Second Bay of Bengal system due on Friday as Tamil Nadu braces for rain till 26 October

Tamil Nadu is in for several more days of heavy rain, with one low-pressure area already over the Bay of Bengal and a second expected to take shape from Friday that forecasters say could strengthen into a cyclone.

A fresh low-pressure area formed over the southwest Bay of Bengal, off the Tamil Nadu coast, on Wednesday. Another system is likely to form around 23 October and has the potential to intensify into a cyclone. Heavy to very heavy showers are expected to continue across the state until 26 October, including the Cauvery delta districts that feed much of the state’s paddy crop.

The Regional Meteorological Centre in Chennai has warned of heavy to very heavy rain at isolated places in Chennai, Thiruvallur, Chengalpattu, Cuddalore, Villupuram, Thanjavur, Thiruvarur, Nagapattinam, Mayiladuthurai and Ramanathapuram, as well as Puducherry and Karaikal. In the far south, Tirunelveli and Thoothukudi were reported to be under an orange alert for up to 20 cm of rain on Wednesday and Thursday.

A wet week for Chennai

Chennai and its neighbouring districts have been under the northeast monsoon’s first heavy spell since the weekend. Schools in Chennai, Tiruvallur, Chengalpattu and Kancheepuram were shut on Wednesday, and district collectors will decide on further holidays as the rain develops.

Pradeep John, a member of the Tamil Nadu government’s El Nino expert group, said the city would get some respite during the day before the next band moved in. “Rainfall is expected to decrease across Chennai during the day,” he said on Wednesday. “Moderate to heavy rain is likely tonight and early in the morning.”

The state government has put its disaster machinery on alert and ordered precautionary measures in the districts. The Greater Chennai Corporation says it has repaired 4,691 potholes across its 15 zones before the monsoon.

Odisha and Andhra watch the track

The second system is being watched closely further up the coast. Some international weather models project that a low formed around 23 October could become a depression by about 27 October and move towards the central Bay of Bengal, with a possible cyclone crossing between north coastal Andhra Pradesh and southern Odisha by the end of the month.

The India Meteorological Department has not forecast a cyclone so far, and the track and strength of any system remain uncertain. Coastal Andhra Pradesh is expected to see isolated heavy rain over the next three days, with light to moderate rain and thunderstorms elsewhere in the state.

The next IMD bulletins, due on Thursday, should show whether the first low has deepened and how quickly the second is taking shape.