Talking to reporters here, Deputy Director General of Meteorology S Balachandran said the north-easterly winds that act as a precursor to the monsoon might set in around October 26 or 27 and set the stage for the onset of northeast monsoon over the State, South Andhra, Rayalaseema and South Karnataka. He said while the monsoon would be near normal in north Tamil Nadu districts, it would be below normal in southern districts.

The Met office said that with the setting in of north-easterly winds in the lower tropospheric levels over the Bay of Bengal, the southwest monsoon was expected to withdraw from the country around October 28 paving the way for the onset of the northeast monsoon. Attributing the heavy rain in Chennai and other neighbouring districts on Thursday to the depression over west-central Bay of Bengal and the convective activity that resulted in the thunderstorms in some parts of the State, the Met office said Pallipattu in Tiruvallur district received a maximum of 17 cm of rain during the last 24 hours.