Chennai:  A low-pressure area developing over the Bay of Bengal is expected to intensify into a cyclonic storm by the morning of October 27, the India Meteorological Department (IMD) said on Friday, warning of heavy rainfall in several parts of Tamil Nadu over the next few days.

Chief Minister M K Stalin and Deputy Chief Minister Udhayanidhi Stalin are closely monitoring the situation and have directed senior Greater Chennai Corporation (GCC) officials to implement precautionary measures to mitigate flooding and ensure public safety.

According to the IMD, the low-pressure system currently lies over the southeast Bay of Bengal and is “likely to move west-northwestwards, intensify into a depression over the southeast and adjoining central Bay of Bengal by October 25, further into a deep depression by October 26, and into a cyclonic storm over the southwest and adjoining west-central Bay of Bengal by the morning of October 27.”

Rainfall, thunderstorms expected in Tamil Nadu, Kerala

With the northeast monsoon now active, Tamil Nadu is set to experience widespread rainfall. Several regions have already recorded significant showers in the past 24 hours — Pallipattu in Tiruvallur district received 15 cm of rain, followed by Nalumukku in Tirunelveli with 12 cm. Sriperumbudur in Kancheepuram district recorded the lowest at 1 cm.

Light to moderate rain, accompanied by thunderstorms and lightning, is expected across Tamil Nadu, Puducherry, and Karaikal until October 28, with heavy rainfall likely at isolated locations in Cuddalore, Villupuram, and Chengalpattu districts, as well as neighbouring Puducherry, the IMD said.

For Chennai and nearby districts, the sky will remain partly cloudy with maximum temperatures around 29°C and minimum temperatures between 24°C and 25°C. “One or two spells of light to moderate rain accompanied by thunderstorms and lightning are likely over the next 24 to 48 hours,” the IMD stated.

Kerala is also likely to receive rainfall in the coming days. There is a possibility of light to moderate rain or thunderstorms across Kerala over the next five days. According to the India Meteorological Department (IMD), isolated very heavy rainfall is likely today (October 24), while isolated heavy rainfall is expected between October 24 and 28. 

Meanwhile, a yellow alert has been issued for Kasaragod and Kannur districts on Saturday. Similarly, Kozhikode, Wayanad, Kannur, and Kasaragod will remain under a yellow alert on Sunday, according to the IMD.

Cyclone ‘Montha’ preparations underway

The cyclone — reportedly to be named ‘Montha’, a name suggested by Thailand under the international naming convention — has prompted authorities to activate precautionary and relief measures across coastal districts.

“As the northeast monsoon has become active over Tamil Nadu, bringing widespread rain, the Chief Minister reviewed preparedness measures to tackle the monsoon and directed officials to ensure that rainwater does not stagnate in low-lying areas,” the GCC said in a release.

The CM is reviewing the situation through video conferences with senior officials, including police and disaster management departments, and has instructed the civic body to take all necessary steps to ensure public safety, the statement added.

Relief measures and safety advisory

The Greater Chennai Corporation has readied 1,436 motor pumps, 150 high-capacity (100 HP) pumps, 500 tractor-mounted pumps, 478 vehicles and machines, and 457 tree-cutting units for emergency operations.

Relief camps have been set up at 215 locations, while 106 community kitchens are on standby to provide food and essential supplies. A total of 24,149 personnel, including corporation staff and disaster response teams, have been deployed for relief and rescue operations. About 103 boats, including 36 owned by the GCC, are on standby for potential evacuations.

The IMD has advised fishermen not to venture into the sea until October 28, urging those already at sea to return by Saturday evening as the sea conditions are expected to worsen with the system’s intensification.