The Bay Depression that has been keeping every Chennai citizen is now lying around 120 kms to the Southeast of Chennai and is making a slow movement in a Northwest direction. After starting the day slightly to the Northeast of Sri Lankan coast during the day the Well Marked Low Pressue intensified into a depression and now lies roughly to the east of Pondicherry.
As one can observe in the above image the Bay Depression now lies off the coast of North Tamil Nadu. There is consensus among models about the Bay Depression moving in a N/NW direction towards Chennai over the course of next 12 hours or so. In the meanwhile it is expected to intensify into a Deep Depression and make a recurve into N/NE direction. As is the case during recurve scenario there is going to be quasi stationary movement with pretty much extreme slow progress made by the disturbance resulting in potentially heavy rains over a short period of time.
As one cane see from the Model forecast for the next 24 hours or so, the Bay Depression is pretty much hugging the Chennai coast for almost 18 hours before it starts its recurve journey towards Andhra Pradesh in a more N/NE direction. This quasti stationary time period is the one that is likely to provide heavy rains to parts of North Coastal Tamil Nadu & Coastal Andhra Pradesh with few places expected to receive extremely heavy rains. It is extremely difficult to judge the exact point of recurve and the time taken but keeping in mind being alert is the paramount need now we are going ahead with a conservative time span for the expected recurve of the Bay Depression.