the north eastern winter monsoon winds cause rainfall along
Monsoon While travelling towards the Indian Ocean, the dry cold wind picks up some moisture from the Bay of Bengal and pours it over peninsular Indi] and parts of Sri Lanka. Cities like Chennai, which get less rain from the Southwest Monsoon, receive rain from this Monsoon. About 50% to 60% of the rain received by the state of Tamil Nadu is from the Northeast Monsoon.[36] In Southern Asia, the northeastern monsoons take place from December to early March when the surface high-pressure system is strongest.[37] The jet stream in this region splits into the southern subtropical jet and the polar jet. The subtropical flow directs northeasterly winds to blow across southern Asia, creating dry air streams which produce clear skies over India. Meanwhile, a low pressure system develops over South-East Asia and Australasia and winds are directed toward Australia known as a monsoon trough.
Climate of Tamil Nadu The state has three distinct periods of rainfall: advance rainfall ; rainfall from the tropical cyclones emerging in the neighbourhood of the Andaman islands during the Retreat of Monsoons(October–November); and the North East monsoon during the months of October–December, with dominant northeast monsoon winds from the western disturbances emerging over the Mediterranean Sea. The dry season is from February to early June.