The inference from this is that South west monsoon may not be helpful. The hailstorms associated with it in the beginning of the season can be expected. (These inferences must be checked and observed for a minimum of 5 to 9 years) to arrive at workable factors in rainfall prediction.)
1. Tamo megha (தமோ மேகம்) – brings plentiful rains.
Part 1- http://www.tamilhindu.com/2010/01/paavai-nonbu-and-thai-neeraadal/