Southwest monsoon deficit widens to 43% as El Nino, MJO and neutral Indian Ocean Dipole stall rains

India's southwest monsoon has weakened sharply, with the nationwide rainfall shortfall rising from 35% to about 43%. The monsoon winds, which normally move steadily up the west coast, have stalled near Mumbai. Both the India Meteorological Department (IMD) and the United States' NOAA expect a moderate-to-strong El Nino this year. El Nino is a warming of the central Pacific Ocean that suppresses the rising air currents needed to form rain clouds and weakens the trade winds that carry moisture towards the Indian subcontinent.

Three large-scale climate factors are working against India together. The El Nino is suppressing cloud formation, the Madden-Julian Oscillation (MJO), an eastward-moving band of clouds and rainfall, is in an unfavourable phase, and the Indian Ocean Dipole (IOD), which can sometimes boost monsoon rain, is currently neutral and offers no cushion. The shortfall is also very uneven across regions. Northwest India has received about 5% more rain than normal, but central India faces a 63% deficit and the northeast a 43% deficit.

There is no reason for panic yet. Historically about two-thirds of the season's rain arrives in July and August, so the monsoon can still recover. Reservoir storage stands at 30.4% of capacity, higher than the 25.1% seen during earlier El Nino years, giving some buffer for drinking water and power. The bigger worry is farming: extreme heat is cutting the productivity of farm labour, and a poor start threatens the cardamom crop in Idukki and other plantation crops of the Western Ghats.

For policy, the stress falls on the kharif sowing window for rice, pulses and oilseeds, and on fertilizer availability. The Agriculture Ministry has already flagged 111 of 315 vulnerable districts as priority based on how much irrigation they have, so that a weak monsoon does not turn into a food and price shock. A delayed monsoon can push up food inflation and force greater reliance on irrigation and reservoirs.

Aspirants should remember the three drivers of the Indian monsoon, El Nino (and its cool opposite La Nina), the Madden-Julian Oscillation and the Indian Ocean Dipole, and how El Nino years tend to mean below-normal rain. Link this to kharif crops, reservoir storage and the idea of a 'normal' monsoon defined against the long period average.