“The forecast based on both dynamical and statistical models suggests that quantitatively, the monsoon seasonal rainfall is likely to be 96% of the long period average (LPA) with a model error of ± 5%,” said M Ravichandran, secretary, ministry of earth sciences, while releasing the monsoon forecast of India Meteorological Department (IMD).
The forecast falls in the lowest end of the normal range of 96 to 104% of the LPA. IMD said the country is likely to receive 83.5cm of rainfall during the season (June-September) as against a normal of 87cm, based on data of 1971-2020. The climatological (normal) probability of “normal to above normal” rainfall in any year is around 67%.
The 2023 monsoon season is likely to be normal, as per the forecast, despite evolving El Nino conditions (unusual warming of surface waters in eastern Pacific Ocean) that is generally linked to weak monsoon rains. IMD director general M Mohapatra, however, said that not all El Nino years resulted in poor rains and that in 40% of such years there was normal to above-normal rainfall.
IMD released data to show that out of 15 El Nino years during 1951-2022, six received normal to above normal rainfall. The met department, however, said the possible development of El Nino conditions around July may impact monsoon during the second half (August-September) of season.
Asked whether any private forecaster is allowed to issue monsoon forecasts as it sometimes creates confusion, Mohapatra said the IMD is the globally recognised nodal weather agency of India and is part of the World Meteorological Organisation (WMO) as one of the 193 member countries and, therefore, people should believe in the forecast of official forecaster.
“Please believe in the IMD whose forecast is not only judicious, reasonable and timely but has also accountability. If anyone (private agency) makes a forecast with no accountability then there will be a problem (in terms of reliability),” he said, without taking names.
Releasing details of the forecast for 2023 monsoon, Mohapatra emphasised that as per weather models, the southwest (summer) monsoon seasonal (June to September) rainfall over the country is likely to be normal with the highest probability among all other categories of 35%, against the climatological probability of 33%.
Though even the “below normal” situation did not pose any serious challenge to the country’s foodgrain output in the past decade, the IMD’s prediction of “normal” rainfall will, in any case, be a big relief for farmers specifically in those regions where the irrigation network is not as robust as it is in the north-west India including Punjab, Haryana, Rajasthan and western Uttar Pradesh. Only “deficient” rainfall poses problems in almost all parts of the country.
In terms of geographical distribution, “normal to below-normal” rainfall is predicted over parts of northwest India, west-central, parts of Gujarat and Maharashtra and northeast regions during the summer monsoon season whereas “normal” rainfall is likely over many parts of the peninsular region, adjoining the east-central, east, northeast areas and some parts of northwest India.
Watch Monsoon season expected to be normal in 2023: IMD
