Light to Moderate Rains likely over parts of Coastal TN

Weather Update
Reading Time: 2 minutes

As we often mention while Easterlies at times continue well into April, the rains do not happen always unless they are accompanied by an instability along with it. These instabilities could be range from the simple Upper Air Cyclonic Circulation to the complex Easterly / Westerly interaciton due to the effect of Mid Latitude Trough dipping up to Peninsular India. Occasionally these interactions have resulted in sudden burst of rains even during the month of April.

The past few days have been relatively dry over most of Tamil Nadu but the arrival of a lower atmospheric trough associated with a weak Upper Air Cyclonic Circulation over the equatorial waters of Bay has now created the next window of rains for parts of Tamil Nadu. In this context one must also keep in mind the northern parts of the state will more often than not come under drier conditions due to increased influence of Northerly winds compared to say parts of Delta & adjoining areas of South Coastal TN.

With weather models indicating the Equatorial trough to move west over the next couple of days it could bring a bit of wind convergence & moisture incursion over coastal areas of Tamil Nadu between Chidambaram & Ramanathapuram while over the South Tamil Nadu some of the moisture could get pushed onto the Eastern slopes of the Ghats giving rains over places like Srivilliputhur / Watrap etc.

Mostly the rains are expected to be light to moderate for the next 3 / 4 days though occasionally isolated places could see heavier spell of rains due to wind convergence, particularly between Tarangambadi & Manalmelkudi. There is one other small thing which could not be ignored in the overall scheme of things. The presence of MJO over Indian Ocean, even though it is expected to favor Southern Indian Ocean more, a spillover will surely be enough to enhance the rains in a few places.

As of now Chennai may not see any major spell of rains though it remains to be seen if the situation is going to be similar when the next spell of rains happen around middle of next week under similar conditions.