After pounding north Tamil Nadu, remnant of Cyclone Ditwah drifts inland; city to get light rain today

For the third consecutive day, the remnant of cyclone Ditwah continued to pound parts of north Tamil Nadu, particularly Chennai and Tiruvallur districts, on Wednesday (December 3, 2025). The system is likely to weaken into a low-pressure area by Thursday (December 4, 2025).

As the circulation is slowly moving inland, the Regional Meteorological Centre (RMC) has issued a yellow alert for Krishnagiri, Dharmapuri, and four south coastal districts, including Thoothukudi and Kanniyakumari, indicating heavy rainfall on Thursday. Chennai, however, will likely experience only light to moderate showers.

Torrential rain

The system brought rainfall to areas along its path as it drifted inland. Ennore was battered by torrential rain for the third day in a row, recording 15 cm by 6 p.m. on Wednesday (December 3, 2025). The locality had accumulated nearly 56 cm over three days. Various parts of Chennai, including Puzhal (5 cm), Villivakkam (4 cm), and Tiruninravur (3 cm) received moderate to heavy rainfall till 6 p.m. However, south Chennai saw relatively lighter showers.

Other districts, including Tiruchi and Ramanathapuram, also received rain till Wednesday (December 3, 2025) evening.

According to the RMC, the system is likely to drift southwestwards — across north coastal Tamil Nadu and Puducherry — and weaken into a low-pressure area by Thursday (December 4, 2025).

Moreover, a trough runs from the remnant of Cyclone Ditwah over north Tamil Nadu-Puducherry coast to the Lakshadweep area across north interior Tamil Nadu, north Kerala, and south interior Karnataka.

These systems brought sustained rainfall over various districts on Wednesday (December 3, 2025), and are expected to trigger isolated heavy rainfall over parts of the State on Thursday (December 4, 2025).

The system moved slowly over land and triggered rain along its track in the interior regions. Rainfall activity is expected to taper, said P. Senthamarai Kannan, Director, Area Cyclone Warning Centre.

During the 24 hours ending 8.30 a.m. on Wednesday (December 3, 2025), Ennore and the Hindustan University recorded 15 cm of rainfall each, followed by Chetpet in Tiruvannamalai district (13 cm). Many other places in Chennai and districts such as Pudukkottai and Villupuram also received moderate to heavy rainfall.

The persistent rainfall has significantly bridged Chennai’s seasonal deficit, reducing it to 2%.

Water release increased

For the sixth time since the start of the Northeast monsoon, the shutters of the Red Hills reservoir were opened on Wednesday (December 3, 2025). The water discharge was gradually raised to 2,500 cubic feet per second (cusecs) by 5 p.m., as the locality received nearly 6.4 cm of rain by evening.

While the water discharge from the Chembarambakkam and Poondi reservoirs is being maintained at a minimal level, the floodgates of the Red Hills reservoir had to be opened wider as it steadily received an inflow of 5,000 cusecs, to maintain adequate flood buffer space. Storage at Red Hills touched 96% of its capacity.

Officials of the Water Resources Department said the five reservoirs together hold nearly 86% of their storage capacity. Controlled releases are being carried out to maintain sufficient storage without posing a flood risk to downstream areas.

Meanwhile, Chennai Metrowater treated nearly 962.34 million litres of sewage on Wednesday (December 3, 2025), compared to around 700 mld on non-rainy days.