I thought the attached diagrams were interesting enough to distribute. They are hovmoellers of 850 vorticity and 200 divergence for the latitude band 15S-5S over the longitude span 20E-180E, for the period 9 Jan 2002 to 14 Feb 2002. TC Chris formed near 120E around day 25.

Note
1. the eastward group propagation with successive cyclonic- anticyclonic developments eastward (also divergence),
2. the westward phase propagation (of cyclonic vorticity maxes (weather systems)),
3. TC Chris forming as a westward propagating vorticity max meets the eastward propagating MJO(?) (- or is this just
a single process?), and
4. similar developments to 3., but upstream (and downstream) of Chris.

Would such diagrams be useful for real-time monitoring?
Did all those cyclonic vorticity maxes form into TCs?
How does the vortex spin up in such an environment?
Are there extra-tropical influences?

ND

Question for JMB on Beni : was it shear or some other process?