Chennai, Nov 19 : After a lull for a few days, Chennai and other districts are expected to receive heavy to very heavy rainfall in the coming days from Monday onwards. The heavy rain, according to the Indian Meteorological Department (IMD) will be due to a slow-moving weather system over the Bay of Bengal. Weather department in the statement said that on November 21 and November 22, rainfall could be extremely heavy and possibilities are there for 20 cm rainfall on these days in some districts. Heavy rains are also expected at one or two places in Chengalpattu, Cuddalore, and Villupuram districts on Sunday. The IMD also said that heavy rains are expected in Chennai, Myladuthurai, Cuddalore, Perambalur, and Chengalpattu districts of Tamil Nadu on November 21. The weather department also predicted that the rainfall area may change after Tuesday based on the movement of the weather system over the Bay of Bengal. National Disaster Response Force (NDRF) volunteers and State Disaster Response Force (SDRF) volunteers have sounded an alert on the heavy to extremely heavy rains expected on November 21 and November 22. However, the IMD officials said that the low-intensity weather system may not reach the next stage of intensification like the deep depression. /IANS