Context

IMD in a press briefing has forecast that the rains in June-September will be 6% more than these months, an annual average of 87 cm.

India to Get Above Normal Rain this Monsoon Season 2024

• The forecasts also indicate that “above-normal” rain was likely over most parts of the country except northwest, east and northeast India.
• The models indicate a 30% chance of monsoon rains being over 10%, categorized as ‘excess’.
  • Usually the chances of excess rain  in any given year  is only a 17%

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• Factors: 
  • Emerging La Nina: The  El Nino  is expected to fade away by June and progress to La Nina (a converse cooling effect in the Central Pacific  region that is  usually linked to surplus rainfall by the second half of the monsoon  ie. August and September).
    • El Nino last year dented India’s monsoon by 6%. 
  • A positive Indian Ocean Dipole (A cooler than normal Indian Ocean in the east as compared to the west) though currently ‘neutral’, it is expected to turn positive by August.
  • It will help bring rain to several States in southern India. 
    • Below normal snow cover in the Northern Hemisphere and Eurasia: The snow cover level in Eurasia and Indian monsoon shares an inverse relationship
• Approach used by IMD to forecast monsoon: 
  • Statistical Approach: To  draw upon IMDs vast historical database of over 150 years to correlate certain global meteorological parameters such as ocean temperatures and snow cover in Europe etc. to the performance of the monsoon. 
  • Dynamic Approach: It is to simulate the weather across the globe on a particular day, and to extrapolate this weather into any future day or time period desired.