Usually, Southwest Monsoon withdraws from the entire country before the third week of October making conditions favourable for the onset of the Northeast Monsoon season. The Northeast Monsoon usually sets in around October 18 and lasts until the end of the month of December.
During this time, the sun starts moving towards the south and thus the northern parts of the country begin to cool at a faster pace. The winds blowing from North India to Indian Ocean are dry and cool. These winds pick up the moisture from Bay of Bengal and become warm and moist. Thus, dry cool winds merge with the moisture forming convective cells over the Bay of Bengal thereby resulting in rains.
During this season, most parts of Tamil Nadu as well as Andhra Pradesh witness most of their annual rainfall. Tamil Nadu records around 48% of its annual rainfall during the Northeast Monsoon season wherein coastal districts receive 60% and interiors record between 40% to 50% rains.
In fact, the month of November is considered to be the wettest one for Rayalaseema as well as Chennai, Tamil Nadu.
[yuzo_related]
This year, there has been a delay in the withdrawal of Southwest Monsoon thus delaying the onset of the Northeast Monsoon. The reasons for this can be attributed to the depression which was prevailing in the Bay of Bengal. Not only this, the effect of Typhoon Lan over Japan had also disturbed the flow of the northeasterly winds.
However, now, the north-easterlies have once again become strong over Bay of Bengal and the withdrawal of Southwest Monsoon is almost complete. The present situation along with models suggest that between October 26 and 28, Northeast Monsoon may hit Northern parts of Tamil Nadu as well as South Andhra Pradesh coast.
Image Credit: India.com
Please Note: Any information picked from here must be attributed to skymetweather.com
