Sunday, May 24, 2009

Monsoon Watch-13

As discussed in the last blog, the result of the initial gush of the south west winds in the Arabian Sea towards the deep depression in the bay , has resulted in the monsoon setting in over Kerala on the 23rd. of May. 8 days before the due date !

BUT, let 's see what todays streamline map indicates: It shows a strong south west monsoon current, just south of the tip of India. Over the state of Kerala, today, it is not as strong as it was yesterday. The "pull" of the winds towards the newly formed cyclone is effective south of the Indian coast. In fact, international weather forecasts predict a reduction in the intensity of rain over Kerala from the 25th. for the next 3/4 days. After that, say from the 28th, regrouping of the monsoon current may take effect, and the monsoon can subsequently progress along the west coast northwards. And, today (24th.), the reduced effect is already seen, with Kochi recieving 8mm of rain and Thiruvananthpuram 3mm. only !
It could well be a "false start", in Jim's words.

Meanwhile, the deep depression in the bay, has intensified in to a named cyclone, "Aila".
It is expected to intensify further, and cross the W.B./Bangladesh coast by the 25th. night.
It should pull up the monsoon upto the northern fringes of the bay within the next 2 days.

As mentioned, I repeat again, after crossing the coast, the cyclone will weaken, and then allow the Arabian Sea south-westerlies to re-group.

Re-grouping (after the 28th.), may not take long, as the necassary parameters are already in place. The pressure gradient is enough today, the heat in the Sindh/Rajasthan region is sufficient, and spreading westwards, and the seasonal low is firm with a core of 994/996mb.

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