Tamil Nadu rain update: Showers likely in 25 districts, heavier spells predicted in Western areas over next 2 days; see why

Tamil Nadu is set to receive a good deal of rainfall over the next two days, with the India Meteorological Department (IMD) on Sunday predicting light to moderate rainfall in most parts of the state, and heavier spells in select Western districts.

This is mainly influenced by a fresh low-pressure area forming over the North-west and adjoining West-central Bay of Bengal, near the Odisha-Andhra Pradesh coast.

The low-pressure system, which pulls moist southwesterly winds from the Arabian Sea, is expected to sustain widespread rainfall across the state, with heavier activity confined to the Western hill districts.

As many as 16 districts across Tamil Nadu are set to receive light to moderate rainfall, including Chennai, Kanchipuram, Tiruvallur, Ranipet, Vellore, Nilgiris, Coimbatore, Theni, Tirunelveli and Kanyakumari. 9 other districts are expected to receive light rainfall, including Cuddalore, Tiruchirappalli, Thanjavur, Nagapattinam, Pudukkottai, Puducherry and Karaikal.

On Monday and Tuesday, light to moderate showers accompanied by thunderstorms and lightning were predicted for most parts of Tamil Nadu: including Puducherry and Karaikal.

The IMD has also highlighted the Nilgiris and the Ghat sections of Coimbatore for heavy to very heavy rainfall. Theni is also likely to get isolated heavy spells on Monday.

These districts are particularly vulnerable as orographic lifting along the Western Ghats amplifies the moisture inflow linked to the low-pressure system.

Orographic lift—or the upward movement of warm, moisture-rich air, which cools rapidly at higher altitudes—has been linked to cloudbursts in hilly regions, such as Kishtwar and Uttarkashi.  

Gusty winds reaching 40–50km/h are also predicted across parts of Tamil Nadu on August 17–18.

While Chennai and its suburbs are expected to see one or two spells of light to moderate rain with thunderstorms, the IMD notes that the capital’s rainfall will be modest compared to that in the Western hills.

Since June, Tamil Nadu has recorded an overall 15 per cent surplus in seasonal rainfall. With the low-pressure system set to move inland, rainfall in the Southern parts of the state is expected to reduce after August 19, although the Nilgiris and adjoining areas remain on alert.

Authorities have cautioned residents in vulnerable hilly zones to remain prepared for landslides, swollen streams and flash floods during intense spells this season.

The IMD has also warned fishermen against venturing into the Bay of Bengal between August 18 and 20. 

India