Northeast Monsoon continues to remain active with most parts of Tamil Nadu coming under rains yesterday. Crucially some of the west interior TN areas which were missing out also got light to moderate rains. The IMD observatory at Cuddalore recorded 11 cms of rains while the observatory at Pondicherry recorded 6 cms of rains as Cuddalore, Villuppuram dts along with Pondicherry saw some of the heaviest spell of rains yesterday. Chennai & suburbs after a fairly clear weather during the early part of the day started seeing on & off spell of rains later in the afternoon which continued until the early morning hours.
Though it could be said the heavier spell of rains which were expected for Chennai eventually ended up over South Coastal Andhra Pradesh most parts of Chennai & Suburbs did get moderate rains at the end of the day. With daily rains for the past 5 day or so & expected to continue for another couple of days at the least this is good for the water table in terms of percolation & rainwater harvesting rather than one extreme spell of rains that trigger a lot of run off followed by dry few days.
It is an understatement to say the near stationary position of the Low Pressure Area over the Comorin Sea is the reason for this sustained spell of rains over not only Tamil Nadu but also Coastal AP & Kerala as well. The LPA has been pretty much in the same region for the past few days & that is likely to take a toll on the overall structure of the circulation which is now showing signs of elongation. This disorganized structure is likely to reduce the strength of the circulation & unless it moves NW into Arabian Sea, which models expect it to do today / tomorrow, it may not be able to get its structure again.
In the context how things are happening, there has been a delay of 12 to 24 hours on what the models have been estimating & how events have happened in real time conditions we need to see when this eventual NW movement of the LPA into Arabian Sea happens. As things stand we can expect another day of fairly widespread rains over Tamil Nadu with heavy rains likely in a few places over South TN.
Chennai & suburbs along with rest of North Coastal TN may see intermittent spells of light to moderate rains with heavier spell of rains likely to happen during the late night / early morning hours. But keep a watch on Radar / Satellite images for sudden burst of heavy rains.