Over the past few days one of the often asked question is about Northeast Monsoon Revival. With monsoon dynamics remaining weak the question started to becoming louder. But what is forgotten is how good monsoon has been so far this year. For the first time since the start of the season we have had 4 consecutive days of below average rains. The lack of rains around Chennai meant doubts about Northeast Monsoon revival became stronger. As a weather blogger it is always essential to set aside personal bias. It is also very essential to give a clear indication on what to expect without this personal bias.
The development of Severe Cyclonic Storm Dana and its northward movement disturbed the Easterlies. The discussions on the authenticity of Monsoon onset is relevant though both sides have a case. While there could be doubt on Monsoon onset there is no doubt on Northeast Monsoon revival. Westerly winds have now pushed well south of Peninsular India. Easterlies are likely to return to Bay soon in the next 24 hours or so. This in turn will create an East West Shear Zone over Equatorial and adjoining South Bay. This East west shear zone is likely to set the stage for Monsoon revival. Potentially two disturbances is likely to develop within this Shear zone.
The first of the disturbance could be a weak one majorly influencing South Tamil Nadu and Delta districts. Likely to be a Trough of Low this will bring widespread rains to South TN and adjoining areas from Friday. Weather models indicate this trough may remain stationary until the arrival of the 2nd pulse later next week. With the first fortnight events influenced majorly by Equatorial Rossby wave we could see both these disturbances remain marginal. The 2nd disturbance is likely to be a Well Marked Low / Depression when it comes closer to North TN / South AP. There is a 50:50 chance this could potentially become a Deep Depression or marginal cyclone. We will have better clarity on this as things evolve.
Northeast Monsoon during the 2nd fortnight of November will see a major fillip given by the arrival of MJO over Indian Ocean. This could mean the peak season for Northeast Monsoon 2024 will potentially be the 2nd fortnight of November and 1st fortnight of December. MJO transit is likely to remain favourable for Peninsular India during the 2nd fortnight of November. 1st fortnight of December may see MJO over EIO and adjoining MTC. This could be mean a regular arrival of circulations into Bay of Bengal from South China Sea.
As things stand there is a very high probability for Northeast Monsoon to see above average rains during November with pockets of Excess along coastal TN. Two periods as listed in the Take away need to be under watch for heavy / very heavy rains leading to water logging or localised flooding events. Individual impact areas will be known closer to the events based on clarity of intensity and track of LPA / Depression. There is no reason for anyone including those from Chennai to worry about a failure monsoon this year.