The southwest monsoon in its last leg, has completed withdrawal from the entire country today. The retreat of monsoon is considered complete when the withdrawal line reaches 15°N over the South Peninsula. The withdrawal line was stuck at Navsari over the South Gujarat coast since 05th October 2024. Simultaneously, the Northeast Monsoon has set in over southeast peninsular India, marking the commencement of the season.
The southwest monsoon withdrawal has been completed within the scheduled dates, without much delay. Last year, the withdrawal was completed on the 18th of October and the northeast monsoon have had commenced on the 21st of October. The onset of the northeast monsoon has been influenced by the persistent low-pressure area over central parts of the South Bay of Bengal. Also, there is a well-marked cyclonic circulation over Southwest BoB. These two features, together, have established easterly streams over Coastal Tamil Nadu and South Coastal Andhra Pradesh. Also, the easterly winds have been prevailing up to a depth of over 5,000 feet. Already, North Tamil Nadu, Puducherry and South Coastal Andhra Pradesh have experienced heavy rainfall in the past 24 hours and the intense weather activity continues over and around the capital city Chennai. There have been incessant heavy rains in this area. These are the essential conditions to announce the arrival of the northeast monsoon.
More heavy rains are likely over Coastal Tamil Nadu, and South Coastal Andhra Pradesh, today and tomorrow. Even, the interiors of Tamil Nadu are likely to have moderate to heavy showers over the next 24 hours. The heavy rainfall belt will shift across parts of Kerala and South interior Karnataka, subsequently. The northeast monsoon season lasts between October, November and December. Five sub-divisions of the South Peninsula get covered under the northeast monsoon, namely: Tamil Nadu, Kerala, South Coastal Andhra Pradesh, Rayalaseema and South Interior Karnataka. The seasonal rainfall is expected to be above normal, this year.