IMD FORECASTS RAPID SOUTHWEST MONSOON

Why in the news?

  • IMD forecasts rapid southwest monsoon progress to east, central, and western India by the weekend, compensating for delays.
  • Expected complete coverage of Gujarat, Madhya Pradesh, Chhattisgarh, Jharkhand, Bihar, and West Bengal by June 29, with further expansion into Uttar Pradesh, Uttarakhand, Himachal Pradesh, Jammu & Kashmir, Ladakh, Punjab, and Haryana.
Source: Phys

Factors Influencing South-West Monsoon Formation :

  • Differential heating and cooling between land and sea creates low pressure over Indian landmass, contrasting with high pressure over surrounding seas.
  • The Inter Tropical Convergence Zone (ITCZ), shifting northwards to the Ganga plain in summer, serves as a crucial equatorial trough where northeast and southeast trade winds converge.
  • High-pressure area east of Madagascar at approximately 20°S in the Indian Ocean significantly influences the Indian Monsoon.

Intense summer heating of the Tibetan plateau generates strong vertical air currents, forming a high-altitude low-pressure area.

  • Movement of the westerly jet stream north of the Himalayas and the tropical easterly jet stream over the Indian peninsula during summer are pivotal.
  • Southern Oscillation (SO) alternates pressure conditions between the tropical eastern South Pacific and Indian Oceans, affecting monsoon variability.
Divisions of Monsoon in India

India has four seasonal divisions, with the monsoon encompassing two:

  • Southwest Monsoon Season: Occurs from June to September, characterized by seasonal rainfall brought by southwest winds.
  • Retreating Monsoon Season: Takes place in October and November, marked by the withdrawal of southwest monsoon winds from the Indian subcontinent.