The city is likely to end the rainy season this year with a deficit. It has received 61 cm of rain so far against a normal of 73 cm during the northeast monsoon, a shortfall of 17%.
The weather station at Nungambakkam has received 57.4 cm of rainfall against its seasonal average of 83 cm, a shortfall of nearly 30%. Despite the deficit in the northeast monsoon, Nungambakkam has managed to record 107 cm of annual rainfall against a normal of 140 cm.
This was possible because of a good southwest monsoon between June and September, note weather bloggers. Nungambakkam recorded 49 cm of rain against its average of 45 cm. This helped arrest the fast depleting water table.
J. Saiprasath, who blogs with Kea Weather and Chennaiyil Oru Mazhaikalam, said this year, the absence of cyclones during the northeast monsoon was one of the reasons for uneven distribution of rainfall over the city. Areas in west, northwest and south have received more rain than central and north Chennai this year. Citing past years, he said the southwest monsoon had performed better in Chennai since 2010 and helped bridged the deficit during some years. In 2010, Chennai had already received 80 cm during summer before the onset of the northeast monsoon. “There is an increasing trend in average southwest monsoon rainfall over the city in the past decade,” he added.
Rain elsewhere
Several districts other than Chennai and its neighbourhood may experience light to moderate rains till Christmas. One or two places in a few districts in south coastal Tamil Nadu have may experience heavy rainfall on Tuesday.
A cyclonic circulation that lies over south Tamil Nadu and neighbourhood would bring rainfall over the State. However, officials of the Meteorological Department said that in districts such as Chennai, Kancheepuram, Tiruvallur and Krishnagiri the chance of rain is low.
N. Puviarasan, director, Area Cyclone Warning Centre, said Chennai may experience cloudy weather and a maximum temperature of 30 degrees Celsius.
The State has already exceeded its average rainfall for the northeast monsoon season. It has recorded 45 cm against its average of 43.4 cm so far since October 1. “Rainfall that the State gets during the last days of the year will act as bonus. The deficit in rainfall in districts like Chennai may reduce by a few centimetres. We expect the monsoon to spill over to early January,” Mr. Puviarasan added.
