When will the impact of El Nino reach Indian Ocean region?
The Pacific is developing an exceptionally strong El Nino, and it is reasonable to describe it as a potential ‘Super El Nino.’ A Super El Nino is an exceptionally strong El Nino event in which sea-surface temperatures in the central and eastern equatorial Pacific become much warmer than normal, producing a major reorganization of tropical atmospheric circulation, particularly the Walker circulation.
The Walker Circulation is a large-scale, east–west atmospheric movement of air across the tropical Pacific Ocean driven by sea surface temperature and pressure differences.
The latest observations show that the event is still intensifying rather than weakening. NOAA’s September diagnostic reported Central Pacific benchmark region around +1.8°C for August, while eastern equatorial Pacific region and South American coast were already +2.5°C and +3.4°C, respectively.
The El Nino signal is already influencing the Walker circulation, so its atmospheric impact on the Indian Ocean region has begun. The main question now is when this influence will become strongest over the tropical Indian Ocean, the Arabian Sea, and the Bay of Bengal.
IOD to enter a positive phase and more rains in southern peninsula during summer. Is this correct?
This is partly correct. The latest IMD outlook indicates normal rainfall overall across south peninsular India, with normal-to-above-normal rainfall expected in some southern areas including Tamil Nadu.
As Pacific warming approaches its forecast peak, altered trade winds and convection may increasingly affect equatorial Indian Ocean winds, cloud cover and air–sea heat exchange. The timing and magnitude of the response will depend on Indian Ocean conditions, including the Indian Ocean Dipole (IOD).
The WMO’s latest outlook forecasts a positive IOD peaking around October 2026 and weakening thereafter. This could reinforce or oppose some regional effects of El Nino, depending on location and season.
Centre expects drought and crop loss in North India
Wheat production is likely to face the impact due to warmer winter temperature under the ensuing El Nino. India’s winter wheat crop is generally sown from October to December and harvested from March to April. The crop’s most vulnerable period for heat damage is often February–March, when grain filling takes place. Higher temperatures during February–March 2027 could shorten grain filling and reduce yields, especially if soil moisture is inadequate. For wheat, winter and spring temperature may be as important as rainfall. Even if irrigation water is available, unusually high temperatures during grain filling can reduce yields.
For mustard and pulses, moisture stress during flowering and grain filling may reduce yields. The risk is particularly important in the Indo-Gangetic plains, where wheat and rice production is nationally significant.
Western disturbances (WDs) are one of the most important weather systems controlling winter temperature fluctuations over northern and northwestern India. Western disturbances are eastward-moving weather systems originating mainly in the Mediterranean–West Asian region. They travel towards India, often embedded in the subtropical westerly jet stream, and are particularly influential from December to March.
The WDs can affect wheat production and yield through both temperature and moisture. For the 2026–27 wheat season, the most important issue is whether WDs provide adequate winter precipitation.
Will El Nino affect the 2027 Southwest Monsoon?
The developing El Nino could affect India’s 2027 southwest monsoon, and the risk of below-normal rainfall deserves attention. El Nino creates a genuine risk of a weaker 2027 Southwest Monsoon. However, as of October 10, it is too early to determine whether the 2027 monsoon will be deficient or how severe any deficit might be.
The latest NOAA assessment indicates that strong-to-very-strong El Nino conditions are likely to persist through January–March 2027. The Indian Ministry of Earth Sciences has also emphasized that the eventual monsoon impact depends on the evolution of the IOD, MJO and regional ocean–atmosphere interactions. The possible consequences could include weaker monsoon circulation over parts of India, longer dry spells and uneven distribution of rainfall, increased risk of agricultural drought and reduced reservoir inflows and higher temperatures and evaporation, increasing irrigation demand.
These are potential consequences, not guaranteed consequences. Even during strong El Nino events, India’s monsoon rainfall has varied substantially.
Will it alter the trade winds?
Yes. El Nino directly alters the tropical trade winds, and those changes are central to how it can affect India’s 2027 southwest monsoon.
Normally, easterly trade winds blow from east to west across the equatorial Pacific, pushing warm surface water towards Indonesia and the western Pacific. During El Nino, these winds weaken, sometimes dramatically, allowing warm water to spread eastward and altering tropical atmospheric circulation.