As Tamil Nadu’s monsoon surplus shrinks, all eyes on Andaman sea weather system

Light rainfall may be experienced over coastal parts on October 31 when the weather system moves closer to the Indian region. | Photo Credit: R. RAGU After a brief lull, the Northeast monsoon is likely to gather pace in Tamil Nadu from November 1. All eyes are on a fresh low pressure area over the Andaman sea, which is likely to further intensify, and its possible impact over the State.With Tamil Nadu’s monsoon rainfall surplus shrinking from 58% recorded a few days ago to 37% on Thursday amid a dry spell, expectations are building around the new system and its potential to revive widespread rainfall activity.The weather system, which is currently over the south Andaman sea, is likely to gain strength as a depression over southeast Bay of Bengal, adjoining Andaman and Nicobar islands and Andaman sea by Saturday, according to the Regional Meteorological Centre (RMC).V.R. Durai, Head, Regional Weather Forecast Centre, RMC, said the remnant of the very severe cyclonic storm Arnab is likely to weaken into a well marked low pressure area over Chhattisgarh and adjoining Odisha region by Thursday and gradually dissipate.“The fresh weather system is still far away from Indian region. We are closely monitoring its movement and intensity. There will be more clarity on its track and rainfall impact zone by Friday,” he said.When the system moves close to the Indian region, light rainfall may be experienced over coastal parts on October 31. Warm weather for the past few days may cause wind convergence and trigger moderate rainfall with gusty winds in interior parts such as Tiruchi and Erode, Western Ghats and North coastal districts from November 1.The RMC expects heavy rainfall in isolated places of Coimbatore and Nilgiris districts on November 2 and 3. Moist easterly winds may return from early November as Cyclone Arnab’s influence fades away, he said.Chennai awaits Krishna water supplyWhile October rainfall has led to a marginal rise in storage in Chennai’s reservoirs, the city is awaiting its share of Krishna water, as the Andhra Pradesh reservoirs supplying water to Chennai are yet to receive inflows. The storage in Chennai reservoirs have increased from 34% of their capacity recorded on October 17 to 45% on Thursday.It may be recalled that Chief Minister C. Joseph Vijay visited Andhra Pradesh earlier this month to discuss Krishna water. Officials of the Water Resources Department said the network of water bodies, including Srisailam, Somasila and Kandaleru reservoirs, supplying water to Chennai now have only 25% of their storage and no inflow post Cyclone Arnab.“Andhra Pradesh authorities have assured us that they will be able to resume Krishna water supply once the Kandaleru reservoir receives sufficient inflows this monsoon either from reservoirs upstream or catchment areas. We are monitoring the situation,” said an official. Published - October 29, 2026 07:28 pm IST