Chennai, Nov 10 (IANS): The Indian Meteorological Department (IMD) has issued an orange alert for Chennai, Kancheepuram, Tiruvallur, and Chengalpattu districts on November 11 and 12.

This follows a heavy to very high rainfall alert in these districts. In a statement, the

IMD said that the weather system is likely to move towards Tamil Nadu and Puducherry and this may cause heavy to very heavy rainfall, especially in Chennai and adjoining districts.

"Under the influence of a cyclonic circulation over Southwest Bay of Bengal and adjoining equatorial Indian ocean, a low-pressure area has formed over the same region and the cyclonic circulation extends up to 7.6 km above sea level," the statement read.

The weather department said that the cyclonic circulation is likely to be more prominent in the next 48 hours and likely to move northwestwards bringing in heavy to very heavy rains.

According to IMD, Tamil Nadu has received 237.7 mm of rainfall since October 1 and is in deficit while Chennai district received 459.4 mm during the same period with a 13 per cent increase in rains.

The IMD has forecast thunderstorms and lighting over Chennai and adjoining districts in the next 48 hours.