As many as 39 regions in southern Tamil Nadu witnessed extremely heavy rainfall, the India Meteorological Department said on Monday.

Heavy to extremely heavy rainfall was recorded in Thoothukudi, Tirunelveli, Tenkasi and Kanyakumari districts and light to moderate rainfall at most places in southern Tamil Nadu, the IMD said in a bulletin.

It is for the 24-hour duration commencing 8.30 am on December 17 and ending at 8.30 am, the following day. The rainfall is due to the influence of an upper air cyclonic circulation extending upto the mid-tropospheric levels over the Comorin area and neighbourhood.

Heavy to very heavy rain was recorded at isolated places in Theni, Virudhunagar, Sivaganga and Ramanathapuram districts and isolated heavy rain in Madurai district.

There were 39 extremely heavy rainfall reports, 33 very heavy rainfall reports and 12 heavy rainfall reports from such southern regions. Kayalpattinam in Thoothukudi district reported 95 cm, followed by Tiruchendur and Srivaikuntam (both in Thoothukudi district) reporting 69 cm and 62 cm respectively.

The upper air cyclonic circulation over the Comorin area and neighbourhood extending up to mid tropospheric levels persists.

Rainfall over and above 21 cm is graded as extremely heavy. Between 12 and 20 cm, it is very heavy and from 7 to 11 cm heavy. The classification is based on accumulated rainfall for a 24-hour duration (cm/day).

On December 19, heavy rain is likely at one or two places in Kanyakumari, Tirunelveli, Thoothukudi and Tenkasi districts.

Except for the headline, this story has not been edited by The Telegraph Online staff and has been published from a syndicated feed.