This year, withdrawal of Southwest Monsoon 2018 commenced very late on September 28. In fact, Monsoon started retreating at a rapid and pace and at that point it seemed that this would be the quickest withdrawal of Monsoon in the last few years.
In about one week’s time, Monsoon had withdrawn from entire Northwest, East and Central India. Not only this, conditions were looking favourable for the early onset of Northeast Monsoon during the second week of October itself.
However, emergence of Cyclone Titli in Bay of Bengal changed the scenario and withdrawal of Monsoon was halted. However now, weather conditions have once again become favourable for withdrawal of Southwest Monsoon from the entire country and simultaneously for the onset of Northeast Monsoon in the next 24-48 hours.
Unlike Southwest Monsoon, there is no official onset date for Northeast Monsoon. The season sets in one go over the region, while Southwest Monsoon sets in place by place. The arrival of Monsoon is declared with the increase in intensity as well as spread.
However, onset of Northeast Monsoon is never attempted before the withdrawal of Southwest Monsoon from the entire country. Normally, the season sets in around October 20, with an error margin of +/-5 days.
Northeast Monsoon that spans from October to December is major rainfall period for Southern Peninsula, particularly eastern half of the region. Tamil Nadu, Kerala, South Interior Karnataka, Rayalaseema and Coastal Andhra Pradesh are the main beneficiaries.
While Kerala and South Interior Karnataka record around 20% of its annual rainfall during the season, rest of the sub-divisions witness around 50% of its annual rainfall, with parts of coastal Tamil Nadu even recording 70% of rainfall.
Rainfall pattern would also undergo some changes as the rainfall that usually occurs during afternoon and late evening, would now be witnessed during night and early morning hours. However, if there is any system, we can expect rains all along the day.
Image Credit:en.wikipedia.org
Any information taken from here should be credited to skymetweather.com