotation within the storm due to wind shear at different altitudes. Doppler radar can also show a strong velocity couplet when a tornado is present, highlighting areas of significant wind divergence and convergence, which suggests turbulent motion consistent with a tornado's vortex.
A large difference in pressure between two areas is an important criterion for generating storm reports, including reports of tornadoes. Furthermore, tornadoes descend from clouds in funnel-like shapes that spin violently, with the potential to produce extremely high winds and cause significant damage. They are often associated with violent weather events which, according to Figure 8.13, can be attributed to Earth's tilted axis of rotation, its moderately rapid rotation, and the presence of vast oceans.