The arrival of Southwest Monsoon is one of the most eagerly awaited days across the country, to call it as the most significant weather event of the countrty is an understatement. June 1 is the long term average arrival date for Southwest Monsoon to hit the shores of Kerala.
While the IMD has a certain parameters to decide when monsoon has arrived in Kerala, this article pertains to one of the most important factors that decide the birth and progress of Southwest Monsoon in India. The High Pressure Zone straddled over the South Indian Ocean between Australia and Madagascar is the powerhouse that creates the environment for the winds to travel all the way from South Indian Ocean to the Indian Peninsular carrying moisture as Southwest Monsoon.
This process normally kicks off around the 2nd fortnight of April. Here we try a comparison of the conditions that existed between last year and this year to understand are the conditions right for Southwest Monsoon to keep up its date with the Indian Coast. The images are compared exactly with a one year difference so that we can clearly understand what was happening last year and what is happening this year.
In the above image from last year one can clearly see a developing HPA thats pushing the winds in a Northerly direction. While in the below image which is from yesterday the winds are still disorganized with no signs of the HPA forming
Similarly if one has to observe the status of cross equatorial wind pattern same time last year there was a clear indication of developing cross equatorial wind pattern at both surface levels and 850 hPa levels.
But this year the cross equatorial winds are still to show any firm signs of development indicating a possible delay in development of ideal conditions.It all points to a possible delay in the conditions developing for Southwest Monsoon, but will it mean a delay in the onset of Southwest Monsoon over the coast of Kerala we need to wait and watch as in the past things have changed fast during the course of the season. Is the devleoping El Nino a reason for the delay in condtions is again debatable but could be a firm indicator of how El Nino could possibly affect our season.