Easterly wave to give more than just rains to coastal areas

Weather Update

In cricket matches when things don’t go as per plans and the batting team has the number of the all the main bowlers many a time teams have opted to bring in a part-time bowler who is not exactly known for his / her wicket taking prowess. While often this is made in a hope of taking a wicket by luck the progressive thinking teams use this option not just to see if a lucky wicket falls but also to realign the rhythm of the well set batsman particularly in test matches when new ball is available shortly. A slight distraction in concentration by the batsman gives a chink in the armor for the regular new ball bowlers to aim at with renewed vigor. While part timers were mostly used to break the monotony people like Sachin Tendulkar were a genuine wicket taking option and not just break the monotony.

In a way easterly waves could be compared to the bowler in Sachin Tendulkar or may be even “the singer in Kamalhassan” could be a better analogy. Someone who could have possibly carved a career out of singing too even if he did not continue to act. Weather bloggers in their earnest efforts to look out for Cyclones / Depressions many a time ignore the role played by weaker disturbances like easterly waves & troughs. We have seen in the past trough of low working its magic in bringing widespread rains and similarly during the later stages of northeast monsoon often easterly waves have brought heavy rains along the coastal areas of Tamil Nadu, particularly to South TN and delta areas.

The next few days coastal TN is likely to come under the influence of an easterly wave that is expected to bring fairly widespread rains from Friday onwards to parts of South TN and delta districts. Chennai and rest of north coastal TN may not receive as much rains as delta and south coastal TN with the easterly wave expected to influence the lower latitudes of peninsular India and Sri Lanka. Consequent to the strengthening easterlies the lower level convergence seen for the past couple of days along the Ghats is expected to fade away gradually reducing the thunderstorms over these areas. Today we might see light to moderate rains along the coast in Delta and South TN with the rainfall intensity expected to pick up from later tomorrow night or early Friday morning. Weekend promises fairly widespread rains for delta districts and south TN which to some extent may cover up deficits few places in these areas are still under.

Now coming back to the part time bowler phenomenon one may wonder why a detailed note on a cricketing event in a weather blog. The upcoming easterly wave is not just going to give rains to delta and south TN but also play another crucial role which is likely to differentiate the upcoming disturbance in Bay of Bengal during the 2nd week of December compared to the unforgettable 94B one of those rare stalled depressions off the coast to give less than 10 mm to many parts of Chennai. As by now most know 94B had an uphill battle against a well entrenched Dry Air over peninsular India and closer to the coast preventing it not only intensifying but also giving very little rains to coastal areas. Dry air sat like two well set batsmen in the crease for more than a week. The upcoming easterly wave is expected to play that underrated part time bowler trick on dry air which has been now sitting over peninsular India for the past few days. This spell of easterlies will push moisture onto peninsular India making things far better closer to the coast than during 94B time though models does indicate a brief return of dry northerlies early next week. So in a way even if the easterly wave does not give enough rains it will play a crucial role of making conditions more favorable for the upcoming disturbance in Bay.

How much this disturbance intensifies and where would it go is subject of a different post in a couple of days time when weather models show more consistency. By that time the pulse would have crossed Indo China peninsular providing a better idea as well on the potential genesis zone.