Slide 19 of 45
In this chart aqua colored contours show absolute vorticity…with a cyclonic tongue extending from northwestern Argentina into Bolivia. Rather than concentrating on the actual value of the vorticity contours, it is better to assess the changes with respect to time/and transport. Advection of vorticity is thern a better indicator, with cyclonic transport (NVA in the Srn Hemisphere) coded red, and anticyclonic transport (PVA) coded blue.
This results in two clearly marked perturbations streaking across Nrn Chile and Argentina…providing the triggering mechanism for the developing MCC.