Low pressure in the Bay of Bengal brings good rain in Tamil Nadu

The tropical weather systems, beginning with Cyclone Phailin in mid-October and followed by Cyclone Helen and Cyclone Lehar have helped in mitigating some of the deficit rainfall in coastal Andhra Pradesh. Its impact was felt even in south interior Karnataka, Kerala and Marathwada. These regions received excess rain in the last week of November. During this period, from 20^th to 27^th of November, north coastal Andhra Pradesh recorded 66% more than the average rainfall, while Tamil Nadu, which has maximum dependency on the northeast monsoon saw a deficit of about 68%.

Weather models at Skymet indicate that Tamil Nadu has been facing a rain deficit of about 27% from the beginning of the northeast monsoon season, i.e. from the 1^st October till the 4^th of December. The actual average rainfall during this period in the state has been recorded at 269 mm, against the normal average rainfall figure of 369 mm. Further it suggests that Chennai has been facing a rain deficit of about 33% and received only 441 mm of rain till date, against the normal average of 662 mm. The interior parts have been the driest with Tirupur being deficit by 46 %, Madurai by 37 % and Tanjavore by 36 %, till the 4^th of December.

Below is a list of rainfall figures from the 1^st of October to 4^th of December:-

Places	Actual Average Rain (mm)	Normal Average Rain (mm)
Karaikal	460	796
Nagapattinam	530	706
Chennai	441	662
Trichi	232	328

The low pressure in the Bay of Bengal, which had been lingering as a well-marked low pressure area since 5 days in southwest Bay of Bengal, finally turned into a depression today afternoon. The system now lies 500 km away from Chennai and in view of this system, coastal Tamil Nadu has received good amounts of rain from the 1^st to 6^th of December. During this period Karaikal received 233 mm, Nagapattinam 190 mm, Pamban 275 mm and Chennai 67 mm of rain. Rain remained confined to south coastal Tamil Nadu and the interiors received only traces. Nevertheless, we can say that this system came as a blessing for Tamil Nadu.