NEW DELHI: The Indian Meteorological Department (IMD) has predicted that the monsoon is likely to begin over parts of the south Bay of Bengal, the Andaman Sea, and the Andaman and Nicobar Islands towards the end of this week (May 16-17).
“Conditions are turning favourable for the onset of the southwest monsoon over parts of the south Bay of Bengal, Andaman Sea, and Andaman and Nicobar Islands by the end of this week,” stated the IMD in its daily weather forecast.
The traditional schedule for the arrival of the Southwest Monsoon in the Nicobar Islands is May 15, with coverage of the entire Andaman Sea typically by May 20.
This year, the expected arrival of the SWM aligns with this timeline.
“It appears that the onset of the monsoon over the South Andaman Sea is nearly on schedule,” said Dr Mrutyunjay Mohapatra, Director General of Meteorology at the IMD, in an interview with TNIE.
Last year, the SWM reached the South Andaman Sea, parts of the southeast Bay of Bengal, and the Nicobar Islands by May 13, arriving earlier than the normal schedule.
Climatologically, the SWM covers the Andaman Sea by May 20 and reaches the coast of Kerala by June 1.
Earlier predictions by the IMD indicated a below-normal SWM season for 2026 (June to September), which poses challenges for Indian agriculture amid an energy crisis.
The forecast suggests that monsoon rainfall may reach only 92 per cent of the long-period average (LPA), with a model error margin of ±5%, marking one of the lowest predictions in recent years.
The LPA for seasonal rainfall across the country is based on data from 1971 to 2020, which amounts to 870 mm. This year, anticipated rainfall is expected to be around 800 mm.
The low rainfall forecast is primarily attributed to the emergence of strong El Niño conditions. The El Niño-Southern Oscillation (ENSO) is a natural climate phenomenon characterised by abnormal warming in the Central and Eastern Pacific Ocean.
El Niño is often associated with a weaker and more erratic monsoon in India.
According to the IMD, since 1951, there have been 16 recorded El Niño years, of which only six contradicted the expectations of a weaker monsoon.
Out of the 10 years that recorded deficient or below-normal rainfall, the patterns were consistent with El Niño effects. Additionally, reduced snow cover in the Northern Hemisphere over the last three months has also contributed to expectations of a weaker monsoon.
Last year, India experienced above-normal monsoon rainfall, with the season concluding at 108 per cent of expected levels.
Furthermore, the private weather agency Skymet has also predicted below-normal rainfall at 94 per cent of the LPA.
