IMD issues orange alert for Chennai, rainfall to continue in southern India until Nov 23

After heavy rainfall reported over Tamil Nadu and Puducherry almost everyday during last week from November 11 to 18, the depression over southwest Bay of Bengal off north Tamil Nadu coast moved west-northwestwards at a speed of 18 kmph during the past 6 hours and lay centred at 5:30 p.m. on November 18, informed the India Metereological Department. 

The IMD further informed that the depression is now very likely to continue to move west–northwestwards and cross north Tamilnadu and adjoining south Andhra Pradesh coasts between Puducherry and Chennai by early morning on November 19 and then move west-southwestwards away from west coast of India and become more marked during the next 48 hours. 

Rainfall is likely going to continue over Tamil Nadu, Puducherry and Karaikal from November 18 to 23. Heavy rainfall is also being predicted over south coastal Andhra Pradesh and south interior Karnataka on November 18 and 19, and over Kerala and Mahe from November 18 to 23.

Thunderstorm nowcast for Tamil Nadu & Puducherry 

A thunderstrom with moderate rain is likely to occur at Puducherry and a few places over Coinbatore, Nilgiris, Erode, Salem, Dharmapuri, Krishnagiri, Thirupattur, Vellore, Ranipettai, Kallakurichi, Villupuram, Cuddalore,Thiruvannamalai, Tiruvallur, Kancheepuram, Chennai and Chengalpattu districts of Tamil Nadu within the next three hours, informed the Regional Meteorological Centre, Chennai.

Meanwhile, the red alert given for Chennai has now been withdrawn by IMD. Orange alert has now been issued for Chennai and its neighbouring districts.The depression is expected to cross Chennai and Puducherry early in the morning on Friday, November 19. Wind speed could be between 40-50 km/hr.

What is causing heavy rains in the southern region? 

In an exclusive conversation with Republic Media Network, the RMC Chennai director explained that low pressure has been forming on both sides of the Southern Peninsula, resulting in heavy rains.

Pointing out at the map, the director described, "See low pressure is there in the South of Bay of Bengal, and it is likely to move westwards. On the other side, low pressure is forming at East Central Arabian sea. So low pressure is on both and since Southern peninsula is in the middle, it is receiving heavy rains."