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Fig. 18.13 A schematic summary of VORTEX2 data analysis of the Goshen, Wyoming
tornadogenesis case . Schematic summarizing the evolution of a tornadic storm during its pre-
tornadic phase. The clocks represent the time until tornadogenesis. Regions of significant cyclonic
(anticyclonic) vertical vorticity are indicated by the purple ( yellow ) shading. Dark gray shading
encloses even larger cyclonic vertical vorticity. The descending reflectivity core is indicated by the
green shading. Surface gust fronts are analyzed using blue lines . Streamlines are shown in black
arrows . Vortex lines are shown in gray streamers, with the sense of rotation indicated by the gray
arrows .In( d ), the downward-pointing arrow indicates the occlusion downdraft (From Markowski
et al. ( 2012a , b ))
in Fig. 18.13 , the wrap-around mechanism worked actively by the right-hand side
vortex in Fig. 18.13 corresponding to the lower and upper mesocyclones in Fig. 18.4 .
Also, it is noted that the shaded area of high vertical vorticity of Fig. 18.13 covers
both areas of the upper-level and the low-level mesocyclones, which may be formed
by the baroclinicity generated between entropic source and sink and upward tilting
horizontal vortex, respectively. It suggests that vertical superimposition of their
phases seems a key of tornadogenesis (Fig. 18.14 ).
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