Even as the southwest monsoon lingers on, the Indian Meteorological Department (IMD) has said that the northeast monsoon is all set to make an onset over southern peninsular India on October 17.
With the withdrawal of the southwest monsoon severely delayed, this means that the southern peninsula will have little respite from rainfall activity. The southwest monsoon has not fully withdrawn from parts in the central, east and western regions of the country so far.
With IMD issuing forecasts suggesting of heavy to very heavy rain over most parts of Tamil Nadu, Pudducherry, Karaikal, north interior Karnataka, Kerala and Mahe till the middle of this week, atmospheric conditions are becoming favourable for the commencement of the northeast monsoon, also known as winter monsoon.
Surplus rainfall for southern states
This year, during the June-September period, Karnataka (18 per cent), Pudducherry (15 per cent), Kerala (5 per cent),Tamil Nadu (1 per cent) recorded surplus rainfall. As a result, these states are in a comfortable position with respect to their water requirements even before the commencement of the northeast monsoon. With both the Arabian Sea and Bay of Bengal remaining warmer than usual in this post-monsoon period, the upcoming season is expected to cause storms, which in turn could cause above normal rain to the southern states. However, the concern is how much more rain can these areas withstand.
Generally, IMD declares the onset of the northeast monsoon when the the southwest monsoon has withdrawn completely till parts of north Karnataka, Telangana and Odhisha and is prevailing only over parts of Tamil Nadu, Kerala, Lakshadweep and Andaman and Nicobar islands. Since the withdrawal generally does not happen before October 15, the onset of the subsequent monsoon is not attempted prior to that. Even though the delayed exit of the southwest monsoon has not interfered with the onset of northeast monsoon so far, rainfall activity shall continue over the southern states, IMD officials, noted.
The northeast monsoon is crucial for Tamil Nadu, which receives 70 per cent of its annual rainfall in the October-December period.
Major dams in Tamil Nadu, Andhra Pradesh and Telangana are already stocking buffer reserves owing to excess rain. At the end of September, reservoir-wise water stocks stood at: Andhra Pradesh (127 per cent), Tamil Nadu (70 per cent), Karnataka (22 per cent), Telangana (11 per cent) and Kerala (6 per cent).