Supercells - Severe Convective Storms and Tornadoes: Observations and Dynamics - page 206

Figure 4.27. Classic supercell. (Top) May 31, 1990 in the northern Texas Panhandle. The area
to the right of the tornado is translucent, but has widely spaced hail falling, which on radar
appears as an area of high reflectivity. (Bottom, left) Clear slot in eastern Colorado on June 8,
1994, as seen from an NOAA P-3 aircraft; (bottom, right) clear slot over Redesdale, Victoria,
Australia, on October 12, 2010, which is the mirror image of a clear slot in the Northern
Hemisphere (cf. with the image to the left in Colorado) (photographs by the author, except the
last one, which is courtesy of John Allen).
a hypothesis may explain why LP and HP supercells are sometimes observed in
close proximity (when the environments are similar) or why LP storms sometimes
become transformed into HP supercells. A summary of the types of supercells is
given in Figure 4.28.
4.4 THE PRODUCTION OF MID-LEVEL ROTATION
When a buoyant updraft rises in an environment of vertical shear, which
represents horizontal vorticity ( Figure 4.29 ), some of the latter is converted into