Northeast monsoon made a mild onset over South Peninsula on 21 October 2023. Unlike decent monsoon bursts at the time of onset, announcing arrival, ingress of winter monsoon was absolutely weak. It hardly made any noise. This dormant spell persisted all through the remaining days of October, leaving large Pan India rainfall deficiency of 32%. With the latest developments, hopes getting rekindled for an uptick of weather activity over large pockets of South India.
The onset week between 19th and 25th October remained nearly dry over most sub divisions, other than Kerala, over South Peninsula. This week had registered only 2mm of rainfall against the weekly average of 14mm, leaving a deficiency of 86%. The following week between 26thOct and 01stNov, was also no better, except for some parts of Tamil Nadu and Kerala. Tamil Nadu recorded 22.9mm rainfall against the weekly normal of 49.1mm, leaving deficiency of 53%. State of Kerala was shade better with respective figures of 43.5mm and 62.5mm with a deficiency of 30%. Overall, this week recorded rainfall of 2.6mm against normal of 10mm. Seasonal Pan India deficiency was retained at 33%.
Four out of five sub divisions of Northeast monsoon have significantly reduced rainfall in the month of November. State of Tamil Nadu has an average of 181.9mm rainfall during November as against 172mm in October. Kerala drops to half of what is received in October. Normal rainfall in November stands at 153.1m as against the average of 306.4mm in October. Pan India rainfall also reduces sharply in November (29.7mm) from its reasonable mark of 75.4mm in October.
There is a well marked trough in the easterlies over southwest Bay of Bengal, off Tamil Nadu coast. Also, a cyclonic circulation is lying over Sri Lanka and Gulf of Mannar. Under the influence of these weather systems, fairly wide spread rain and thundershowers with moderate intensity are likely over the entire regime of northeast monsoon. This activity may last for the next one week. Isolated places can expect heavy downpour as well.