The first half of October is the overlapping period for retreat of Southwest Monsoon and incursion of Northeast Monsoon in the Southern Peninsula. The stage gets set and change is mainly brought about by weather systems originating in the Indian seas.
In the northern parts of the country we generally see the establishment of anti-cyclone over Rajasthan. This brings about the reversal of wind pattern and accentuates the withdrawal process of Southwest Monsoon from North and Central India.
Northeast Monsoon
Unlike the Southwest Monsoon, Northeast Monsoon does not have any specific date of commencement. It mainly affects five sub-divisions of South India, namely Tamil Nadu, Kerala, Coastal Andhra Pradesh, Rayalaseema and South Interior Karnataka.
With the commencement of the Northeast Monsoon season, total reversal of winds take place from the Indian seas and Peninsular India.
Northeast Monsoon Forecast
At there is a weather system brewing up in the Andaman Sea. It could most likely become a significant one, developing first into a depression and further into a deep depression. Another system will come up in the Lakshadweep region very soon. Both these systems will take about a fortnight to complete the sea travel and finally be instrumental in the commencement of Northeast Monsoon.
Another pre-requisite is a good burst of widespread rainfall over Tamil Nadu and Coastal Andhra Pradesh. Skymet will keenly follow the transition from Southwest to Northeast Monsoon.
Image courtesy - The Hindu