In a press briefing Madhavan Rajeevan, the secretary at the Ministry of Earth Sciences (MoES) stated, “We will have a normal monsoon this year. Quantitatively the monsoon rainfall during the monsoon season 2020 is expected to be 100% of its long period average with an error of +5 or -5% due to model error".
The India Meteorological Department (IMD) defines average, or normal, rainfall as between 96 percent and 104 percent of a 50-year average of 88 centimeters for the entire four-month season beginning June.
In its first stage Long Range Forecast (LRF) for south-west monsoon season (June-September) rainfall, the weather bureau also gave the dates of onset in several places.
The official said the date for the onset of monsoon in Kerala remains the same and will arrive on June 1. The date for Chennai will be June 4, Panjim June 7, Hyderabad June 8, Pune 10 and Mumbai 11.
The monsoon will arrive in the national capital on June 27.
LRF is the operational monsoon season forecast issued by the weather department from June to September for the entire country. It does not include regional level rainfall or specifies quantum rainfall for the forecast period.
The MeT department issues LRF in two stages—first stage forecast in April and the second one is issued in June.
These forecasts are issued using Statistical Ensemble Forecasting System (SEFS) and dynamical coupled ocean-atmospheric models.
India receives about 70% of its annual rainfall during the monsoon that generally begins in June before starting to retreat by September.
The monsoon rainfall is essential to rice, wheat, sugarcane and oil seeds cultivation in the country, where farming accounts for about 15% of the economy and employs over half of its people.