• India Meteorological Department (IMD) has predicted that country as a whole is likely to receive 96% of Long Period Average (LPA) for southwest monsoon from June to September 2023.
  • LPA of rainfall is the precipitation recorded over a particular region for a given interval (like a month or season) average over a long period like 30 years or 50 years.
  • In last four years (2019 to 2022), India has received normal to above normal rainfall.
  • IMD’s forecast considers following three factors that affects Indian monsoon
    1. El Nino: it is associated with diminished rainfall in India.
    2. Indian Ocean Dipole (IOD): IOD refers to the difference in sea-surface temperatures in Eastern and Western parts of Indian Ocean.
      • Positive IOD is considered good for Indian monsoon.
    3. Snow Cover: Winter and spring snow cover extent over Northern Hemisphere and Eurasia has a general inverse relationship with subsequent summer monsoon rainfall.


Category of Rainfall

  • Deficient < 90% of LPA
  • Below Normal 90 – 95% of LPA
  • Normal 96 -104 % of LPA
  • Above Normal 105 -110% of LPA
  • Excess > 110% of LPA


About El Nino Southern Oscillation

  • El Nino is warm phase of El Nino-Southern Oscillation (ENSO), where unusual warming of surface waters in eastern tropical Pacific Ocean occurs.
  • La Nina is cool phase of ENSO, and since 2019, India has been under influence of the La Nina, getting substantial monsoon rains.


About India Meteorological Department (IMD)

  • It is an agency of the Ministry of Earth Sciences.
  • It is the principal agency responsible for meteorological observations, weather forecasting and seismology.
  • It is also one of the six Regional Specialised Meteorological Centres of the World Meteorological Organisation.
  • IMD releases the long range forecast in two stages in April and June.
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