This is expected to be triggered by a cyclonic circulation near the Sumatra coast and the adjoining South Andaman Sea. As a result, heavy rainfall is anticipated in the southern states of Tamil Nadu and Andhra Pradesh in the coming days.

The IMD said that the system will likely move west-northwestwards and strengthen into a depression over the central parts of the south Bay of Bengal within the next two days.

Additionally, a cyclonic circulation has been observed over the Comorin area and its surrounding regions at lower tropospheric levels, according to the IMD.

IMD’s rain prediction

In its latest bulletin, the weather department has predicted light to moderate rainfall at a few places, accompanied by isolated thunderstorms and lightning over Lakshadweep on November 21, and over Tamil Nadu, Puducherry, and Karaikal on November 21 and 25. Kerala and Mahe are expected to experience similar conditions on November 25.

The Andaman and Nicobar Islands will see light to moderate rainfall at many places throughout the week. Assam, Meghalaya, and the northeastern states of Nagaland, Manipur, Mizoram, and Tripura are likely to experience light to moderate rainfall at isolated locations on November 21 and 22.

Isolated very heavy rainfall is expected over south Tamil Nadu on November 21 and 26, as well as over Coastal Andhra Pradesh and Yanam on November 26 and 27.

Heavy rainfall is also likely over Nicobar between November 21 and 24, and in Kerala and Mahe on November 21, 26, and 27.

Other regions, such as south Tamil Nadu on November 25 and 27 and Rayalaseema on November 26 and 27, may also experience isolated heavy rainfall.

Heavy rain in Tamil Nadu

Heavy rains continued to affect parts of Tamil Nadu on Thursday, leading to severe flooding and waterlogging in residential areas. In Thoothukudi, urban areas like Rajagopal Nagar, Pushpa Nagar, Raju Nagar, Postal Telegram Colony, and other parts of the city have experienced significant waterlogging. Visuals from the area showed houses submerged in rainwater.

Since the northeast monsoon began in October, it has brought widespread rainfall to the northern and delta regions of Tamil Nadu, including Chennai, Chengalpattu, and Kanchipuram.

Delta districts such as Thanjavur, Nagapattinam, Tiruvarur, and Mayiladuthurai have been heavily impacted, with waterlogged roads and disruptions to daily life.

The weather department has forecast continued rainfall, accompanied by thunderstorms and lightning, across several regions in the coming days.