Chennai/IBNS: Heavy rainfall has been forecast in Tamil Nadu besides cyclonic winds of around 85 km an hour as Cyclone Mandous started beginning its landfall, the weather office predicted Friday.

The cyclone will make landfall around midnight near Mamallapuram in Tamil Nadu, which is between Puducherry and Sriharikota, with a wind speed of 70 km an hour, said officials.

Heavy rainfall has already begun as the cyclone is passing over the Chennai coast around midnight.

Ahead of the landfall, 16 flights were cancelled at the Chennai airport due to bad weather Friday including three international flights.

"Passengers are requested to check with the concerned airline(s) for further updates," tweeted Chennai International Airport.

Even as the intensity of the cyclone has lessened, three districts are on red alert including Chengalpattu and Kancheepuram which border the capital Chennai, and Villupuram just south of them.

Schools and colleges have been shut down in 12 districts of the state, including Chennai.

On the intensity scale, Cyclone Mandous was classified as 'Severe Cyclonic Storm', the fourth highest, meaning winds of 89-117 km per hour, but it has since come down to 'Cyclonic Storm' with winds at 62-88 km/hour.

The most extreme is a 'Super Cyclonic Storm', with winds at 222 km an hour and more.

A storm warning flag has been hoisted at the Puducherry port and fisherfolk have been asked not to venture into the sea.

The National Disaster Response Force (NDRF) has been kept on standby in Chennai.

The Greater Chennai Corporation has ordered the closure of all parks and playgrounds.

Equipment like boats, high-voltage motors, sucker machines and cutters have been kept ready for rescue operations as the cyclone might gather more intensity.

Alert has been also sounded in neighbouring Andhra Pradesh.

"It would continue to move west-northwestwards and cross north Tamil Nadu, Puducherry and adjoining south Andhra Pradesh coasts between Puducherry and Sriharikota around Mahabalipuram... during midnight of today, the 9th December to early hours of 10th December," the statement by India Meteorological Department read.

"It would continue to move west-northwestwards and cross north Tamil Nadu, Puducherry and adjoining south Andhra Pradesh coasts between Puducherry and Sriharikota around Mahabalipuram... during midnight of today, the 9th December to early hours of 10th December," the statement by India Meteorological Department read.

The cyclone was named by the United Arab Emirates (UAE) as a member of the World Meteorological Organisation (WMO). In Arabic, it means "treasure box" and is pronounced as "Man-Dous"