Quantitatively, the southwest monsoon seasonal (June to September) rainfall over the country as a whole is likely to be 96% of the Long Period Average (LPA) with a model error of ± 5% (Normal) this year, the India Meteorological Department (IMD) said in a report.
“The forecast based on both dynamical and statistical models suggests that quantitatively, the monsoon seasonal rainfall is likely to be normal this year,” reads the IMD report.
The IMD also stated that LPA of the season rainfall over the country as a whole for the period 1971-2020 previously was 87 cm.
La Nino conditions are likely to develop during the monsoon season, its impact may only be felt during the second half of the season, IMD said.
The agency of the Ministry of Earth Sciences has shared the five category probability forecasts for the Seasonal (June to September) rainfall over the country as a whole, which suggests the higher probability for monsoon seasonal rainfall to be normal.
The IMD has also mentioned that April initial conditions have been used for generating the Multi-Model Ensemble (MME) forecast for 2023 southwest Monsoon season rainfall.
The spatial distribution of probabilistic forecasts for tercile categories (above normal, normal and below normal) for the seasonal rainfall (June to September) is shown in Figure below. The spatial distribution suggests normal to above normal rainfall likely over many areas of Peninsular India and adjoining East Central India, Northeast India and over some parts of Northwest India. Normal to below normal rainfall is likely over some areas of Northwest India and parts of Westcentral India and some pockets of Northeast India. White shaded areas within the land represent climatological probabilities.
The figure illustrates the most likely categories as well as their probabilities. The white-shaded areas represent climatological probabilities for all the tercile categories. The probabilities were derived using the MME forecast prepared from a group of best-coupled climate models.(*Tercile categories have equal climatological probabilities, of 33.33% each).