Environment

Monsoon advances, but in deficit

Reasons for delay: Weak El Nino conditions, very severe Cyclone Vayu

 
By Akshit Sangomla
Last Updated: Friday 21 June 2019
Photo: GettyImages

After a long delay and slow pace of progress, the south west monsoon’s (SWM) advance hastened a bit, the India Meteorological Department (IMD) said on June 20. The rains have already reached parts of Maharashtra, Goa and West Bengal while covering greater areas of Kerala, Tamil Nadu and Karnataka, the weather agency said.

IMD forecast that the SWM will further move into Andhra Pradesh, Telangana, Sikkim, Bihar, Jharkhand and Odisha by the first half of the week starting June 20 and into Gujarat, Madhya Pradesh and Uttar Pradesh by the second half.

Monsoon showers will come as some respite to a country reeling under the double whammy of deficit rainfall and heat waves for the past two months.

Currently, the monsoon deficit for the country as a whole is 43 per cent. Central India is the worst hit and has received 54 per cent below normal rainfall. The south Peninsular region, a large part of which has already received the monsoon rains, has a deficit of 38 per cent. If the monsoon rains are intense enough then the scare of this month being the driest June month on record will get abated but the current situation is far from that.

The intensity of the monsoon rains in the states in which they have arrived does not lift hopes. The state of Kerala which received its first rains on June 8 still has a rainfall deficit of 38 per cent till June 20. Tamil Nadu and Karnataka also do not fare any better with deficits of 35 and 33 per cent respectively. Within Karnataka, the coastal region has a highest deficit of 44 per cent.

There are a couple of reasons for the delay in the onset and the weak start of the SWM season. First, the presence of weak El Nino conditions in the equatorial Pacific Ocean which is the unusual warming of the sea surface which can cause the disruption of trade winds that act as carriers of the monsoon winds.

Second, the development, propagation and dissipation of the very severe cyclone Vayu in the Arabian Sea between June 9 and 18. The cyclone also blocked the progress of the trade winds and weakened them, taking away the strength of the monsoon rains.

The initial monsoon rains are important for the farmers in various regions of the country as they need to sow their crop. A large deficit of rainfall in June and erratic rainfall later will mean increased chances of drought in the months ahead.

Many regions in India like Maharashtra are already suffering from drought from the deficient rainfall last year. 

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