The North-East monsoon could announce its arrival over Tamil Nadu in a deceptively subtle fashion, not with a well-defined storm spinning over the Bay of Bengal, but with an elongated trough in the easterlies that may organise clouds and trigger rain gradually over the larger South Peninsula as well.
The takeaway is Chennai should watch not merely for a darkening sky or a sudden wind shift, but for persistent easterlies (winds blowing from the east), growing cloud bands and organised rain-bearing convection (cloud building process). A trough may lack the unmistakable signature of a rotating storm, yet still deliver substantial rain, and potentially signal the seasonal transition towards the North-East monsoon.
The India Meteorological Department (IMD), in its latest update reiterated conditions were becoming favourable for the South-West monsoon to withdraw from the remaining parts of the country and for the North-East monsoon rains to commence simultaneously. The withdrawal line continued to extend from East India into Peninsular India, passing through Kolkata, Angul, Khammam and Honavar.
