Major weather models are constantly picking up a circulation in north Andaman sea, which is likely to become first Pre NEM system of the year. Both GFS and ECMWF are intensifying it into a Depression and bringing it towards south Orissa and North Andhra Pradesh arround October 12-13. As there is no proper support from planetary waves and owing to moderate to high shear, this system may not intensify much.
An another circulation is seen emerging from south china sea into north Andaman sea immediately after 1st one which is to be closely monitored.
NEM onset over TN
With back to back lows emerging into North Andaman sea it is difficult to say when NEM will set in over TN. 1st system direction is confirmed, while the second system’s formation, movement will decide the date of onset of NEM over TN.
MJO the master wave
NEM power house MJO ( Madden Julian oscillation) is not seen entering into NEM/TN favorable phase of 2/3 until 20th of October, which is a worrying factor.
Chennai and TN rains
Though the 1st system is forecasted to move towards AP and orrisa, when it nears the shores of AP, it could possibly cause Convergence of northwesterly winds over North coastal TN and North interior TN thereby causing heavy thunderstorms. Chennai can look out for possible thunderstorms between October 9-13.