Southwest Monsoon has withdrawn from entire North and Northwest India. It has also started retreating from parts of East and Central India.
As of October 5, the withdrawal line of Southwest Monsoon passes through Forbesganj, Gaya, Jabalpur, Hoshangabad, Bhavnagar, Porbandar, Latitude 21.5°N/Longitude 65.0°E and Latitude 21.5°N/Longitude 60.0°E.
The withdrawal line of Southwest Monsoon goes till about 15°N Latitude. By then we generally reach the mid of October, when Peninsular India comes under the dominance of Northeast Monsoon. Withdrawal of Monsoon process generally comes to an end by October 15.
Peninsular India has been receiving very heavy showers since the last few days. But, this spell of rainfall cannot be construed as Northeast Monsoon rains. The winter Monsoon season is not declared before October 10. All the rainfall activity seen over South Peninsula at present is a part of retreating Southwest Monsoon.
Rainfall will continue in Peninsular India for the coming days. Skymet had said earlier as well there is no clear divide between the withdrawal of Southwest and onset of Northeast Monsoon in this part of the country. First 15 days of October is considered as the overlapping period for retreat of Southwest Monsoon and incursion of Northeast Monsoon.
Occasional land and sea breeze blowing over Peninsular India are also easterlies. But, for onset of Northeast Monsoon the easterly winds will have to settle up to 5000 ft. above the sea level. Sothwesterly winds permanently get replaced by easterly winds. Moreover, there should be a good burst of rainfall over Coastal Andhra Pradesh and Tamil Nadu.
The stage gets set and permanent change of winds is brought about by weather systems originating mainly in the Bay of Bengal. The systems which develop in the Arabian have the tendency to move away from the West Coast and threaten Gujarat. The Bay of Bengal systems move inland and bring rainfall over several parts of the country.
Unlike the Southwest Monsoon, Northeast Monsoon does not have any specific date of commencement. There is no clear divide, but one process has to complete for the other one to settle in.
Click here to read the story, Monsoon Reversal: Rainfall regime to shift towards Peninsular India
Image courtesy - India Today
