“Not many countries get rainfall in December. It is biting winter or summer depending upon the continent in which you live. But it is only Tamil Nadu which receives rainfall and this year Chennai and nearby districts have received record rainfall,” said Skymet Weather chief meteorologist Mahesh Palawat.
Beyond Chennai, California and Caribbean islands are the ones which receive rainfall in December, but the intensity is less than what Chennai has experienced since the start of the month this year.
Chennai city is breaking all records with regard to rain at the end of 2015. In November, the city received record rain of 117.8cm which is higher than 108.8cm recorded in 1918. But on December 2, the city’s Nungambakkam observatory recorded 29.4cm of rainfall and Meenambakkam recorded 34.5cm of rainfall.
Chennai once again broke the record rainfall on a single day in December. According to Met department website, it was in 1901 when Chennai city recorded 261.10mm on December 10 but it has crossed that record on Tuesday. This comes after the city crossed its record rainfall set in 1918.
“This year the low pressure and troughs in the Bay of Bengal formed in south Andaman compared to central Bay last north-east monsoon. Due to this the systems in Bay moved in north-easterly direction and stationed in northern districts of Tamil Nadu bringing in more rainfall to Chennai, Kancheepuram and Tiruvallur,” said Palawat.
The basic reason for excess rainfall is El Nino. “Many typhoons were formed in the Pacific Ocean this year due to the warming of the ocean. But the Indian Ocean is cool compared to the Pacific and the wind carried more moisture bringing in extreme rainfall,” said Palawat.
In 2013, south-west of United Kingdom received record rainfall during December following a low pressure. The area received 163mm of rainfall which was the highest since 1978. But Chennai city received even more rain this season in December.