The erstwhile cyclone seen hastening the onset early by almost a week
Private forecaster Skymet Weather has predicted that the onset of South-West monsoon over Kerala will likely occur on May 26, six days in advance of the normal June 1 timeline, with a model error of +/- three days.
Earlier on Thursday, India Meteorological Department (IMD) had indicated that the monsoon may enter the South Andaman Sea, the farthest outpost in the territorial waters, by May 15 (Sunday), which too is early by a week. The IMD is expected to come out with its own assessment of a likely onset dynamics for Kerala soon.
‘Asani’ enables process
Skymet said in its outlook statement that the onset process is chiefly controlled by the oceanic conditions, both in the Arabian Sea and the Bay of Bengal. Recent cyclone ‘Asani’ enabled the monsoon stream to lock in over the Bay, earlier than normal. Also, the remnant of this storm, as a depression over Peninsular India, has been instrumental in initiating the cross-equatorial monsoon flow.
Normal monsoon outlook
The combined influence has scared away the obstructing presence of a seasonal anti-cyclone from over the central parts of the Arabian Sea, an essential condition for ingress of the monsoon flows . This will also be assisted by an MJO (Madden Julian Oscillation) wave entering the Indian Ocean, albeit with low amplitude. Pre-monsoon showers will be extensive and powerful over Kerala, Skymet said.
Earlier, Skymet had said in its outlook that the June-September monsoon would be ‘normal’ to the tune of 98 per cent (with an error margin of +/-5 per cent) of the long period average (LPA), while the IMD predicted 99 per cent. This would make 2022 the fourth consecutive year of normal or above-normal monsoon.