The upcoming rains can be attributed to a trough which is seen extending along the equator up to Comorin region. The system is likely to strengthen the northwesterly winds over Coastal Tamil Nadu, leading to increase in levels of moisture.
In wake of this, weather has already gone cloudy to partly cloudy over most parts of coastal Tamil Nadu. We can also expect drizzling during the late night hours.
Thereafter, we can expect light rains over Coastal Tamil Nadu including Chennai during the next 24 to 48 hours.
The trough will also impact the weather over Andaman and Nicobar, wherein rains will intensify with some isolated heavy falls.
Though December has ended with surplus rainfall, Chennai is still battling with deficit rainfall. During this month, the city has recorded 335.8 mm of rain against its monthly mean of 191 mm. These rains were due to back to back two cyclones – Nada and Vardah.
However, October and November were highly rain deficit. Chennai records more than 60% of its annual rainfall in November. However, this year saw mere 50 mm of rain as compared to its monthly rainfall of 407 mm.
Image credit: The Hindu
Any information taken from here should be attributed to skymetweather.com