Monsoon to be 'Normal' This Year: IMD

India will witness a normal monsoon this year (assessed at 98 percent of long-period average LPA), which is on a row that aligns with two consecutive years of an above-normal monsoon in 2019 and 2020, as per the long-range monsoon forecast by India Meteorological Department (IMD) on Friday. 

The forecast based on the operational Statistical Ensemble Forecasting System advised that quantitatively, the seasonal monsoon rainfall is likely to be 98 percent of the LPA with a model error of ± 5 percent. The LPA of the season rainfall over the country for the period 1961-2010 is 88 cm. 

The five-section probability forecasts for the seasonal (June to September) rainfall over the country based on the SEFS forecast suggests the maximum probability for the seasonal rainfall to be normal (which defines as 96-104 percent of LPA). 

The spatial distribution of probabilistic forecasts for tercile categories (above normal, normal, and below normal) for the seasonal rainfall suggests either normal or above normal probability is likely over most parts of the country, M Rajeevan, Secretary, Ministry of Earth Sciences, said in a virtual press conference on Friday.  

He indicated that the eastern parts of the country might alone witness drier than usual conditions and deficient rain during the impending season. 

La Nina phase easing 

The La Nina phase in the Equatorial Pacific Ocean, among the major climatological factors deciding the monsoon play-out, is easing and is close to the threshold in prevailing sea-surface temperatures (SSTs). 

The La Nina phase tends to support a good monsoon, as was the case in the last year. According to Rajeevan, graph predictions support a transition to the ‘neutral’ phase by May. 

Indian Ocean Dipole 

The Indian Ocean Dipole (IOD), the twin of the Pacific phenomenon near home, is also checked to be in the neutral phase, Rajeevan said, with a tendency to go to the negative mode during the Monsoon. 

The forecast by the national forecaster for a normal monsoon follows by a ‘healthy normal monsoon’ outlook made available on Tuesday by Skymet Weather, a leading private sector forecaster, and assessed at 103 percent of the LPA. 

The forecast of a good monsoon for the third consecutive year should bring good tidings for the farm economy even as the Covid-19 pandemic in most parts of the country.