Every year monsoon is a different experience for weather watchers. Looking into the past to find answers for the future is a time and tested method for long term weather inferences. This is the reason why elsewhere in the Globe weather community does a lot of work to find the right analogs from past years. This year’s SWM is surely another year of learning and experience for weather watchers. One thing though we can say with some assurance. SWM this year has been patchy and performed in bursts for Peninsular India.
On the one hand Mettur reached FRL for the 5th time this year this week. While on the other Kerala’s seasonal SWM performance stands at -12%. For the month of August the rainfall status for Kerala stands at an alarming -27%. This despite a fairly good spell last over the last few days bringing in some much needed rains. This spell of rains was preceded by a dry period that nearly stretched for a fortnight. In short this explains Monsoon performance over Peninsular India this year. For every active spell the period of dry weather is almost 1.5 to 2 times longer.
With MISO now favouring Central India and adjoining Bay of Bengal monsoon has slowed down once again over Peninsular India. This is likely to continue for the next couple of weeks as things stand. Sub seasonal weather outlooks indicate this could possibly stretch until middle of September though it may be prudent to wait and see. Forecasts indicate MJO currently seen over Maritime continent may push further East into Western Hemisphere in a week to 10 days time. This could potentially bring sub par monsoon dynamics over most of the Indian Sub continent.
This could mean the plains of Tamil Nadu, particularly South TN, may see abnormally hot afternoons. Weather models also indicate some thunderstorm activity may happen over the plains of TN with westerlies slowing down. This could extend for the next 3 / 4 days bringing some moderate rains to placs in North TN. When the overall suppressed phase kicks in coinciding with MJO moving into Western Hemisphere a spell of dry and hot weather may persist over the region.
Over the next couple of days North TN may see some evening thunderstorms due to weak mid level wind instabilities. Depending on steering there is some chance for Chennai and suburbs to see some rains. But before that we may have to bear a fairly hot day.