When NEM setting.

15.10.2013 /15Z upper wind

15.10.2013 / 12Z lower wind

The current upper level winds are predominantly South Easterly which can be reciprocated by North Westerly winds  in lower levels from ground.  [With respect to TN and South peninsula] This indicates that SWM is still in force.
SW [to] Westerly [to] NW [to] Northerly and then to NEly is the reversal pattern. However the reversal sometimes may occur very rapidly. The prolonged SWM may lead to frequent formations of low / depressions / cyclones in the Bay and indirectly help to boost NEM rainfall. 
What ever it may be we are getting rainfall.

Chennai - 6:20pm, sharp showers now over Polichalur zone.
"Upper level winds are from east"