Now, the conditions are becoming favourable for the setting up of NE monsoon in TN as the SW monsoon is retreating gradually over parts of Telangana and Karnataka. It is now mentioned that NE monsoon is expected to set in over TN between 23rd and 25th of October.
Till 19th October, wet weather would be there over parts of TN and this was as per RMC in Chennai. It is known that TN has been awaiting monsoon reversal. There would be light to moderate rains that would be brought by the cyclonic circulation over south TN and neighbouring areas.
On Monday, there might be heavy rainfall in some isolated places in the Ghat Areas of Coimbatore, Theni and Dindigul etc. On Tuesday, there might be heavy rainfall in districts like Salem, Dharmapuri etc in Tamil Nadu.
For the withdrawal of SW monsoon, the weather pattern is being monitored now. This was mentioned by Met dept officials. They added that the SW monsoon might withdraw from other parts of India like Maharashtra and Telangana etc in a couple of days. The presence of cyclonic circulations has led to the prevailing of both easterly as well as westerly winds.
Development of wind shear zone:
According to Mr. S. Balachandran, additional DDG or Meteorology in Chennai, a wind shear zone would develop over the region and sustain rainfall activity. He spoke about how the onset of NE monsoon would be announced only if certain criteria were met.
The various criteria includes
- complete withdrawal of SW monsoon
- setting in of easterlies over the TN coast
- fairly widespread rain over TN, south coastal AP and nearby places
It must be recalled that the earliest onset of NE monsoon was on 5th October 1984. This was according to data from IMD from 1977 to 2020.