Agri Business

Weather: Easterly flows may revive this week, bring back rains

Vinson Kurian Thiruvananthapuram | Updated on November 09, 2020 Published on November 09, 2020

The Bay of Bengal has remained largely ‘barren’

The North-East monsoon has not been able to rev up to its true potential, hampered even after 10 days after it made a delayed onset over the South Peninsula, mainly on account of lack of adequate number of supporting systems in the form of low-pressure areas or depressions.

The only system of interest concurrently being tracked over the neighbourhood oceans is a cyclonic circulation over Equatorial Indian Ocean and adjoining South Andaman Sea. But it is too far away to the extreme South-East Bay of Bengal to be of any immediate significance.

 

In fact, global model forecasts ― as does short-to-medium-term outlook by the India Meteorological Department (IMD) ― indicate that the circulation may generate some traction but in the wrong direction ― towards Equatorial Indian Ocean and to the South of Sri Lanka.

Also read: La Nina contributes to marked upswing in world agri prices

Eastern flows to resume

But the system would be capable of influencing an entire regime of easterly to its north over the Bay of Bengal and favourably impact the North-East monsoon flows towards the East Coast of India, including the Tamil Nadu and Andhra Pradesh coasts later into this week.

The IMD has forecast that the rainfall may gradually pick up after next two days along the coast of Tamil Nadu and spread thin over the rest of South Peninsular India. Coastal Tamil Nadu, including Chennai, may receive better organised rain from Saturday, Diwali day.

Global model forecasts are more or less in agreement suggesting normal to above-normal rainfall during this period, before plateauing to normal again during November 18 to 27. Rainfall may improve from the end of November due to favourable patterns in the upstream South China Sea.

Also read: Return on National Monsoon Mission was 50-fold: NCAER study

N-E monsoon in deficit till date

Meanwhile, the rainfall from October 1 to November 10 (monsoon transition period and into North-East monsoon) has been 4 per cent below normal for the country as a whole (categorised by IMD in the normal) after the North-East monsoon itself fell into the deficit category over the South Peninsula.

The rainfall deficits range from 62 per cent in Lakshadweep, 48 per cent in Puducherry, 44 per cent in Tamil Nadu, and 32 per cent in Kerala over the South Peninsula. Andhra Pradesh logged in a deficit of 6 per cent (normal) while Telangana recorded a rainfall surplus of 62 per cent.

Also, in surplus is Karnataka (23 per cent), as per IMD statistics. But these surpluses are mostly drawn from the non-seasonal heavy to very heavy rainfall recorded over these regions during the monsoon transition period in October, which, in fact, was responsible for the delayed arrival of the North-East monsoon.

The Chennai weather bloggers see the emerging situation over the next few days as depicted below:

https://twitter.com/ChennaiRains/status/1325589431353442306?s=20

https://twitter.com/ChennaiRains/status/1325398604064808961?s=20

https://twitter.com/chennaisweather/status/1325005739958493185?s=20

https://twitter.com/chennaiweather/status/1325629673003384832?s=20

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Published on November 09, 2020
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