Chennai is gearing up for another bout of intense rain as a developing weather system over the Bay of Bengal strengthens and edges closer to becoming Cyclone Senyar. The Indian Meteorological Department (IMD) has placed the city on orange alert for November 29, signalling the likelihood of heavy to very heavy rainfall.

The low-pressure area currently lies over the Comorin region and southwest Bay of Bengal near Sri Lanka. It is expected to evolve into a depression by November 27 and may intensify further as it moves north-northwest towards the Tamil Nadu coast.

Shift from earlier system; new threat takes centre stage

Meteorologists have now shifted their attention from a previous system near the Strait of Malacca, which they say is weakening and unlikely to impact Tamil Nadu. Instead, the developing circulation closer to Sri Lanka holds greater potential for intensification, placing Chennai and its neighbouring districts at risk of widespread rainfall.

What to expect: Orange alert on Nov 29, Yellow alert on Nov 30

According to the IMD, coastal districts from Tiruvallur to Ramanathapuram are likely to experience intense downpours on November 29. Chennai is expected to record between 6 and 12 cm of rain on November 30 under a yellow alert.

Delta districts may witness heavier spells a day earlier, on November 28, as the outer rainbands of the system tighten and approach the coast.

Mahesh Palawat, meteorologist at The Weather Channel, noted that while "extreme" rainfall may not hit the city, the alerts act as an important precaution as the system's track and strength continue to evolve.

Rain may bring familiar worries: flooding, slow traffic and power cuts

With many parts of the city already prone to flooding, officials have warned residents to brace for disruptions even if rainfall is moderate. Water stagnation and drain overflow remain major concerns, particularly in neighbourhoods with poor drainage.

Traffic delays are likely at several hotspots that routinely flood during heavy rain - T. Nagar, Guindy junction, Velachery main road, Kodambakkam bridge, GST Road, Madhavaram, the Adyar river stretch, Perambur bridge and the Koyambedu bus corridor. Motorists may face diversions and are advised to avoid subways and start early.

Both the Greater Chennai Corporation and TANGEDCO are considering precautionary feeder shutdowns in low-lying areas to prevent electrocution risks, which may result in intermittent power supply in localities such as Pallikaranai, Mogappair, KK Nagar and parts of North Chennai.

Elsewhere in Tamil Nadu, flooding already taking a toll

Even before the formation of Cyclone Senyar, Tamil Nadu has begun to feel the strain of the ongoing weather systems. A deep depression over the Bay of Bengal flooded over 300 acres of paddy fields in Thanjavur district on Tuesday. In Thoothukudi, electric pumps were deployed to clear waterlogged residential pockets.

'Rain may shift towards coast,' says weather blogger

Weather blogger Pradeep John said rainfall may reduce over interior Tamil Nadu once the new system consolidates, with heavier spells likely to concentrate closer to Sri Lanka and the coastal stretch.

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